I'm attending to a mountaineering course and today I learnt about the avalanche beacons. They are to me crucial pieces of equipment in winter mountaineering. And plays important roles in saving lives, as first 30 minutes is very important to save a person who's stuck under snow.
I'm considering building several beacons myself using Arduino at low cost and distribute them to my fellow climbers. The thing is I'm not sure where to start. Each beacon should be able two work in two modes. Transmitter and Receiver. And the modes could be changed by a physical switch on the device.
What kind of programming approach do you suggest? Also which wireless transmission module should I use? What is the ideal frequency?
How do the beacons on market today measure the direction and proximity? My guess is they calculate the time in between the pulses. So the receiver side should expect a pulse every second and it should measure any difference -/+ over a second and interpret it as distance? In that case, it should be able to measure the time in VERY VERY granular steps because the signal moves at speed of light. Can Arduino do the measurement? Please correct me if my assumptions are wrong.
Although this is an interesting project that is worth doing for the sake of fun and learning, I don't think it's a good idea to use DIY critical safety equipment when high quality commercial equipment is available. I could maybe see it if you were able to make something that was superior to the commercial equipment but simply saving money is not a good enough reason.
I'm glad you're learning about avalanche safety. My family are avid backcountry skiers and I learned about avalanche beacons, probes, and shovels when I was a kid. Even with all the proper equipment and many decades of experience, we still lost my aunt to an avalanche.
The problem is that normal radio waves do not travel through water. (Snow is only solid water.) If that was possible then avalanche beacons would be as small and cheap as garage door openers.
I believe commercial beacons use a magnetic induction principle. No, they do not use ping-response to measure distance.
Second, you need 24 hours or more in transmit mode because it must be on and transmitting all day when you carry it. Maybe a lot more if you are planning to be out of reach of a charger for several days. That may be a big or expensive battery.
Third, it would be nice but not essential that your beacon is compatible with the common system so that the experienced guy in your party who already has an off-the-shelf one can find you.
pert:
Although this is an interesting project that is worth doing for the sake of fun and learning, I don't think it's a good idea to use DIY critical safety equipment when high quality commercial equipment is available. I could maybe see it if you were able to make something that was superior to the commercial equipment but simply saving money is not a good enough reason.
+++++++++ Absolutly, as a qualified Mountain leader (UK) with a fair bit of past winter mountaineering experience, I would not dream of dishing out DIY 'safety critical equipment' that would just be plain irresponsible.
By all means experiment, not in a real avalanche of course, but if you get a workable design, hand it over to a professional designer (with a big insurance indemnity) to be built.
Each beacon should be able two work in two modes. Transmitter and Receiver. And the modes could be changed by a physical switch on the device.