Since we found an issue with the AC in our LieberLieber server/network room, we decided to build a temperature watchdog to get an alarm if the AC should fail.

Parts used:

  1. Arduino UNO
  2. DHT22/AM2302 temperature & humidity sensor
  3. SIM900 GPRS/GSM Board Quad-Band Module


We also have some dog owners in the office and I was told this could be the perfect gadget, if you had to leave the dog inside the car.

For this second application, I used a small enclosure with the temperature sensor cut out, a 2000uF Capacitor (since the SIM900 has some current peaks I needed to buffer) and a Powerbank to with two outputs (on with 2.1A output for the SIM900).



If you would like to rebuild it here is the Arduino source code and the readme file: Project Oro