Jump to content

RONJA: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous edit
Content deleted Content added
VisualWikitext
KolbertBot (talk | contribs)
Bots
1,166,042 edits
m →Top: c/e, add lk
 
(44 intermediate revisions by 31 users not shown)
Line 1: Line 1:
{{about|Reasonable Optical Near Joint Access|other topics|ronja (disambiguation)}}
{{Multiple issues|

{{primary sources|date=May 2017}}
{{advert|date=May 2017}}
{{advert|date=May 2017}}
}}


[[File:Ronja beam Prostejov.jpg|thumb|right|Single high-brightness LED with a cheap [[loupe]] lens creates a bright narrow<ref name="rts_di"/> beam that can stream DVD-quality video over neighbourhoods. A few steps aside and the narrow beam becomes invisible.]]
[[File:Ronja beam Prostejov.jpg|thumb|right|Single high-brightness LED with a cheap [[loupe]] lens creates a bright narrow<ref name="rts_di"/> beam that can stream DVD-quality video over neighbourhoods. A few steps aside and the narrow beam becomes invisible.]]
[[File:Twibright Ronja with its user.jpg|thumb|Twibright Ronja with 130 mm (5 in) diameter lenses, operating on a 1205 m (0.75 mi) link using visible red light, max. range 1300 m (0.81 mi), with HPWT-BD00-E4000 transmit LED. Installed on a rooftop, with its user, in Czech Republic.<ref name="ronja.twibright.com">{{cite web|url=http://ronja.twibright.com/installations.php|title=154 Registered Installations of Ronja|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://images.twibright.com/tns/1208.html|title=[1208] ronja/installations/czech/zdar_n_sazavou|author=|date=|website=images.twibright.com|accessdate=3 June 2017}}</ref>]]
[[File:Twibright Ronja with its user.jpg|thumb|Twibright Ronja with {{convert|130|mm|in|adj=on}} diameter lenses, operating on a {{convert|1205|m|yd|adj=on}} link using visible red light, max. range {{convert|1300|m|yd}}, with HPWT-BD00-E4000 transmit LED. Installed on a rooftop, with its user, in Czech Republic.<ref name="ronja.twibright.com">{{cite web|url=http://ronja.twibright.com/installations.php|title=154 Registered Installations of Ronja|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://images.twibright.com/tns/1208.html|title=[1208] ronja/installations/czech/zdar_n_sazavou|website=images.twibright.com|access-date=3 June 2017}}</ref>]]
[[File:RonjaHolder.jpg|thumb|right|Three bolts preloaded with pink rubber blocks facilitate fine adjustment of the optical head direction with a gear ratio 1:300.<ref name="rts_di"/> The bolt on the right side is a part of a rough adjustment mechanism which allows pointing the optical head in virtually any direction.]]
[[File:RonjaHolder.jpg|thumb|right|Three bolts preloaded with pink rubber blocks facilitate fine adjustment of the optical head direction with a gear ratio 1:300.<ref name="rts_di"/> The bolt on the right side is a part of a rough adjustment mechanism which allows pointing the optical head in virtually any direction.]]
[[File:RonjaFog.jpg|thumb|right|Artificially enhanced picture of a situation where a Ronja link stops working because of heavy fog]]
[[File:RonjaFog.jpg|thumb|right|Artificially enhanced picture of a situation where a Ronja link stops working because of heavy fog]]


'''RONJA''' ('''Reasonable Optical Near Joint Access''') is a [[free-space optical communication]] system originating in the [[Czech Republic]], developed by Karel Kulhavý of Twibright Labs and released in 2001. It transmits data [[wireless]]ly using beams of [[light]]. Ronja can be used to create a 10 Mbit/s [[full duplex]] [[Ethernet]] point-to-point link. It has been estimated that 1000 to 2000 links have been built worldwide <ref>{{Cite journal | doi = 10.1177/0162243910368398| title = Free Space Optics in the Czech Wireless Community: Shedding Some Light on the Role of Normativity for User-Initiated Innovations| journal = Science, Technology & Human Values| volume = 36| issue = 4| pages = 423| year = 2010| last1 = Soderberg | first1 = J.}}</ref>
'''RONJA''' ('''Reasonable Optical Near Joint Access''') is a [[free-space optical communication]] system developed in the [[Czech Republic]] by Karel Kulhavý of Twibright Labs. Released in 2001. It transmits data [[wireless]]ly using beams of [[light]]. Ronja can be used to create a 10&nbsp;Mbit/s [[full duplex]] [[Ethernet]] [[point-to-point (telecommunications)|point-to-point]] [[telecommunications link|link]]. It has been estimated that 1,000 to 2,000 links have been built worldwide.<ref>{{Cite journal | doi = 10.1177/0162243910368398| title = Free Space Optics in the Czech Wireless Community: Shedding Some Light on the Role of Normativity for User-Initiated Innovations| journal = Science, Technology, & Human Values| volume = 36| issue = 4| pages = 423–450| year = 2010| last1 = Soderberg | first1 = J.| s2cid = 145786449}}</ref>


The range of the basic configuration is {{convert|1.4|km|mi|abbr=on}}. The device consists of a receiver and [[transmitter]] pipe (optical head) mounted on a sturdy adjustable holder. Two [[coaxial cable]]s are used to connect the rooftop installation with a protocol translator installed in the house near a [[computer]] or [[network switch|switch]]. The range can be extended to {{convert|1.9|km|mi|abbr=on}} by doubling or tripling the transmitter pipe.
The basic configuration has a range of {{convert|1.4|km|mi|abbr=on}}. The device consists of a receiver and [[transmitter]] pipe (optical head) mounted on a sturdy adjustable holder. Two [[coaxial cable]]s are used to connect the rooftop installation with a protocol translator installed in the house near a [[computer]] or [[network switch|switch]]. By doubling or tripling the transmitter pipe, the range can be extended to 1.9 km (1.2 mi).


Building instructions, blueprints, and schematics are published under the [[GNU Free Documentation Licence]]. Only [[free software]] tools are used in the development. The author calls this level of freedom "User Controlled Technology".<ref name="Ronja - BRL-CAD">{{cite web|url=http://brlcad.org/wiki/Ronja|title=Ronja - BRL-CAD|author=|date=|website=brlcad.org|accessdate=3 June 2017}}</ref> Ronja is a project of [[Twibright Labs]].
Building instructions, blueprints, and schematics are published under the [[GNU Free Documentation Licence|GNU Free Documentation License]], with development using only [[free software]] tools. The author calls this level of freedom "User Controlled Technology".<ref name="Ronja - BRL-CAD">{{cite web|url=http://brlcad.org/wiki/Ronja|title=Ronja – BRL-CAD|website=brlcad.org|access-date=3 June 2017}}</ref> Ronja is a project of [[Twibright Labs]].


== Manufacture ==
== Manufacture ==


The building instructions are written with an inexperienced builder in mind. Basic operations like [[drilling]], [[soldering]] etc., are explained.<ref>{{cite web|url=http://ronja.twibright.com/fundamentals.php|title=Fundamentals of manufacturing operations|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> Several techniques - drilling templates,<ref>{{cite web|url=http://ronja.twibright.com/drawings/|title=All Ronja Drawings|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> detailed checks after soldering,<ref name="Building Ronja 10M Receiver">{{cite web|url=http://ronja.twibright.com/receiver/building.php|title=Building Ronja 10M Receiver|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/transmitter/building.php|title=Building Ronja 10M Metropolis Transmitter|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/twister2/building.php|title=Building Ronja Twister2 PCB|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/nebulus/building.php|title=Building Ronja Nebulus|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> testing procedures<ref>{{cite web|url=http://ronja.twibright.com/tetrapolis/testing.php|title=Testing Ronja Tetrapolis|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/metropolis/testing.php|title=Testing Ronja 10M Metropolis|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/inferno/testing.php|title=Testing Ronja Inferno|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> - are employed to minimize errors at critical places and help to speed up work. [[Printed circuit board]]s are downloadable ready for manufacture, with instructions for the fabhouse.<ref>{{cite web|url=http://ronja.twibright.com/twister2/pcb.php|title=Twister2 PCB|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/transmitter/pcb.php|title=Ronja: Ordering TX PCB's|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> People with no previous experience with building electronics have reported on the mailing list that the device ran on the first try.
The building instructions are written with an inexperienced builder in mind. Basic operations like [[drilling]], [[soldering]] etc., are explained.<ref>{{cite web|url=http://ronja.twibright.com/fundamentals.php|title=Fundamentals of manufacturing operations|website=ronja.twibright.com|access-date=3 June 2017}}</ref> Several techniques – drilling templates,<ref>{{cite web|url=http://ronja.twibright.com/drawings/|title=All Ronja Drawings|website=ronja.twibright.com|access-date=3 June 2017}}</ref> detailed checks after soldering,<ref name="Building Ronja 10M Receiver">{{cite web|url=http://ronja.twibright.com/receiver/building.php|title=Building Ronja 10M Receiver|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/transmitter/building.php|title=Building Ronja 10M Metropolis Transmitter|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/twister2/building.php|title=Building Ronja Twister2 PCB|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/nebulus/building.php|title=Building Ronja Nebulus|website=ronja.twibright.com|access-date=3 June 2017}}</ref> testing procedures<ref>{{cite web|url=http://ronja.twibright.com/tetrapolis/testing.php|title=Testing Ronja Tetrapolis|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/metropolis/testing.php|title=Testing Ronja 10M Metropolis|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/inferno/testing.php|title=Testing Ronja Inferno|website=ronja.twibright.com|access-date=3 June 2017}}</ref> – are employed to minimize errors at critical places and help to speed up work. [[Printed circuit board]]s are downloadable ready for manufacture, with instructions for the fabhouse.<ref>{{cite web|url=http://ronja.twibright.com/twister2/pcb.php|title=Twister2 PCB|website=ronja.twibright.com|access-date=3 June 2017}}</ref><ref>{{cite web|url=http://ronja.twibright.com/transmitter/pcb.php|title=Ronja: Ordering TX PCB's|website=ronja.twibright.com|access-date=3 June 2017}}</ref> People with no previous experience with building electronics have reported on the mailing list that the device ran on the first try.


