Meshtastic

Snowmobiles, which units / configuration to get?

Hi!
I randomly stumbled upon this fantastic project researching something entirely different. However, I’ve been in the market for a GPS-unit to use with my snowmobile, when going on trips(note:rural/wilderness, far from cell-site coverage). Correct and accurate(within 10 meters) positions are important in this case. When looking into units like the Garmin GPSmap 276CX it has an operating temperature of minimum -15c. Which is not good enough, experiences from other owners of the GPSmap also report this to be an issue. I see the T-beam is rated down to -40c, has anyone tested it in really cold weather?

Position sharing is a nice feature. If I want to do that with the other drivers, we all have to share same devices and/or pay for a subscription fee, when ex. using devices from Garmin.

The two points above have made me look into the Meshtastic.

The thing is I’m not really sure about which units to try out. The Echo looks nice because of all its GNSS options, but I see alot of people are reporting bugs and possible HW issues. And I need to build a weatherproof case with a fixture that withstands the all the prolonged vibrations. Power is generally not an issue, as there is a 12v car cigarette outlet on the snowmobile. For safety however, I think a battery is a nice thing to have.

Any tips/pointers for my use case?

Same here, looking for a system to find people on the mountain. I have seen the gps walkitakies but was not impressed. I ride in the cascades mostly and we don’t get too cold here. For the cold only issue I see is battery might not work as good. Batteries in the radios are lithium, and I carry a starter pack that is also lithium and have not had issues yet. For positional accuracy, I have used the same gps sensor that is on some of the lilygo units and it seems to be as good or better than a phone gps, how its implemented I cant say, as I am just starting to look at these units. I am thinking about getting a couple of T beam modules for testing this season.

T-Echo is confirmed to have a great range within “Line-of-sight”:

E-paper screen update can get very slow at low temperatures.

T-Impulse wristband looks very promising as well. However, it is rather new product and may need some time for the hardware functions to settle down:
LILYGO® TTGO T-Watch GPS + Lora (S76G) watch expansion card - #21 by Linar

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first, it’s important to understand the limitations of a DIY project so you don’t get frustrated comparing it to a $700 commercial product. you will need to invest your own time to experiment, learn and figure out what works best for you. hopefully having fun in the process.

there are not many hardware options with GPS, you can choose between the T-Beam with NEO M8N or a NRF52 based board like the T-Echo or RAK4631.

RAK4631 has far superior quality (and cost), but software is not as mature and reliable as the T-Beams right now.

building a waterproof insulated case for the device may be your biggest challenge. start simple, slap it in a box, add insulation, USB cable through a cable gland going to 12V cig lighter. depending on the range you may get away leaving the antenna inside the case. make sure your GPS antenna is facing the sky.

test.

don’t forget even if the T-Beams work in -40C, you need a smartphone to interface with it.