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This would be a valuable addition to other methods of determining presence in building automation systems. What would it take/cost to build a tiny dedicated dev

by roel_v 11y ago

This would be a valuable addition to other methods of determining presence in building automation systems. What would it take/cost to build a tiny dedicated device that would wake up every, say, 5 seconds, analyze wifi signals (what's called the 'fingerprint' in this system if I understand correctly) and ping the server with that data? More concretely, would it be possible to build such a device for low prices (<50USD) with > say, a month, of battery life?

jakobegger 11y ago
It would probably be best to use a microcontroller instead of a full cpu. I really like the Particle Photon. It costs $20 and is a joy to work with. It barely needs any power in sleep mode, and you can set it to wake up at scheduled intervals. Depending on the battery you use, a month of battery life shouldn't be an issue if it sleeps most of the time. There are other microcontrollers with Wifi and similar capabilities that are even cheaper, like the ESP8266 at around $5, but I haven't worked with those before. EDIT: I just saw you want it to wake up every five seconds --- in that case sleep won't help much and you'll need a big battery for a month of use, since wakeup and scanning for networks takes a few seconds. Waking up less often (eg. every 15min) would be more feasible, but it really depends on your intended use.
- qrv3w 11y ago
  Home automation has always been my main goal. I've been working with some electronic devices as you mentioned. For those interested, Sparkfun has "The Thing": https://www.sparkfun.com/products/13231 https://www.sparkfun.com/products/13231 which is a good way to get into the ESP8266. I've also tried using Raspberry Pis, which works pretty well but are still too big with the battery to go carry around a building. I'm hoping to try the Pi Zero in the future with a small LiPo battery.
  - jakobegger 11y ago
    This looks neat; the integrated Lipo charger is a welcome add-on.

by roel_v 11y ago

jakobegger 11y ago

It would probably be best to use a microcontroller instead of a full cpu. I really like the Particle Photon. It costs $20 and is a joy to work with. It barely needs any power in sleep mode, and you can set it to wake up at scheduled intervals. Depending on the battery you use, a month of battery life shouldn't be an issue if it sleeps most of the time. There are other microcontrollers with Wifi and similar capabilities that are even cheaper, like the ESP8266 at around $5, but I haven't worked with those before. EDIT: I just saw you want it to wake up every five seconds --- in that case sleep won't help much and you'll need a big battery for a month of use, since wakeup and scanning for networks takes a few seconds. Waking up less often (eg. every 15min) would be more feasible, but it really depends on your intended use.

qrv3w 11y ago
Home automation has always been my main goal. I've been working with some electronic devices as you mentioned. For those interested, Sparkfun has "The Thing": https://www.sparkfun.com/products/13231 https://www.sparkfun.com/products/13231 which is a good way to get into the ESP8266. I've also tried using Raspberry Pis, which works pretty well but are still too big with the battery to go carry around a building. I'm hoping to try the Pi Zero in the future with a small LiPo battery.
- jakobegger 11y ago
  This looks neat; the integrated Lipo charger is a welcome add-on.