154 installations worldwide have been registered into a gallery with technical data and pictures.<ref name="ronja.twibright.com"/>
154 installations worldwide have been registered into a gallery with technical data and pictures.<ref name="ronja.twibright.com"/>


== Range ==
== Range ==
With the brightest variant of [[Lumileds]] HPWT-BD00-F4000 LED and 130&nbsp;mm diameter cheap Chinese magnifying glass lenses, the range is 1.4&nbsp;km.<ref name="Ronja - BRL-CAD"/><ref name="docplayer.cz">{{cite web|url=http://docplayer.cz/9741937-Evropsky-polytechnicky-institut-s-r-o-1-soukroma-vysoka-skola-na-morave-kunovice-pocitacove-site.html|title=Evropský polytechnický institut, s.r.o. 1. soukromá vysoká škola na Moravě Kunovice POČÍTAČOVÉ SÍTĚ - PDF|author=|date=|website=docplayer.cz|accessdate=3 June 2017}}</ref> The less bright, but easier to buy E4000 variant of HPWT-BD00 yields 1.3&nbsp;km.<ref>{{cite web|url=http://ronja.twibright.com/metropolis/dist.php|title=Ronja 10M Metropolis, Tetrapolis, Inferno, Rexlator distance issues|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> The speed is always 10 Mbit/s full duplex regardless of the distance.
With the brightest variant of [[Lumileds]] HPWT-BD00-F4000 LED and 130&nbsp;mm diameter cheap magnifying glass lenses, the range is {{cvt|1.4|km|mi}}.<ref name="Ronja - BRL-CAD"/><ref name="docplayer.cz">{{cite web|url=http://docplayer.cz/9741937-Evropsky-polytechnicky-institut-s-r-o-1-soukroma-vysoka-skola-na-morave-kunovice-pocitacove-site.html|title=Evropský polytechnický institut, s.r.o. 1. soukromá vysoká škola na Moravě Kunovice POČÍTAČOVÉ SÍTĚ – PDF|website=docplayer.cz|access-date=3 June 2017}}</ref> The dimmer but more affordable E4000 variant of HPWT-BD00 yields {{convert|1.3|km|mi}}.<ref>{{cite web|url=http://ronja.twibright.com/metropolis/dist.php|title=Ronja 10M Metropolis, Tetrapolis, Inferno, Rexlator distance issues|website=ronja.twibright.com|access-date=3 June 2017}}</ref> The speed is always 10&nbsp;Mbit/s full duplex regardless of the distance.


== Models ==
== Models ==
Line 30: Line 29:
* ''Ronja Inferno'': Range of {{convert|1.25|km|mi|abbr=on}}, invisible infrared light.
* ''Ronja Inferno'': Range of {{convert|1.25|km|mi|abbr=on}}, invisible infrared light.
* ''Ronja Benchpress'': A measurement device for developers for physical measurement of lens/LED combination gain and calculation of range from that
* ''Ronja Benchpress'': A measurement device for developers for physical measurement of lens/LED combination gain and calculation of range from that
* ''Ronja Lopipe'': The original (discontinued) design using red visible light and a RS232 interface for a max 115 kbit/s PPP/SLIP link.<ref>{{cite web|url=https://linas.org/mirrors/atrey.karlin.mff.cuni.cz/2002.01.03/~clock/twibright/ronja/|title=Twibright Labs : Ronja|author=|date=|website=linas.org|accessdate=3 June 2017}}</ref>
* ''Ronja Lopipe'': The original (discontinued) design using red visible light and a RS232 interface for a max 115&nbsp;kbit/s PPP/SLIP link.<ref>{{cite web|url=https://linas.org/mirrors/atrey.karlin.mff.cuni.cz/2002.01.03/~clock/twibright/ronja/|title=Twibright Labs : Ronja|website=linas.org|access-date=3 June 2017}}</ref>


== Limitations ==
== Limitations ==
By definition, clear [[visibility]] between the transmitter and receiver is essential. If the beam is obscured in any way, the link will stop working. Typically, problems may occur during conditions of [[snow]] or dense [[fog]].<ref>{{cite web|url=http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.963.9463&rep=rep1&type=pdf|title=Download Limit Exceeded|author=|date=|website=citeseerx.ist.psu.edu|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://cimsec.org/naval-application-tech-lifi/27242|title=Naval Applications for LiFi: The Transmitting Tool|author=|date=10 August 2016|website=cimsec.org|accessdate=3 June 2017}}</ref> One device weighs 15.5&nbsp;kg<ref name="rts_di"/> and requires 70 hours of building time.<ref>{{cite web|url=http://ronja.twibright.com/faq/cost.php|title=How much does Ronja cost?|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> It requires an ability to set full duplex manually on the network card or switch to take advantage of full duplex,<ref>{{cite web|url=http://ronja.twibright.com/tetrapolis/modules.php|title=Ronja Tetrapolis: Requirements (Modules, Material, Tools, Software)|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> since it doesn't support [[autonegotiation]].<ref name=rts_di>{{cite web|url=http://ronja.twibright.com/tetrapolis/spec.php|title=Ronja Tetrapolis Specification|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> Must be plugged directly into PC or switch using the integral 1 m Ethernet cable.<ref name=rts_di />
By definition, clear [[visibility]] between the transmitter and receiver is essential. If the beam is obscured in any way, the link will stop working. Typically, problems may occur during conditions of [[snow]] or dense [[fog]].<ref>{{cite journal|title=Download Limit Exceeded|citeseerx = 10.1.1.963.9463}}</ref><ref>{{cite web|url=http://cimsec.org/naval-application-tech-lifi/27242|title=Naval Applications for LiFi: The Transmitting Tool|date=10 August 2016|website=cimsec.org|access-date=3 June 2017}}</ref> One device weighs {{cvt|15.5|kg}}<ref name="rts_di"/> and requires 70 hours of building time.<ref>{{cite web|url=http://ronja.twibright.com/faq/cost.php|title=How much does Ronja cost?|website=ronja.twibright.com|access-date=3 June 2017}}</ref> It requires an ability to set full duplex manually on the network card or switch to take advantage of full duplex,<ref>{{cite web|url=http://ronja.twibright.com/tetrapolis/modules.php|title=Ronja Tetrapolis: Requirements (Modules, Material, Tools, Software)|website=ronja.twibright.com|access-date=3 June 2017}}</ref> since it doesn't support [[autonegotiation]].<ref name=rts_di>{{cite web|url=http://ronja.twibright.com/tetrapolis/spec.php|title=Ronja Tetrapolis Specification|website=ronja.twibright.com|access-date=3 June 2017}}</ref> Must be plugged directly into PC or switch using the integral {{convert|1|metre}} Ethernet cable.<ref name=rts_di />


== Technology ==
== Technology ==
Line 39: Line 38:


A complete RONJA system is made up of 2 [[transceivers]]: 2 optical [[transmitters]] and 2 optical [[Optical receiver|receivers]]. They are assembled individually or as a combination. The complete system layout is shown in the [[block diagram]].
A complete RONJA system is made up of 2 [[transceivers]]: 2 optical [[transmitters]] and 2 optical [[Optical receiver|receivers]]. They are assembled individually or as a combination. The complete system layout is shown in the [[block diagram]].

=== Optical receiver - Preamplifier stage ===
=== Optical receiver – Preamplifier stage ===
[[File:RONJA-installations-world.png|thumb|Map showing the distribution of the 153 registered installations of RONJA as of 1 October 2007. Based on data found at the [http://ronja.twibright.com/installations.php official RONJA website]]]
[[File:RONJA-installations-world.png|thumb|Map showing the distribution of the 153 registered installations of RONJA as of 1 October 2007. Based on data found at the [http://ronja.twibright.com/installations.php official RONJA website]]]


The usual approach in FSO (Free Space Optics) [[preamplifier]]s is to employ a [[transimpedance amplifier]]. A transimpedance amplifier is a very sensitive [[broadband]] high-speed device featuring a [[feedback loop]]. This fact means the layout is plagued with stability problems and special compensation of [[PIN diode]] [[capacitance]] must be performed, therefore this doesn't allow selection of a wide range of cheap PIN photodiodes with varying capacitances.
The usual approach in FSO (Free Space Optics) [[preamplifier]]s is to employ a [[transimpedance amplifier]]. A transimpedance amplifier is a very sensitive [[broadband]] high-speed device featuring a [[feedback loop]]. This fact means the layout is plagued with stability problems and special compensation of [[PIN diode]] [[capacitance]] must be performed, therefore this doesn't allow selection of a wide range of cheap PIN photodiodes with varying capacitances.


