WiFi Temperature Monitor - Part I

Particle.io has some relatively inexpensive and lightweight IoT boards that connect via WiFi (Photon) or Cellular Networks (Electron). They are focused on providing a fully functioning cloud based IDE for development and production devices. Programming is accomplished via Wiring, the same framework as Arduino. Since the framework is open source down to the bare metal, you can also use C/C++ or ARM assembly.

For my first project with the Photon, I created a wireless temperature monitor that displays in a Google Sheet. I used a TMP36 Sensor and imported the results utilizing Script Editor and this Import JSON Script. The JSON output from the Photon looks like this (“deviceID” intentionally obscured):

{
 "cmd": “VarReturn”,
 "name": “analogvalue”,
 "result": 964,
 "coreInfo": {
   "last_app": “”,
   "last_heard": “2016-05-22T22:00:00.209Z”,
   "connected": true,
   "last_handshake_at": “2016-05-22T21:20:20.002Z”,
   "deviceID": “UNIQUE_ID”,
   "product_id": 6
 }
}

Then the temperature can be calculated based on the voltage output from the TMP36 using Temp °C = 100*(reading in V) - 50.

After importing I also converted to Fahrenheit using T(°F) = T(°C) × 1.8 + 32. Here’s the final output in the Google Sheet using

ImportJSON(https://api.particle.io/v1/devices/UNIQUE_ID/analogvalue?access_token=UNIQUE_TOKEN)