Project Summary: It's now Remote Sniffer cum datalogger
This project helps to know what goes on inside your fridge when it's running. This small sniffer device picks up the temperature and humidity from the surroundings inside the fridge and then transmits on an RF link to a nearby receiver unit. The display changes once in 2 seconds.
To reduce power consumption we've used low power zenner diodes for voltage regulation.
Current it draws is about 13mA. On a small 7.4 volt Li-Ion cell it works for couple of days.
Fridge Sniffer with Datalogger:
With slight modification and adding a Micro SDCard ,it's now a remote sniffer cum data logger. On a CSV file it dumps data every two seconds.
09/07/15: Now I've added two pushbuttons on two digital pins by which one can set the time for datalogging. The extra schematic and the extra code is added at the end. After switching on the power supply just press the hour button & the minute button to set the hour and the minute on the remote receiver panel. Once the time is set just let it be and the data logging will continue. To stop recording just press the other push button on Digital pin-4 and the logging will stop. While data logging on the remote pannel the time shown will be changing once in 2 minutes.