Ronja however uses a feedbackless design<ref name="Building Ronja 10M Receiver"/> where the PIN has a high working [[electrical resistance]] (100 [[Ohm|kilohm]]s)<ref name="Building Ronja 10M Receiver"/> which together with the total input capacitance (roughly 8 pF, 5 pF PIN and 3 pF<ref>{{cite web|url=http://www.nxp.com/documents/data_sheet/BF908-R_N.pdf|title=NXP Semiconductors: BF 908 Datasheet, page 2, table row "input capacitance at gate 1"|author=|date=|website=nxp.com|accessdate=3 June 2017}}</ref> input [[MOSFET]] [[cascode]]) makes the device operate with a [[passband]] on a 6&nbsp;dB/oct slope of low pass formed by PIN working resistance and total input capacitance.<ref>[http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text), pag 2 upper left, mention about "unwanted lossy integrator".]</ref><ref name="How does Ronja work">{{cite web|url=http://ronja.twibright.com/technotes/how_rx.php|title=How does Ronja work?|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> The signal is then immediately amplified to remove the danger of contamination by [[signal noise]], and then a compensation of the 6&nbsp;dB/oct slope is done by derivator element on the programming pins<ref>{{cite web|url=http://www.nxp.com/documents/data_sheet/NE592.pdf|title=Philips Semiconductors RF Communications Products: NE592 Product specification, page 1 lines 6-7 of the 1st paragraph and page 8, heading "FILTER NETWORKS".|author=|date=|website=nxp.com|accessdate=3 June 2017}}</ref> of an NE592 video amplifier.<ref>[http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text)]</ref><ref name="How does Ronja work"/> A surprisingly flat characteristic is obtained. If the PIN diode is equipped with 3 kΩ working resistor to operate in flat band mode, the range is reduced to about 30% due to [[thermal noise]] from the 3 kΩ resistor.
Ronja however uses a feedbackless design<ref name="Building Ronja 10M Receiver"/> where the PIN has a high working [[electrical resistance]] (100 [[Ohm|kilohm]]s)<ref name="Building Ronja 10M Receiver"/> which together with the total input capacitance (roughly 8 pF, 5 pF PIN and 3 pF<ref>{{cite web|url=http://www.nxp.com/documents/data_sheet/BF908-R_N.pdf|title=NXP Semiconductors: BF 908 Datasheet, page 2, table row "input capacitance at gate 1"|website=nxp.com|access-date=3 June 2017}}</ref> input [[MOSFET]] [[cascode]]) makes the device operate with a [[passband]] on a 6&nbsp;dB/oct slope of low pass formed by PIN working resistance and total input capacitance.<ref>[https://web.archive.org/web/20170809130013/http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text), pag 2 upper left, mention about "unwanted lossy integrator".]</ref><ref name="How does Ronja work">{{cite web|url=http://ronja.twibright.com/technotes/how_rx.php|title=How does Ronja work?|website=ronja.twibright.com|access-date=3 June 2017}}</ref> The signal is then immediately amplified to remove the danger of contamination by [[signal noise]], and then a compensation of the 6&nbsp;dB/oct slope is done by derivator element on the programming pins<ref>{{cite web|url=http://www.nxp.com/documents/data_sheet/NE592.pdf|title=Philips Semiconductors RF Communications Products: NE592 Product specification, page 1 lines 6–7 of the 1st paragraph and page 8, heading "FILTER NETWORKS".|website=nxp.com|access-date=3 June 2017}}</ref> of an NE592 video amplifier.<ref>[https://web.archive.org/web/20170809130013/http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text)]</ref><ref name="How does Ronja work"/> A surprisingly flat characteristic is obtained. If the PIN diode is equipped with 3 kΩ working resistor to operate in flat band mode, the range is reduced to about 30% due to [[thermal noise]] from the 3 kΩ resistor.


=== Optical transmitter - Nebulus infrared LED driver ===
=== Optical transmitter – Nebulus infrared LED driver ===


The HSDL4220 [[infrared]] [[light-emitting diode|LED]] is originally unsuitable for 10 Mbit/s operation. It has a [[Bandwidth (signal processing)|bandwidth]] of 9&nbsp;MHz,<ref>{{cite web|url=http://www.mouser.com/ds/2/239/LiteOn_HSDL_4220_4230-195195.pdf|title=HSDL-4220 Datasheet|author=|date=|website=mouser.com|accessdate=3 June 2017}}</ref> where 10 Mbit/s [[Manchester encoding|Manchester]]-modulated systems need bandwidth of around 16&nbsp;MHz. Operation in a usual circuit with current drive would lead to substantial signal corruption and range reduction. Therefore, Twibright Labs developed a special driving technique consisting of driving the LED directly with 15-fold 74AC04 gate output in parallel with RF voltage applied current-unlimited directly to the LED through large capacitors.<ref>{{cite web|url=http://ronja.twibright.com/schematics/nebulus_00.pdf|title=Ronja Nebulus (infrared transmitter) schematic|author=|date=|website=twibright.com|accessdate=3 June 2017}}</ref> As the voltage to keep the nominal LED average current (100mA) varies with temperature and component tolerances, an AC-bypassed current sense resistor is put in series with the LED. A feedback loop measures voltage on this resistor and keeps it at a preset level by varying supply voltage of the 74AC04 gates. Therefore, the nominally digital<ref>{{cite web|url=http://ecee.colorado.edu/~mathys/ecen1400/pdf/references/74AC04.pdf|title=Fairchild: 74AC04 Datasheet|author=|date=|website=colorado.edu|accessdate=3 June 2017}}</ref> 74AC04 is operating as a structured power [[CMOS]] switch completely in analog mode.
The HSDL4220 [[infrared]] [[light-emitting diode|LED]] is originally unsuitable for 10&nbsp;Mbit/s operation. It has a [[Bandwidth (signal processing)|bandwidth]] of 9&nbsp;MHz,<ref>{{cite web|url=http://www.mouser.com/ds/2/239/LiteOn_HSDL_4220_4230-195195.pdf|title=HSDL-4220 Datasheet|website=mouser.com|access-date=3 June 2017}}</ref> where 10&nbsp;Mbit/s [[Manchester encoding|Manchester]]-modulated systems need bandwidth of around 16&nbsp;MHz. Operation in a usual circuit with current drive would lead to substantial signal corruption and range reduction. Therefore, Twibright Labs developed a special driving technique consisting of driving the LED directly with 15-fold 74AC04 gate output in parallel with RF voltage applied current-unlimited directly to the LED through large capacitors.<ref>{{cite web|url=http://ronja.twibright.com/schematics/nebulus_00.pdf|title=Ronja Nebulus (infrared transmitter) schematic|website=twibright.com|access-date=3 June 2017}}</ref> As the voltage to keep the nominal LED average current (100mA) varies with temperature and component tolerances, an AC-bypassed current sense resistor is put in series with the LED. A feedback loop measures voltage on this resistor and keeps it at a preset level by varying supply voltage of the 74AC04 gates. Therefore, the nominally digital<ref>{{cite web|url=http://ecee.colorado.edu/~mathys/ecen1400/pdf/references/74AC04.pdf|title=Fairchild: 74AC04 Datasheet|website=colorado.edu|access-date=3 June 2017}}</ref> 74AC04 is operating as a structured power [[CMOS]] switch completely in analog mode.


This way the LED [[semiconductor junction|junction]] is flooded and cleared of [[charge carrier|carriers]] as quickly as possible, basically by [[short circuit]] discharge. This pushes the speed of the LED to maximum, which makes the output optical signal fast enough so that the range/power ratio is the same as with the faster red HPWT-BD00-F4000 LED. The side effects of this brutal driving
This way the LED [[semiconductor junction|junction]] is flooded and cleared of [[charge carrier|carriers]] as quickly as possible, basically by [[short circuit]] discharge. This pushes the speed of the LED to maximum, which makes the output optical signal fast enough so that the range/power ratio is the same as with the faster red HPWT-BD00-F4000 LED. The side effects of this brutal driving
technique are: 1) the LED overshoots at the beginning of longer (5&nbsp;MHz/1&nbsp;MHz) impulses to about 2x brightness. This was measured to have no adverse effect on range. 2) A blocking [[ceramic capacitor]] bank backing up the 74AC04 switching array is crucial for correct operation, because charging and discharging the LED is done by short circuit. Under dimensioning this bank causes the leading and trailing edges of the optical output to grow longer.
technique are: 1) the LED overshoots at the beginning of longer (5&nbsp;MHz/1&nbsp;MHz) impulses to about 2x brightness. This was measured to have no adverse effect on range. 2) A blocking [[ceramic capacitor]] bank backing up the 74AC04 switching array is crucial for correct operation, because charging and discharging the LED is done by short circuit. Under dimensioning this bank causes the leading and trailing edges of the optical output to grow longer.


=== Transceiver - Ronja Twister ===
=== Transceiver – Ronja Twister ===

⚫
Ronja Twister is an electronic interface for free space optical datalink based on counter and shift register chips. It is a part of the Ronja design. It is effectively an optical Ethernet transceiver without the optical drive part.<ref>{{cite web|url=http://ronja.twibright.com/twister/|title=Ronja Twister|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref>

⚫
The original design has been superseded with Twister2 but the logic circuit remained the same.<ref>{{cite web|url=http://ronja.twibright.com/twister2/|title=Ronja Twister2|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref>


