Ronja optical data link


Ronja (Reasonable Optical Near Joint Access) is a free technology project. It uses LEDs to create a 10Mbps optical communication link at distances of up to 1.4km. The system was developed using open source tools and the designs are fully disclosed. Everything you need is on the site: schematics, 3D models, and diagrams. The original systems used visible light, but the current designs use infrared. The parts for building one of these units should cost around $60. It’ll probably take at least seventy man hours to put one together so you’d have to be pretty dedicated to not using commodity wi-fi equipment to go through with this.


  1. madd_matt says:

    this is pretty cool.

    If i ever have a need to cheaply create a high speed network bridge over 1.4 km, I’ll know where to look.

    I didn’t see any mention on the site, but does anybody know how much electricity this uses? Could it be powered by a small solar panel? I think this might be handy as a relay across 5 km between two buildings.

  2. elg0nz says:

    well, it depends on the model, but for example in the inferno model specification ( it says it has a power comsumption of 450 mA so I guess it could be possible to power it from a solar panel (although it says something about a heating unit which needs to be considered).

  3. g says:

    Now that is an ugly circuit

  4. Otto says:

    This would be more entertaining if it was more of a hack. Building circuts and such is nice, but I want to see them do it with $10 worth of parts and an off the shelf $3 laser pointer. Because duct-tape engineering is always more entertaining. :)

  5. Skits says:

    This project has been added to my ToDo list… hopefully me and some friends will get one built by next week and we can post the results.

  6. matt2 says:

    be awesome to set up in the office to send to my friend in the cubical about 200 feet away

  7. strider_mt2k says:

    and you can keep french fries warm with it when you aren’t communicating!

  8. Priest says:

    so what if it isn’t a duct tape hack? some people actually take more time and make things that last.

  9. LWATCDR says:

    Yes it is a cool hack but when would it be better than an 802.11b/a/g solution? Maybe in an noisy area?

  10. then you have fog to worry about, or a bird, or tree branches, or…

    not quite as forgiving as a pringles can and a wrt…

  11. micah buckley-farlee says:

    #8, 802.11x’s range is limited by FCC regulations. Visible and infrared light, however, generally has no such limits, besides that of the light source. Of course, radio waves are generally much less affected by fog.
    Obviously 802.11 is more feasible in general, hence its widespread acceptance, but there are probably some situations where this would come quite in handy.

  12. oli jenks says:

    What a fantastic project.

    We recently had our companies BT cables (inculding the whole industrial estates) cut to the net / telephone by some dodgy types. This cost us a couple of days to catch up with orders and general business. Money + Annoyed customers and PHBs.

    With this setup we could have a redant connection even if our cable / ISP went down again.

    Question is, can I get some corporate backing ($$$) to impliment this? Paid for hacks – priceless!

  13. goldfish says:

    just think of the awesome things you could do with this. some ideas:
    – link you and a friend’s house together down the street and play lan games
    – make a wireless link over an entire town using only light
    – make a network of these things in a town center and create a mini internet (a photonet)
    – use a lan based VoIP program and make a light-telephone.
    – use it to connect your secret lair in the garden (aka your shed) to your main network without using insecure 802.x

    just a few ideas ;)

  14. miked says:

    A nearby supermarket has a gas station at the end of the parking lot which is about 1000′ away. The gas station was added well after the market. I assume they did not want to hang a wire or rip a hole through the lot for LAN, so they used this stuff.

  15. Jord says:

    Rather than blasting your porn in every direction, this will provide a much more direct link.
    Being a “hack a day” reader you should know that wifi isn’t secure.

  16. modzilla says:

    will strengthening signal be enuf for longdistance transmission using bluetooth??

  17. Rajendra says:

    i and some friends tries to build a awireless network using
    RONJA(Reasonable Optical Near Joint Access) forour college internal exams
    From which source we can get idea about constructional details

  18. mr Isral Udoh says:

    thank u mr Ronja 4 xposing the knowllage of wireless link. how i wish i see u one on one bcose i know u ve a lot to giv

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