What is it?

This sensor will allow you to monitor the temperature in various environments. It is tiny, low power and transmitting over a well_known protocol (easy to understand on various devices). I personnally use it with Domoticz and a RFLink to send me an alert if the freezer defrosts or the fridge door is opened for too long.

Startup

Once powered with a 14500 Lithium battery, the green LED lights for 3 seconds. A device ID is randomly generated on the first boot and stored in EEPROM (see the documentation to reset it). The voltage of the battery is transmitetd over X10RF protocol, then the temperature is transmitted using the Oregon Protocol. Then it goes to sleep for 5 minutes. The LED will flash shortly every 8 seconds.

Specifications

• Sensor : from -55°C to +125°C, ±0.5°C Accuracy from -10°C to +85°C, more information here
• Power : lithium-ion 14500 (or AA) size, 3.7-4.2V. For example : here. The battery is not included.
• Power consumption : 5µA while sleeping
• Transmitting delay : 5 minutes (can be adjusted, just tell me in the comments)
• Transmission protocol : Oregon Protocol. Here is an example of decoding with a raspberry, and here a device that natively decodes this protocole in addition on Domoticz or Jeedom.
• Transmitting frequency : 433,92 MHz