⚫
Ronja Twister is an electronic interface for free space optical datalink based on counter and shift register chips. It is a part of the Ronja design. It is effectively an optical Ethernet transceiver without the optical drive part.<ref>{{cite web|url=http://ronja.twibright.com/twister/|title=Ronja Twister|website=ronja.twibright.com|access-date=3 June 2017}}</ref>
== Use in education ==
One doctoral dissertation,<ref>{{cite thesis|url=http://hdl.handle.net/2077/24450|title=Johan Söderberg: Free software to open hardware: Critical theory on the frontiers of hacking|type= Doctoral dissertation|publisher= University of Gothenburg|ISBN =9789197544276|location= Sweden|date= 2011|accessdate=3 June 2017}}</ref> 10 master's and bachelor's theses,
<ref>{{cite web|url=https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/8456/Diplomova_prace_bezkabelovy_opticky_prenos_zadani.pdf?sequence=1&isAllowed=y|title=David Němec: Cableless optical transmission (in Czech), master's diploma thesis, Institute of Telecommunications, Faculty of Electrical Engineering and Communication, Brno, Czech Republic, 2012.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>[http://doi.nrct.go.th/doi2/ListDoi/Download/90263/4a3faeca0c76500f4b975eddd036335a?Resolve_DOI=10.14457/KU.the.2011.385 Santi Phasuk (สันติ ผาสุข): Design and Implementation of a Data Transceiver via Visible Light Beam (in Thai with English abstract), master's thesis, Kasetsart University, Bangkok, Thailand, 2011.]</ref>
<ref>{{cite web|url=http://ieeexplore.ieee.org/xpl/abstractReferences.jsp?tp=&arnumber=6415059&url=http://ieeexplore.ieee.org/iel5/6407297/6415022/06415059.pdf?arnumber=6415059|title=Designing and realization of free-space optical link and its diagnostic|first1=P.|last1=Lafata|first2=B.|last2=Bakala|date=1 December 2012|publisher=|pages=1–5|accessdate=3 June 2017|via=IEEE Xplore}}</ref>
<ref name="dspace.vutbr.cz">{{cite web|url=https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/55682/12512.pdf?sequence=2&isAllowed=y|title=Jan Matyáš: FPGA-Based Ronja Twister (full text), Bachelor's Thesis, Department of Computer Systems, Faculty of Information Technology, Brno University of Technology, Czech Republic, 2011.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://digilib.k.utb.cz/bitstream/handle/10563/17383/chobot_2011_dp.pdf?sequence=1&isAllowed=y|title=Bc. Lukáš Chobot: Wireless data transfer via optical modules (in Czech), Diploma Thesis, Faculty of Applied Computer Science, Tomas Bata University, Zlín, Czech Republic, 2011.|author=|date=|website=utb.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://dspace.vutbr.cz/bitstream/handle/11012/4618/Diplomova_prace_opticky_bezkabelovy_prenos.pdf?sequence=1|title=Bc. Filip Němec: Optical Cableless Transmittion (in Czech), Master's Thesis, Department of Telecommunications, Faculty of Electrical Engineering and Communication, Brno University of Technology, Czech Republic, 2010.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://www.fei.stuba.sk/docs/2007/annual_report/14_KTL07.pdf|title=T. Szabo: Design and realization of wireless optical connection RONJA (mentioned in annual report), master's thesis, Department of Telecommunications, Faculty of Electrical Engineering and Information, Slovak University Of Technology in Bratislava, Slovakia, 2007.|author=|date=|website=stuba.sk|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://digilib.k.utb.cz/bitstream/handle/10563/2010/ad%c3%a1mek_2006_dp.pdf?sequence=1&isAllowed=y|title=Bc. Ľubomír Adámek: Wireless Data Transmission (in Czech), Diploma Thesis, Faculty of Applied Computer Science, Tomas Bata University, Zlín, Czech Republic, 2006.|author=|date=|website=utb.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://digilib.k.utb.cz/bitstream/handle/10563/2174/%C5%A1t%C4%9Bp%C3%A1n_2006_bp.pdf?sequence=1&isAllowed=y|title=Libor Štěpán: Wireless Optical Link for LAN Ethernet (in Czech), Bachelor Thesis, Faculty of Applied Computer Science, Tomas Bata University, Zlín, Czech Republic, 2006.|author=|date=|website=utb.cz|accessdate=3 June 2017}}</ref>
<ref name="repository.lib.ncsu.edu">{{cite web|url=https://repository.lib.ncsu.edu/bitstream/handle/1840.16/570/etd.pdf?sequence=1&isAllowed=y|title=M. A. Chancey: Short Range Underwater Optical Communication Links (full text), Master Thesis, North Carolina State University, USA, 2005.|author=|date=|website=ncsu.edu|accessdate=3 June 2017}}</ref>
three high school graduation exams
<ref>{{cite web|url=http://www.chrudim2000.cz/ronja/download/Dokumentace_petr_sadecky.pdf|title=Petr Sádecký: High School Practical Graduation Exam: An Optical Datalink (in Czech), Electrotechnical Vocational High School SPŠE/VOŠ Karla IV. 13, Pardubice, Czech Republic, 2005.|author=|date=|website=chrudim2000.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://www.chrudim2000.cz/ronja/download/Dokumentace_filip_nemec.pdf|title=Filip Němec: High School Practical Graduation Exam: An Optical Datalink Between Two Computers „RONJA 10Mb/s“ (in Czech), Electrotechnical Vocational High School SPŠE/VOŠ Karla IV. 13, Pardubice, Czech Republic, 2005.|author=|date=|website=chrudim2000.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://www.chrudim2000.cz/ronja/download/Dokumentace_vojtech_cizinsky.pdf|title=Vojtěch Čižinský: Optical datalink transmitting 10 Mb/s (in Czech), High School Graduation Exam Technical Documentation, Electrotechnical Vocational High School SPŠE/VOŠ, Pardubice, Czech Republic, 2004.|author=|date=|website=chrudim2000.cz|accessdate=3 June 2017}}</ref>
and one high school vocational activity
<ref>{{cite web|url=http://soc.nidv.cz/data/2007/10-2.pdf|title=Antonín Slováček, Petr Severa: RONJA – an optical datalink (in Czech, listing, result listing), High School Vocational Activity, Electrotechnical Vocational High School SPŠE Kounicova 16, Brno, Czech Republic, 2007.|author=|date=|website=nidv.cz|accessdate=3 June 2017}}</ref> are based largely or completely on Ronja. Some of them present substantial changes, like underwater<ref name="repository.lib.ncsu.edu"/> or FPGA.<ref>{{cite web|url=http://acmbulletin.fiit.stuba.sk/vol3num4/matyasSPY.pdf|title=Jan Matyáš (Faculty of Information Technology Brno University of Technology, Czech Republic): FPGA-Based RONJA Twister, ACM Student Project of the Year 2011 Competition, Information Sciences and Technologies Bulletin of the ACM Slovakia, Special Section on the ACM Student Project of the Year 2011 Competition, Vol. 3, No. 4, pp. 43-44, 2011.|author=|date=|website=stuba.sk|accessdate=3 June 2017}}</ref><ref name="dspace.vutbr.cz"/> Further four doctoral dissertations,
<ref>{{cite web|url=http://acceda.ulpgc.es/bitstream/10553/19268/4/0729129_00000_0000.pdf|title=Julio Francisco Rufo Torres: Contribution to the study of Services Supported on VLC (Visible Light Communications) Networks (in Spanish), Doctoral Thesis, Doctoral Program Cybernetics and Telecommunication, University of Las Palmas de Gran Canaria, University Institute for Technological Development and Innovation in Communications, 2015.|author=|date=|website=ulpgc.es|accessdate=3 June 2017}}</ref>
<ref>[http://doc.utwente.nl/76945/1/thesis_S_Verhaegh.pdf Stefan Jeu Sjraar Verhaegh: How Community Innovation Works - a Material-Semiotic Analysis of the Wireless Leiden Wi-Fi Network Doctoral Dissertation, University of Twente, Netherlands, 2010.]</ref>
<ref>{{cite web|url=http://kutarr.lib.kochi-tech.ac.jp/dspace/bitstream/10173/348/1/1096401348.pdf|title=Charoen Tangtrongbenchasil, " Ubiquitous Optical Wireless Communication Using Optical Micro-Cell System ", Doctoral dissertation, Kochi University of Technology, Japan, 2008.|author=|date=|website=kochi-tech.ac.jp|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://daduke.org/dl/PHDref.pdf|title=Christian Herzog, "K1-yNayTa1-xNbxO3 Thin Films for Integrated Electro-Optics" , Doctoral Dissertation No. 17275, Swiss Federal Institute of Technology in Zurich, Switzerland, 2007.|author=|date=|website=daduke.org|accessdate=3 June 2017}}</ref>
18 master's and bachelor's theses,
<ref>[http://www.green.unito.it/sites/www.green.unito.it/files/2016-Tesi_StefanoTruzzi.pdf Stefano Truzzi: Visible Light Communication, Master Thesis, University of Turin, Italy, 2016.]</ref>
<ref>{{cite web|url=https://liu.diva-portal.org/smash/get/diva2:932438/FULLTEXT01.pdf|title=Md Arifur Rahman: Routing on Resource Allocation in Free Space Optical Network, Diploma Thesis, Department of Science and Technology, Linköping University, Sweden, 2016.|author=|date=|website=diva-portal.org|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://digitalcommons.du.edu/cgi/viewcontent.cgi?article=1046&context=etd|title=Philip McGillis Bain: "Alternative Models of Connectivity: Reclaiming Networked Spaces", Master Thesis, University of Denver, Colorado, USA, 2015. |author=|date=|website=du.edu|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://web.wpi.edu/Pubs/E-project/Available/E-project-032615-203414/unrestricted/Visible_Light_Communication_MQP_Report_Final_2014-2015.pdf|title=S. Ambady, M. Bredes, C. Nguyen: Visible Light Communication, A Major Qualifying Project Report completed in partial fulfillment of the requirements for the degree of Bachelor of Science, Worcester Polytechnic Institute, Worcester, Massachusetts, USA, 2015. |author=|date=|website=wpi.edu|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://bib.irb.hr/prikazi-rad?rad=781381|title=Visible light communications|first=Marko|last=Čaljkušić|date=24 September 2015|website=irb.hr|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://jultika.oulu.fi/files/nbnfioulu-201502141097.pdf|title=Pekka Kamsula: Design and Implementation of a Bi-directional Visible Light Communication Testbed, Master’s Thesis, Department of Electrical and Information Engineering, University of Oulu, Finland, 2015. |author=|date=|website=oulu.fi|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://scholar.google.com/scholar?hl=en&q=M+Pittoni,+Advanced+Topology+Analysis+in+Three+Wireless+Community+Networks&btnG=&as_sdt=1,5&as_sdtp=|title=M Pittoni, Advanced Topology Analysis in Three Wireless Community Networks - Google Scholar|author=|date=|website=scholar.google.com|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://dspace.vutbr.cz/bitstream/handle/11012/27267/JiriHankaBakalarskaprace.pdf?sequence=2|title=Jiří Haňka: Wireless Optical Link (in Czech), Bachelor's Thesis, Department of Radio Electronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Czech Republic, 2013.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://is.muni.cz/th/374246/fi_b/main.pdf|title=Ondřej Vitvar: Analysis and Modification of a High School Network (in Czech), Bachelor Thesis, Faculty of Computer Science, Masaryk university, Brno, Czech Republic, 2013.|author=|date=|website=muni.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://lib.ugent.be/fulltxt/RUG01/001/886/977/RUG01-001886977_2012_0001_AC.pdf|title=Frederik Scheire, David Schouppe: Design of a NRZ gigabit optical receiver with qualization for PCS fiber, Master Dissertation submitted to obtain the academic degree of Master of Science in Electrical Engineering, Department of Information Technology, Faculty of Engineering and Architecture, Ghent University, Belgium, 2012.|author=|date=|website=ugent.be|accessdate=3 June 2017}}</ref>
<ref>[https://apothesis.lib.teicrete.gr/bitstream/handle/11713/1988/RyssakisIoannis2012.pdf?sequence=1&isAllowed=y Rysakis Ioannis: Implementation of a Free Space Optics transceiver (in Greek), Bachelor Thesis, Department of Electronics, Technological Educational Institute of Crete, Greece, 2012.]</ref>
<ref>{{cite web|url=http://dspace.upce.cz/bitstream/handle/10195/46619/JaneckaR_VyuzitiSvetla_PR_2012.pdf?sequence=2|title=Radek Janečka: Using Light for Communication and Measurement, Bachelor's Thesis, Pardubice University, Faculty of Electrical Engineering and Computer Science, Czech Republic, 2012. |author=|date=|website=upce.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://www.vutbr.cz/www_base/zav_prace_soubor_verejne.php?file_id=38091|title=Bc. Leoš Kaňa: Indoor Optical Wireless Link Design, Master's thesis, Brno University of Technology, Faculty of Electrical Engineering and Communication, Department of Radio Electronics, Brno, Czech Republic, 2011.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://dspace.vutbr.cz/bitstream/handle/11012/10181/Diplomov%C3%A1%20pr%C3%A1ce_Jaroslav%20Hor%C3%A1k2.pdf?sequence=1|title=Bc. Jaroslav Horák: Optical Connection (In Czech language) , Master's Thesis in Department of Telecommunications, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czech Republic, 2009|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://is.muni.cz/th/150871/fi_b/thesis.pdf|title=Filip Roth: Methods of optical Communication for Embedded Systems, Bachelor Thesis, Faculty of Informatics, Masaryk University, Brno, Czech Republic, 2008.|author=|date=|website=muni.cz|accessdate=3 June 2017}}</ref>
<ref name="biorob2.epfl.ch">{{cite web|url=http://biorob2.epfl.ch/pages/studproj/birg70000/Semester%20Project-Midterm.ppt|title=Pedro López Estepa: Underwater Optical Communication, Semester Project, Swiss Federal Institute of Technology in Lausanne, Switzerland, 2008. |author=|date=|website=epfl.ch|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://repository.lib.ncsu.edu/bitstream/handle/1840.16/2713/etd.pdf?sequence=1&isAllowed=y|title=J. A. Simpson: A 1 Mbps underwater communications system using LEDs and photodiodes with signal processing capability, Master's Thesis, Graduate Faculty of North Carolina State University, North Carolina, USA, 2007.|author=|date=|website=ncsu.edu|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=https://dip.felk.cvut.cz/browse/pdfcache/bubenl1_2007bach.pdf|title=Lubomír Buben: A Simple GIS, Bachelor's Thesis, Czech Technical University, Faculty of Electrical Engineering, Prague, Czech Republic, 2007.|author=|date=|website=cvut.cz|accessdate=3 June 2017}}</ref>
and one university semester project<ref name="biorob2.epfl.ch"/> cite Ronja.<ref>{{cite web|url=http://ronja.twibright.com/web.php|title=Publications coauthored and citations citing Ronja|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> [[Czech Technical University]] has built a 120 m educational link between the buildings of two faculties for teaching the students practically about FSO.<ref>{{cite web|url=https://www.root.cz/clanky/modra-twibright-ronja-vyukovy-spoj-na-cvut/|title=Modrá Twibright Ronja: výukový spoj na ČVUT - Root.cz|first=Karel|last=Kulhavý|date=|website=root.cz|accessdate=3 June 2017}}</ref><ref>{{cite web|url=http://access.feld.cvut.cz/view.php?cisloclanku=2010120004|title=Bakala, Lafata, CTU: Improving the Functionality of Free-Space Optical Link (in Czech with English abstract).|author=|date=|website=cvut.cz|accessdate=3 June 2017}}</ref> One Czech private university dedicates over a page of their textbook to Ronja.<ref name="docplayer.cz"/>


