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We're making an open-source $30 GPS/mesh radio, would like advice

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Re: We're making an open-source $30 GPS/mesh radio, would like advice

#131

Post by foobarian »

rapjr9 wrote: post #85
keithwinstein wrote: post #65

Earlier quoted context omitted.

That's true in practice with current radios, but it was a beautiful discovery in 2006 that it's not true in theory! In a world where radios are perfect and nodes cooperate to do decentralized beamforming, the capacity-per-node of a random mesh network scales as the number of nodes increases. See Ozgur, Leveque, and Tse, "Hierarchical Cooperation Achieves Optimal Capacity Scaling in Ad Hoc Networks," IEEE Trans. Info.…

Interesting. I wonder how well it would work in practice though. They assume uniform randomly distributed nodes, whereas people don't tend to distribute themselves randomly. They don't address practical concerns either, like how narrow the MIMO beamwidths need to be and how easy that is to achieve. Still a nice theoretical result.

This seems like it requires point-to-point communication; and with accurate MIMO configuration my intuition for the endpoints is that it's like they are communicating with laser-like narrow beams but in RF. But AFAIK multihop communication is still stuck at sqrt(n) scaling, i.e. not viable.

This is all pretty theoretical though, for a small number of nodes like up to 100 it should work pretty well like in the OP application.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#132

Post by myself248 »

bloopernova wrote: post #130
punkgeek wrote: post #2

Hi ya'll, so we've spent a few weeks making device software and an android app to convert a $30 chinese gps/radio into a long range mesh radio for hikers. It is working fairly well now (though still an alpha) and we'd love more people to try it and/or have fun coding on it. We got about 30 users (and some devs from this hackaday article) but we'd love more users and devs to join this happy-happy project: https://hack…

Is there anything I, as a sysadmin-by-experience, can do to help out? I don't have any relevant skills for radio or SDR stuff, but I'd love to mess around with it for a couple of hours a week.

I'm not involved with the project, but I think you can probably get this running. The hardware is cheap, the install instructions are pretty straightforward, and if you know which end of a USB cable is which, you'll be able to bumble through.

Keep notes as you do, and that can feed directly into improving the documentation to be more noob-friendly.

You'll find more ways to get involved from there, including just using and sharing the project with friends.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#133

Post by myself248 »

superkuh wrote: post #11
jkoberg wrote: post #8

Earlier quoted context omitted.

What frequency band are you using? ISM is the only one that permits store-and-forward / automatic operation, as the gotenna people found. You say a few miles per node - I am having trouble seeing how that's possible without elevating all the nodes

He's gotta be assuming the nodes have clear line of sight and fresnel zone. The maximum distance for the link budget in a perfect situation. In practice it probably cuts off at the nearest rise in the ground or depression. But they're still cool and I still want some for non-hiking applications. With the very low power idle and low cost they could be set up with solar panels in the tops of trees or in similar high he…

I used to get about a mile on 900MHz Ricochet radios, one of which was sitting on a chair in the living room, the other of which was sitting on the passenger seat of my car. Around a mile, the usable data rate would fall below 4800bps, and my NMEA packets would stop going through.

I find it entirely believable that a lower data-rate modulation could get better range than that, even on less power and worse antennas.

And you can do a LOT with antennas on 900MHz.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#134

Post by bloopernova »

myself248 wrote: post #132
bloopernova wrote: post #130

Earlier quoted context omitted.

Is there anything I, as a sysadmin-by-experience, can do to help out? I don't have any relevant skills for radio or SDR stuff, but I'd love to mess around with it for a couple of hours a week.

I'm not involved with the project, but I think you can probably get this running. The hardware is cheap, the install instructions are pretty straightforward, and if you know which end of a USB cable is which, you'll be able to bumble through. Keep notes as you do, and that can feed directly into improving the documentation to be more noob-friendly. You'll find more ways to get involved from there, including just usin…

I'm adding myself to the Gitter channel and will hook up a radio to my home office Raspberry Pi. I'm excited to be a part of this! :)

Thanks for the encouragement, by the way. I really appreciate that.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#135

Post by myself248 »

punkgeek wrote: post #24
atourgates wrote: post #23

Really cool. Seems like an open-source mashup of something like Lynq https://lynqme.com/ - and Gotenna https://gotennamesh.com/ I've never liked Gotenna's requirement to be paired with a cellphone for tracking, so I've been watching Lynq's development for a while. But, I'd much rather have an open-source solution than one that depends on the fortunes and whims of a single compnay. Particularly if there was easy-to-us…

yes, that's what we thought also. Also, the phone is optional for our case (though you need it for sending texts - if you don't have one the display still shows rxed texts and headings/distance to members of the channel)

In my case, only the Heltec boards were easily available, and they lack the GPS that's in the TTgo boards. So I hope there's a way for the phone's GPS to participate!

(Or, since the esp32 has bluetooth, recognize a bluetooth GPS puck? That's extra work and they're quite rare, so maybe nah.)

Otherwise I'm totally fine soldering another GPS onto some random GPIO pins, I have a whole bag of those. I'm just not sure what it would take to get it recognized.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#137

Post by luma »

ruslan wrote: post #121

I'm just curious why my comment regarding patent was deleted ? Yes we developed a device that implements this same idea of sharing GPS data over mesh (868 ISM) network and patented it in 2014. The patent is still valid and supported. If someone is interested in further development of this idea, please contact me, we would be happy to sell this patent along with schematics and source codes for fair price.

Your post said nothing about the patent itself, and simply stated that this open source project should be paying you. It's not exactly the best approach on a site like this.

How about outlining the specific patent claims you feel are being violated here, along with links to the patents in question? That approach would feel a lot more helpful and a lot less like a shakedown.

If you've somehow managed to get a patent on sending GPS coords over LoRa I think a lot of people in this space are going to be interested in that. Nearly every LoRa application in the field is going to find themselves in violation.

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#138

Post by deedubaya »

Very cool.

There is a general fear in the backcountry Skiing community that any RF devices might impede or negatively impact the use of search and recovery beacons to locate buried partners in the event of an avalanche. Any documentation/speculation on any potential interference?

Re: We're making an open-source $30 GPS/mesh radio, would like advice

#139

Post by [deleted] »

kawfey wrote: post #122
punkgeek wrote: post #2

Hi ya'll, so we've spent a few weeks making device software and an android app to convert a $30 chinese gps/radio into a long range mesh radio for hikers. It is working fairly well now (though still an alpha) and we'd love more people to try it and/or have fun coding on it. We got about 30 users (and some devs from this hackaday article) but we'd love more users and devs to join this happy-happy project: https://hack…

Radio amateurs might be some suitable beta testers for you. It being an open source radio system fits right into the mission and spirit of amateur radio. However, I'll take the cynical route and say mesh radios, for the general public, are still not very popular. Gotenna and Beartooth, among others appear to be common and popular, and highly reviewed, but in my hikes and ski trips, I haven't seen or heard from a sing…

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