I have yet another side project that I think about from time to time. I belong to a cross country ski club and volunteer to maintain the ski trails in the Bighorn mountains in north-central Wyoming. My goal is to count the skiers that use our trails. The counting part is solved and the data transmit part would be solved using an Electron and MQTT if the site was within cell data range which it is not. I wondering about implementing some sort of bucket-brigade wireless data transfer system using LoRa starting at the trail site with a data forwarding link to eventually reach a site on the top of a mountain that is about two miles as-the-crow-flies from the trails. I’d have good solid access to the cellular network from that other peak (it has an old lookout tower on it). I can put the Electron on the mountain top to receive the data from the LoRa bucket brigade. The trailhead is down in a valley without direct line-of-sight to the mountain top.
I’d appreciate it if others with a broader scope of experience could send pointers of how to research the solution to this problem.
I read your thread about the RFM95w radios. That is a good option.
I’ve also considered:
Satellite Radio - Able to send data from anywhere. I may be able to keep the total cost down to $20-$25/month if I keep the amount of data to a very minimum, which is something like 50 bytes/day. $200 parts cost and very high current (2A?) when transmitting. It might be worth it. Particle’s implementation of the Electron using the always-necessary LiPo battery is a good lesson on how to have high current available on a system that may have a low power main supply.
Cellular amplifier or repeater - I wonder if it is possible to rig up a directional (Yagi) antenna on a closer hill top and beam cellular access down to the trailhead. The people who run the oil fields around here almost always have a cellular amplifier in their truck.
The specific site that I’m referring to is Sibley Lake. If you look at the map, you’ll see Back Mountain only 2 miles to the SE of the lake. Black Mountain is on the edge of the Bighorns and has superb cell data coverage. It doesn’t have direct line-of-sight to the lake.
You should have no problem with the LORA modules + dual directional 900mhz antennas pointed at each other to communication 2-5 miles away, the regular antennas don’t focus the signal like the directional antennas do. That would be much less expensive than the Satellite modem option with the monthly fees.
I had an inspiration today on the drive back from Sibley Lake. There’s only a few weeks of opportunity left to get an Electron setup on Black Mountain before winter makes it impossible to get to the site. I already own the parts to put solar power to it with a big LiPo battery and measure temperature, humidity, and barometric pressure over the winter. By the time it thaws out in May I’ll know a lot more about the end device than I do now. I love the fact that I can update the Electron at a remote site! I can work on the LoRa idea in town and have it ready for next summer.
David, I came across this thread while researching LoRaWAN use in Wyoming, where I have an upcoming sensor network project. Were you successful with the skier counting project using Electron? If you are interested, I can send you an outdoor people counter device and a LoRaWAN gateway at no cost. For me, it’s a good way to test systems in harsh climate. The system can also be used to measure snow height and other parameters with low cost sensors, if needed. Let me know
There’s a British company called Lacuna Space(https://lacuna.space/), which launched their first LoRaWAN based satellite in April 2019. They will add more this year.