⚫
The original design has been superseded with Twister2 but the logic circuit remained the same.<ref>{{cite web|url=http://ronja.twibright.com/twister2/|title=Ronja Twister2|website=ronja.twibright.com|access-date=3 June 2017}}</ref>
An additional 12 journal, conference and university articles are based largely on Ronja.
<ref>{{cite web|url=https://www.kics.or.kr/storage/paper/event/20161119_workshop/publish/5C-3.pdf|title=Sung Yub Yu, Se Bong Jang, Suk Chan Kim: Implementation of Visible Light Communication system for Real Time Video Transmission, Pusan National University, South Korea, 2016.|author=|date=|website=kics.or.kr|accessdate=3 June 2017}}</ref>
<ref>{{cite book|url=https://link.springer.com/chapter/10.1007/978-1-4471-5493-8_10|title=Hacking Europe|first=Johan|last=Söderberg|editor-first1=Gerard|editor-last1=Alberts|editor-first2=Ruth|editor-last2=Oldenziel|date=3 June 2017|publisher=Springer London|pages=219–239|accessdate=3 June 2017|via=link.springer.com|doi=10.1007/978-1-4471-5493-8_10}}</ref>
<ref>{{cite web|url=http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6415059&url=http://ieeexplore.ieee.org/iel5/6407297/6415022/06415059.pdf?arnumber=6415059|title=Designing and realization of free-space optical link and its diagnostic|first1=P.|last1=Lafata|first2=B.|last2=Bakala|date=1 December 2012|publisher=|pages=1–5|accessdate=3 June 2017|via=IEEE Xplore}}</ref>
<ref>{{cite web|url=http://access.feld.cvut.cz/view.php?cisloclanku=2012010001|title=P. Lafata, B. Bakala: Diagnostic and Remote Monitoring of FSO Link (in Czech), Czech Technical University, Faculty of Electrical Engineering, Department of Telecommunication Engineering, Czech Republic, 2011.|author=|date=|website=cvut.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://access.feld.cvut.cz/view.php?cisloclanku=2010120004|title=P. Lafata, B. Bakala: Improving the Functionality of Free-Space Optical Link., Czech Technical University, Faculty of Electrical Engineering, Department of Telecommunication Engineering, Czech Republic, 2010.|author=|date=|website=cvut.cz|accessdate=3 June 2017}}</ref>
<ref>{{cite web|url=http://optolab.utko.feec.vutbr.cz/wp-content/uploads/FIL11.pdf|title= Filip Němec, Miloslav Filka: Optical Wireless Transmission in Laboratory , Department of Telecommunications, Brno University of Technology, Brno, Czech Republic, 2011.|author=|date=|website=vutbr.cz|accessdate=3 June 2017}}</ref>
<ref>[http://eei.fei.tuke.sk/data/EEI_II.pdf P. Mišenčík, J. Turán, Ľ. Ovseník: Experimental FSO system RONJA for 625 nm (Experimentálny systém FSO pre 625nm RONJA, in Czech), page 22, Proceeding of the Faculty of Electrical Engineering and Informatics of the Technical University Košice, Technical University Košice, Slovak Republic, 2011.]</ref>
<ref>{{cite web|url=http://www.johansoderberg.net/sub02/Science%20Technology%20Human%20Values-2011-Soderberg-423-50.pdf|title=Johan Söderberg (University of Gothenburg, Department of Sociology and work science): Free Space Optics in the Czech Wireless Community: Shedding Some Light on the Role of Normativity for User-Initiated Innovations, in Science, Technology & Human Values 36, Sweden, 2011.|author=|issn=0162-2439|date=|website=johansoderberg.net|accessdate=3 June 2017}}</ref>
<ref>[http://www.action-m.com/ok2011/files/ok2011-scientific-section-proceedings.pdf P. Lafata, B. Bakala: Low Cost Free-Space Optical System and Its Application, 23rd Conference and Exhibition on Optical Communications 2011-Scientific Section Proceedings, p. 48–51. Agentura Action M, Czech Republic, 2011.]</ref>
<ref>[http://www.action-m.com/ok2011/files/ok2011-scientific-section-proceedings.pdf J. Vodrážka, J. Hrad: Experiment with Simple Prototype for Visible Light Communication , 23rd Conference and Exhibition on Optical Communications 2011-Scientific Section Proceedings, p. 59–61. Agentura Action M, Czech Republic, 2011.]</ref>
<ref>{{cite web|url=http://acmbulletin.fiit.stuba.sk/vol3num4/matyasSPY.pdf|title=Jan Matyáš (Faculty of Information Technology Brno University of Technology, Czech Republic): FPGA-Based RONJA Twister , ACM Student Project of the Year 2011 Competition, Information Sciences and Technologies Bulletin of the ACM Slovakia, Special Section on the ACM Student Project of the Year 2011 Competition, Vol. 3, No. 4, pp. 43–44, 2011.|author=|date=|website=stuba.sk|accessdate=3 June 2017}}</ref>
<ref>[http://www.johansoderberg.net/sub02/czech-freespaceoptics-WIFI.pdf Johan Söderberg (University of Gothenburg, Department of Sociology and work science): Reconstructivism versus critical theory of technology: Alternative perspectives on activism and entrepreneurship in the Czech wireless community, in ''Social Epistemology'', 24: 4, 239–262, Sweden, 2010.]</ref>


== Open source hardware approach ==
== Open source hardware approach ==


Soderberg, studying Ronja sociologically, writes: "Arguably, the first project that vindicated the methods and licensing schemes of free software development, applied those practices to open hardware development, and pulled off a state-of-the-art technology without any backing from universities or firms, was the Ronja project."<ref>{{cite web|url=https://policyreview.info/articles/analysis/how-open-hardware-drives-digital-fabrication-tools-such-3d-printer|title=How open hardware drives digital fabrication tools such as the 3D printer|author=|date=|website=policyreview.info|accessdate=3 June 2017}}</ref>
Soderberg, studying Ronja sociologically, writes: "Arguably, the first project that vindicated the methods and licensing schemes of free software development, applied those practices to open hardware development, and pulled off a state-of-the-art technology without any backing from universities or firms, was the Ronja project."<ref>{{cite journal|url=https://policyreview.info/articles/analysis/how-open-hardware-drives-digital-fabrication-tools-such-3d-printer|title=How open hardware drives digital fabrication tools such as the 3D printer|journal=Internet Policy Review|date=18 June 2013 |volume=2 |issue=2 |access-date=3 June 2017 |last1=Söderberg |first1=Johan |doi=10.14763/2013.2.138 |hdl=10419/213966 |hdl-access=free }}</ref>


The whole [[toolchain]] is built strictly upon free tools<ref>{{cite web|url=http://ronja.twibright.com/sw.php|title=Software used for Ronja development|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> and the [[source code|source files]] are provided, free, under the [[GNU General Public License|GPL]].<ref>{{cite web|url=http://ronja.twibright.com/schematics/|title=All Schematics|author=|date=|website=ronja.twibright.com|accessdate=3 June 2017}}</ref> This allows anyone to enter the development, start manufacture or invest into the technology without [[barriers to entry|entry costs]]. Such costs normally can include [[software licence]] costs, time investment into resolution of compatibility issues between proprietary applications, or costs of [[intellectual property]] licence negotiations. The decision to conceive the project this way was inspired by observed organizational efficiency of [[Free Software]].
The whole [[toolchain]] is built strictly upon free tools<ref>{{cite web|url=http://ronja.twibright.com/sw.php|title=Software used for Ronja development|website=ronja.twibright.com|access-date=3 June 2017}}</ref> and the [[source code|source files]] are provided, free, under the [[GNU General Public License|GPL]].<ref>{{cite web|url=http://ronja.twibright.com/schematics/|title=All Schematics|website=ronja.twibright.com|access-date=3 June 2017}}</ref> This allows anyone to enter the development, start manufacture or invest into the technology without [[barriers to entry|entry costs]]. Such costs normally can include [[software licence]] costs, time investment into resolution of compatibility issues between proprietary applications, or costs of [[intellectual property]] licence negotiations. The decision to conceive the project this way was inspired by observed organizational efficiency of [[Free Software]].


On Christmas 2001, Ronja became the world's first 10 Mbit/s Free Space Optics device with free sources.<ref>{{cite web|url=https://hardware.slashdot.org/story/01/12/22/1432211/build-your-own-10mbitsec-optical-data-link|title=Build Your Own 10Mbit/sec Optical Data Link - Slashdot|author=|date=|website=hardware.slashdot.org|accessdate=3 June 2017}}</ref>
On Christmas 2001, Ronja became the world's first 10&nbsp;Mbit/s Free Space Optics device with free sources.<ref>{{cite web|url=https://hardware.slashdot.org/story/01/12/22/1432211/build-your-own-10mbitsec-optical-data-link|title=Build Your Own 10Mbit/sec Optical Data Link – Slashdot|website=hardware.slashdot.org|date=22 December 2001 |access-date=3 June 2017}}</ref>


Examples of tools used in development:
Examples of tools used in development:


* gEDA gschem ([[Schematic capture]])<ref>{{citation|url=http://geda.seul.org|title=Schematic capture}}</ref>
* [[gEDA]] gschem ([[Schematic capture]])<ref>{{citation|url=http://geda.seul.org|title=Schematic capture}}</ref>
* [[QCad]]
* [[QCAD]]
* [[BRL-CAD]]
* [[BRL-CAD]]
* The PCB program<ref>{{citation|title=PCB|url=http://pcb.geda-project.org/index.html|publisher=gEDA Project}}</ref>
* The PCB program<ref>{{citation|title=PCB|url=http://pcb.geda-project.org/index.html|publisher=gEDA Project}}</ref>
Line 146: Line 88:
{{refbegin}}
{{refbegin}}
*{{citation|url=http://www.oreillynet.com/etel/blog/2007/02/ronja_at_10_mbps_the_next_stag.html|publisher=[[O'Reilly Media|O'Reilly Emerging Telephony]]|title=Ronja at 10 Mbit/s, the next stage in wireless mesh networking?|date=February 19, 2007|author=Andy Oram}}
*{{citation|url=http://www.oreillynet.com/etel/blog/2007/02/ronja_at_10_mbps_the_next_stag.html|publisher=[[O'Reilly Media|O'Reilly Emerging Telephony]]|title=Ronja at 10 Mbit/s, the next stage in wireless mesh networking?|date=February 19, 2007|author=Andy Oram}}
*{{citation|url=https://books.google.com/books?id=2rGVgt7b1dQC&pg=PA56&lpg=PA56&dq=twibright+ronja&source=bl&ots=uxE39WjQe4&sig=87OVQnj2Jl8ki_oHfD36sqac8Uc&hl=de&sa=X&ei=HIVSVLi4H6GV7AaXlYDADA&ved=0CGYQ6AEwCQ#v=onepage&q=twibright%20ronja&f=false|publisher=[[Edward Elgar Publishing]]|title=Bridging the Global Digital Divide|date=January 1, 2003|author=Jeffrey James}} page 56
*{{citation|url=https://books.google.com/books?id=2rGVgt7b1dQC&q=twibright+ronja&pg=PA56|publisher=[[Edward Elgar Publishing]]|title=Bridging the Global Digital Divide|date=January 1, 2003|author=Jeffrey James|isbn=9781843767169}} page 56
* [http://www.unstrung.com/document.asp?doc_id=18416 Unstrung: Da Doo Ron RONJA]
* [https://web.archive.org/web/20061128002104/http://www.unstrung.com/document.asp?doc_id=18416 Unstrung: Da Doo Ron RONJA]
* [https://archive.org/details/Ronja_WSFII_London Ronja talk at WSFII London 2005] (archive.org)
* [https://archive.org/details/Ronja_WSFII_London Ronja talk at WSFII London 2005] (archive.org)
* [http://www.hackaday.com/2005/06/13/ronja-optical-data-link/ Hack a Day: Ronja]
* [http://www.hackaday.com/2005/06/13/ronja-optical-data-link/ Hack a Day: Ronja]
* [https://web.archive.org/web/20120110171006/http://hansmi.ch/articles/ronja Building a Ronja-lightlink: A User Testimonial] (web.archive.org)
* [https://web.archive.org/web/20120110171006/http://hansmi.ch/articles/ronja Building a Ronja-lightlink: A User Testimonial] (web.archive.org)
* [http://brlcad.org/wiki/Ronja The 3D modeling software BRL-CAD, originally developed by the US Army since 1979, showcases Ronja as a project which uses BRL-CAD]
* [http://brlcad.org/wiki/Ronja The 3D modeling software BRL-CAD, originally developed by the US Army since 1979, showcases Ronja as a project which uses BRL-CAD]
* [http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006), which publishes the Ronja design with minor modifications, publishes the Ronja receiver and transmitter schematics virtually unchanged, and features a photograph of a Ronja Twister built on the official Ronja PCB.]
* [https://web.archive.org/web/20170809130013/http://electric2.ee.psu.ac.th/~ton/FSO_Ronja_TENCON2006_Final2.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006), which publishes the Ronja design with minor modifications, publishes the Ronja receiver and transmitter schematics virtually unchanged, and features a photograph of a Ronja Twister built on the official Ronja PCB.]
* [https://www.researchgate.net/profile/Phanumas_Khumsat/publication/224693686_Optical_Front-Ends_for_Low-Cost_Laser-Based_10-Mbps_Free-Space_Optical_Transceiver/links/53fdac840cf22f21c2f82347/Optical-Front-Ends-for-Low-Cost-Laser-Based-10-Mbps-Free-Space-Optical-Transceiver.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Optical Front-Ends for Low-Cost Laser-Based 10-Mbps Free-Space Optical Transceiver" (full text), Proceeding of IEEE Asia Pacific Conference on Circuits and Systems 2006, 1911-1914 (2006), which publishes the Ronja design with minor modifications, publishes the Ronja receiver and transmitter schematics virtually unchanged, and features a photograph of the official Ronja optical heads and holders.]
* [https://www.researchgate.net/profile/Phanumas_Khumsat/publication/224693686_Optical_Front-Ends_for_Low-Cost_Laser-Based_10-Mbps_Free-Space_Optical_Transceiver/links/53fdac840cf22f21c2f82347/Optical-Front-Ends-for-Low-Cost-Laser-Based-10-Mbps-Free-Space-Optical-Transceiver.pdf Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Optical Front-Ends for Low-Cost Laser-Based 10-Mbps Free-Space Optical Transceiver" (full text), Proceeding of IEEE Asia Pacific Conference on Circuits and Systems 2006, 1911–1914 (2006), which publishes the Ronja design with minor modifications, publishes the Ronja receiver and transmitter schematics virtually unchanged, and features a photograph of the official Ronja optical heads and holders.]
* [http://docplayer.cz/9741937-Evropsky-polytechnicky-institut-s-r-o-1-soukroma-vysoka-skola-na-morave-kunovice-pocitacove-site.html I. Rukovanský, M. Horváth, L. Solárik, P. Cícha: Computer Networks (in Czech), a university lecture textbook, European Polytechnic Institute - a Private University, 2015, pages 66-67]
* [http://docplayer.cz/9741937-Evropsky-polytechnicky-institut-s-r-o-1-soukroma-vysoka-skola-na-morave-kunovice-pocitacove-site.html I. Rukovanský, M. Horváth, L. Solárik, P. Cícha: Computer Networks (in Czech), a university lecture textbook, European Polytechnic Institute – a Private University, 2015, pages 66–67]
* [http://hdl.handle.net/2077/24450 Johan Söderberg: Free software to open hardware: Critical theory on the frontiers of hacking], Doctoral Dissertation, University of Gothenburg, {{ISBN|9789197544276}}, Sweden, 2011.
* [http://hdl.handle.net/2077/24450 Johan Söderberg: Free software to open hardware: Critical theory on the frontiers of hacking], Doctoral Dissertation, University of Gothenburg, {{ISBN|9789197544276}}, Sweden, 2011.
* [https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/8456/Diplomova_prace_bezkabelovy_opticky_prenos_zadani.pdf?sequence=1&isAllowed=y David Němec: Cableless optical transmission (in Czech), Master diploma thesis, Institute of Telecommunications, Faculty of Electrical Engineering and Communication, Brno, Czech Republic, 2012.]
* [https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/8456/Diplomova_prace_bezkabelovy_opticky_prenos_zadani.pdf?sequence=1&isAllowed=y David Němec: Cableless optical transmission (in Czech), Master diploma thesis, Institute of Telecommunications, Faculty of Electrical Engineering and Communication, Brno, Czech Republic, 2012.] {{Webarchive|url=https://web.archive.org/web/20181103180130/https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/8456/Diplomova_prace_bezkabelovy_opticky_prenos_zadani.pdf?sequence=1&isAllowed=y |date=2018-11-03 }}
* [http://doi.nrct.go.th/doi2/ListDoi/Download/90263/4a3faeca0c76500f4b975eddd036335a?Resolve_DOI=10.14457/KU.the.2011.385 Santi Phasuk (สันติ ผาสุข): Design and Implementation of a Data Transceiver via Visible Light Beam (in Thai with English abstract), Master Thesis, Kasetsart University, Bangkok, Thailand, 2011. ]
* [http://doi.nrct.go.th/doi2/ListDoi/Download/90263/4a3faeca0c76500f4b975eddd036335a?Resolve_DOI=10.14457/KU.the.2011.385 Santi Phasuk (สันติ ผาสุข): Design and Implementation of a Data Transceiver via Visible Light Beam (in Thai with English abstract), Master Thesis, Kasetsart University, Bangkok, Thailand, 2011. ]
* [http://ieeexplore.ieee.org/xpl/abstractReferences.jsp?tp=&arnumber=6415059&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F6407297%2F6415022%2F06415059.pdf%3Farnumber%3D6415059 B. Bakala: Realization of Optical Link, Bachelor project, Department of Telecommunication Engineering, Czech Technical University, Prague, Czech Republic, 2011.]
* [http://ieeexplore.ieee.org/xpl/abstractReferences.jsp?tp=&arnumber=6415059&url=http://ieeexplore.ieee.org/iel5/6407297/6415022/06415059.pdf?arnumber=6415059 B. Bakala: Realization of Optical Link, Bachelor project, Department of Telecommunication Engineering, Czech Technical University, Prague, Czech Republic, 2011.]{{dead link|date=September 2024|bot=medic}}{{cbignore|bot=medic}}
* [https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/55682/12512.pdf?sequence=2&isAllowed=y Jan Matyáš: FPGA-Based Ronja Twister (full text), Bachelor's Thesis, Department of Computer Systems, Faculty of Information Technology, Brno University of Technology, Czech Republic, 2011. ]
* [https://dspace.vutbr.cz/xmlui/bitstream/handle/11012/55682/12512.pdf?sequence=2&isAllowed=y Jan Matyáš: FPGA-Based Ronja Twister (full text), Bachelor's Thesis, Department of Computer Systems, Faculty of Information Technology, Brno University of Technology, Czech Republic, 2011. ]{{Dead link|date=April 2024 |bot=InternetArchiveBot |fix-attempted=yes }}
* [http://digilib.k.utb.cz/bitstream/handle/10563/17383/chobot_2011_dp.pdf?sequence=1&isAllowed=y Bc. Lukáš Chobot: Wireless data transfer via optical modules (in Czech), Diploma Thesis, Faculty of Applied Computer Science, Tomas Bata University, Zlín, Czech Republic, 2011. ]
* [http://digilib.k.utb.cz/bitstream/handle/10563/17383/chobot_2011_dp.pdf?sequence=1&isAllowed=y Bc. Lukáš Chobot: Wireless data transfer via optical modules (in Czech), Diploma Thesis, Faculty of Applied Computer Science, Tomas Bata University, Zlín, Czech Republic, 2011. ]
* [https://dspace.vutbr.cz/bitstream/handle/11012/4618/Diplomova_prace_opticky_bezkabelovy_prenos.pdf?sequence=1 Bc. Filip Němec: Optical Cableless Transmittion (in Czech), Master's Thesis, Department of Telecommunications, Faculty of Electrical Engineering and Communication, Brno University of Technology, Czech Republic, 2010. ]
* [https://dspace.vutbr.cz/bitstream/handle/11012/4618/Diplomova_prace_opticky_bezkabelovy_prenos.pdf?sequence=1 Bc. Filip Němec: Optical Cableless Transmittion (in Czech), Master's Thesis, Department of Telecommunications, Faculty of Electrical Engineering and Communication, Brno University of Technology, Czech Republic, 2010. ]
Line 169: Line 111:


== External links ==
== External links ==
{{commons category}}
{{commonscat}}
* {{official|http://ronja.twibright.com}}
* {{official|http://ronja.twibright.com}}
* [http://www.ece.ncsu.edu/seniordesign/projects_new.php?id=463 RONJA Adaptation for Underwater]
* [https://web.archive.org/web/20140416191936/http://www.ece.ncsu.edu/seniordesign/projects_new.php?id=463 RONJA Adaptation for Underwater]
* [http://charon.hkfree.org/ronja/ British council project - Promotion of ronja in community networks in UK 2004]
* [https://web.archive.org/web/20070509055342/http://charon.hkfree.org/ronja/ British council project – Promotion of ronja in community networks in UK 2004]


[[Category:Free software projects]]
[[Category:Free software projects]]

Latest revision as of 20:42, 4 November 2024

This article is about Reasonable Optical Near Joint Access. For other topics, see ronja (disambiguation).
Single high-brightness LED with a cheap loupe lens creates a bright narrow[1] beam that can stream DVD-quality video over neighbourhoods. A few steps aside and the narrow beam becomes invisible.
Twibright Ronja with 130-millimetre (5.1 in) diameter lenses, operating on a 1,205-metre (1,318 yd) link using visible red light, max. range 1,300 metres (1,400 yd), with HPWT-BD00-E4000 transmit LED. Installed on a rooftop, with its user, in Czech Republic.[2][3]
Three bolts preloaded with pink rubber blocks facilitate fine adjustment of the optical head direction with a gear ratio 1:300.[1] The bolt on the right side is a part of a rough adjustment mechanism which allows pointing the optical head in virtually any direction.
Artificially enhanced picture of a situation where a Ronja link stops working because of heavy fog

RONJA (Reasonable Optical Near Joint Access) is a free-space optical communication system developed in the Czech Republic by Karel Kulhavý of Twibright Labs. Released in 2001. It transmits data wirelessly using beams of light. Ronja can be used to create a 10 Mbit/s full duplex Ethernet point-to-point link. It has been estimated that 1,000 to 2,000 links have been built worldwide.[4]

The basic configuration has a range of 1.4 km (0.87 mi). The device consists of a receiver and transmitter pipe (optical head) mounted on a sturdy adjustable holder. Two coaxial cables are used to connect the rooftop installation with a protocol translator installed in the house near a computer or switch. By doubling or tripling the transmitter pipe, the range can be extended to 1.9 km (1.2 mi).

Building instructions, blueprints, and schematics are published under the GNU Free Documentation License, with development using only free software tools. The author calls this level of freedom "User Controlled Technology".[5] Ronja is a project of Twibright Labs.

Manufacture

[edit]

The building instructions are written with an inexperienced builder in mind. Basic operations like drilling, soldering etc., are explained.[6] Several techniques – drilling templates,[7] detailed checks after soldering,[8][9][10][11] testing procedures[12][13][14] – are employed to minimize errors at critical places and help to speed up work. Printed circuit boards are downloadable ready for manufacture, with instructions for the fabhouse.[15][16] People with no previous experience with building electronics have reported on the mailing list that the device ran on the first try.

154 installations worldwide have been registered into a gallery with technical data and pictures.[2]

Range

[edit]

With the brightest variant of Lumileds HPWT-BD00-F4000 LED and 130 mm diameter cheap magnifying glass lenses, the range is 1.4 km (0.87 mi).[5][17] The dimmer but more affordable E4000 variant of HPWT-BD00 yields 1.3 kilometres (0.81 mi).[18] The speed is always 10 Mbit/s full duplex regardless of the distance.

Models

[edit]
  • Ronja Tetrapolis: Range of 1.4 km (0.87 mi), red visible light. Connect with 8P8C connector into a network card or switch.
  • Ronja 10M Metropolis: Range of 1.4 km (0.87 mi), red visible light. Connects to Attachment Unit Interface.
  • Ronja Inferno: Range of 1.25 km (0.78 mi), invisible infrared light.
  • Ronja Benchpress: A measurement device for developers for physical measurement of lens/LED combination gain and calculation of range from that
  • Ronja Lopipe: The original (discontinued) design using red visible light and a RS232 interface for a max 115 kbit/s PPP/SLIP link.[19]

Limitations

[edit]

By definition, clear visibility between the transmitter and receiver is essential. If the beam is obscured in any way, the link will stop working. Typically, problems may occur during conditions of snow or dense fog.[20][21] One device weighs 15.5 kg (34 lb)[1] and requires 70 hours of building time.[22] It requires an ability to set full duplex manually on the network card or switch to take advantage of full duplex,[23] since it doesn't support autonegotiation.[1] Must be plugged directly into PC or switch using the integral 1 metre (3 ft 3 in) Ethernet cable.[1]

Technology

[edit]
Block diagram of a full duplex RONJA system.

A complete RONJA system is made up of 2 transceivers: 2 optical transmitters and 2 optical receivers. They are assembled individually or as a combination. The complete system layout is shown in the block diagram.

Optical receiver – Preamplifier stage

[edit]
Map showing the distribution of the 153 registered installations of RONJA as of 1 October 2007. Based on data found at the official RONJA website

The usual approach in FSO (Free Space Optics) preamplifiers is to employ a transimpedance amplifier. A transimpedance amplifier is a very sensitive broadband high-speed device featuring a feedback loop. This fact means the layout is plagued with stability problems and special compensation of PIN diode capacitance must be performed, therefore this doesn't allow selection of a wide range of cheap PIN photodiodes with varying capacitances.

Ronja however uses a feedbackless design[8] where the PIN has a high working electrical resistance (100 kilohms)[8] which together with the total input capacitance (roughly 8 pF, 5 pF PIN and 3 pF[24] input MOSFET cascode) makes the device operate with a passband on a 6 dB/oct slope of low pass formed by PIN working resistance and total input capacitance.[25][26] The signal is then immediately amplified to remove the danger of contamination by signal noise, and then a compensation of the 6 dB/oct slope is done by derivator element on the programming pins[27] of an NE592 video amplifier.[28][26] A surprisingly flat characteristic is obtained. If the PIN diode is equipped with 3 kΩ working resistor to operate in flat band mode, the range is reduced to about 30% due to thermal noise from the 3 kΩ resistor.

Optical transmitter – Nebulus infrared LED driver

[edit]

The HSDL4220 infrared LED is originally unsuitable for 10 Mbit/s operation. It has a bandwidth of 9 MHz,[29] where 10 Mbit/s Manchester-modulated systems need bandwidth of around 16 MHz. Operation in a usual circuit with current drive would lead to substantial signal corruption and range reduction. Therefore, Twibright Labs developed a special driving technique consisting of driving the LED directly with 15-fold 74AC04 gate output in parallel with RF voltage applied current-unlimited directly to the LED through large capacitors.[30] As the voltage to keep the nominal LED average current (100mA) varies with temperature and component tolerances, an AC-bypassed current sense resistor is put in series with the LED. A feedback loop measures voltage on this resistor and keeps it at a preset level by varying supply voltage of the 74AC04 gates. Therefore, the nominally digital[31] 74AC04 is operating as a structured power CMOS switch completely in analog mode.

This way the LED junction is flooded and cleared of carriers as quickly as possible, basically by short circuit discharge. This pushes the speed of the LED to maximum, which makes the output optical signal fast enough so that the range/power ratio is the same as with the faster red HPWT-BD00-F4000 LED. The side effects of this brutal driving technique are: 1) the LED overshoots at the beginning of longer (5 MHz/1 MHz) impulses to about 2x brightness. This was measured to have no adverse effect on range. 2) A blocking ceramic capacitor bank backing up the 74AC04 switching array is crucial for correct operation, because charging and discharging the LED is done by short circuit. Under dimensioning this bank causes the leading and trailing edges of the optical output to grow longer.

Transceiver – Ronja Twister

[edit]

Ronja Twister is an electronic interface for free space optical datalink based on counter and shift register chips. It is a part of the Ronja design. It is effectively an optical Ethernet transceiver without the optical drive part.[32]

The original design has been superseded with Twister2 but the logic circuit remained the same.[33]

Open source hardware approach

[edit]

Soderberg, studying Ronja sociologically, writes: "Arguably, the first project that vindicated the methods and licensing schemes of free software development, applied those practices to open hardware development, and pulled off a state-of-the-art technology without any backing from universities or firms, was the Ronja project."[34]

The whole toolchain is built strictly upon free tools[35] and the source files are provided, free, under the GPL.[36] This allows anyone to enter the development, start manufacture or invest into the technology without entry costs. Such costs normally can include software licence costs, time investment into resolution of compatibility issues between proprietary applications, or costs of intellectual property licence negotiations. The decision to conceive the project this way was inspired by observed organizational efficiency of Free Software.

On Christmas 2001, Ronja became the world's first 10 Mbit/s Free Space Optics device with free sources.[37]

Examples of tools used in development:

See also

[edit]

Notes

[edit]
  1. ^ a b c d e "Ronja Tetrapolis Specification". ronja.twibright.com. Retrieved 3 June 2017.
  2. ^ a b "154 Registered Installations of Ronja". ronja.twibright.com. Retrieved 3 June 2017.
  3. ^ "[1208] ronja/installations/czech/zdar_n_sazavou". images.twibright.com. Retrieved 3 June 2017.
  4. ^ Soderberg, J. (2010). "Free Space Optics in the Czech Wireless Community: Shedding Some Light on the Role of Normativity for User-Initiated Innovations". Science, Technology, & Human Values. 36 (4): 423–450. doi:10.1177/0162243910368398. S2CID 145786449.
  5. ^ a b "Ronja – BRL-CAD". brlcad.org. Retrieved 3 June 2017.
  6. ^ "Fundamentals of manufacturing operations". ronja.twibright.com. Retrieved 3 June 2017.
  7. ^ "All Ronja Drawings". ronja.twibright.com. Retrieved 3 June 2017.
  8. ^ a b c "Building Ronja 10M Receiver". ronja.twibright.com. Retrieved 3 June 2017.
  9. ^ "Building Ronja 10M Metropolis Transmitter". ronja.twibright.com. Retrieved 3 June 2017.
  10. ^ "Building Ronja Twister2 PCB". ronja.twibright.com. Retrieved 3 June 2017.
  11. ^ "Building Ronja Nebulus". ronja.twibright.com. Retrieved 3 June 2017.
  12. ^ "Testing Ronja Tetrapolis". ronja.twibright.com. Retrieved 3 June 2017.
  13. ^ "Testing Ronja 10M Metropolis". ronja.twibright.com. Retrieved 3 June 2017.
  14. ^ "Testing Ronja Inferno". ronja.twibright.com. Retrieved 3 June 2017.
  15. ^ "Twister2 PCB". ronja.twibright.com. Retrieved 3 June 2017.
  16. ^ "Ronja: Ordering TX PCB's". ronja.twibright.com. Retrieved 3 June 2017.
  17. ^ "Evropský polytechnický institut, s.r.o. 1. soukromá vysoká škola na Moravě Kunovice POČÍTAČOVÉ SÍTĚ – PDF". docplayer.cz. Retrieved 3 June 2017.
  18. ^ "Ronja 10M Metropolis, Tetrapolis, Inferno, Rexlator distance issues". ronja.twibright.com. Retrieved 3 June 2017.
  19. ^ "Twibright Labs : Ronja". linas.org. Retrieved 3 June 2017.
  20. ^ "Download Limit Exceeded". CiteSeerX 10.1.1.963.9463. {{cite journal}}: Cite journal requires |journal= (help)
  21. ^ "Naval Applications for LiFi: The Transmitting Tool". cimsec.org. 10 August 2016. Retrieved 3 June 2017.
  22. ^ "How much does Ronja cost?". ronja.twibright.com. Retrieved 3 June 2017.
  23. ^ "Ronja Tetrapolis: Requirements (Modules, Material, Tools, Software)". ronja.twibright.com. Retrieved 3 June 2017.
  24. ^ "NXP Semiconductors: BF 908 Datasheet, page 2, table row "input capacitance at gate 1"" (PDF). nxp.com. Retrieved 3 June 2017.
  25. ^ Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text), pag 2 upper left, mention about "unwanted lossy integrator".
  26. ^ a b "How does Ronja work?". ronja.twibright.com. Retrieved 3 June 2017.
  27. ^ "Philips Semiconductors RF Communications Products: NE592 Product specification, page 1 lines 6–7 of the 1st paragraph and page 8, heading "FILTER NETWORKS"" (PDF). nxp.com. Retrieved 3 June 2017.
  28. ^ Phanumas Khumsat, Noppadol Wattanapisit, Karel Kulhavey, "Low-Cost Laser-Based Wireless Optical Transceiver for 10-Mbps Ethernet Link", Proceedings of IEEE Region 10 Conference (TENCON), Hong Kong, China (2006) (full text)
  29. ^ "HSDL-4220 Datasheet" (PDF). mouser.com. Retrieved 3 June 2017.
  30. ^ "Ronja Nebulus (infrared transmitter) schematic" (PDF). twibright.com. Retrieved 3 June 2017.
  31. ^ "Fairchild: 74AC04 Datasheet" (PDF). colorado.edu. Retrieved 3 June 2017.
  32. ^ "Ronja Twister". ronja.twibright.com. Retrieved 3 June 2017.
  33. ^ "Ronja Twister2". ronja.twibright.com. Retrieved 3 June 2017.
  34. ^ Söderberg, Johan (18 June 2013). "How open hardware drives digital fabrication tools such as the 3D printer". Internet Policy Review. 2 (2). doi:10.14763/2013.2.138. hdl:10419/213966. Retrieved 3 June 2017.
  35. ^ "Software used for Ronja development". ronja.twibright.com. Retrieved 3 June 2017.
  36. ^ "All Schematics". ronja.twibright.com. Retrieved 3 June 2017.
  37. ^ "Build Your Own 10Mbit/sec Optical Data Link – Slashdot". hardware.slashdot.org. 22 December 2001. Retrieved 3 June 2017.
  38. ^ Schematic capture
  39. ^ PCB, gEDA Project

References

[edit]
[edit]
Wikimedia Commons has media related to RONJA.
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=RONJA&oldid=1255411189"