A small circuit that requires some soldering work to be done, will give you a simple tiny pre-programmed thermostat that acts like a relay. Simply configure the temperature you want the relay to create a close circuit and watch the system do its’ magic.
Flip the board on the backside, you should see GND near the terminal blocks. GND is where ground should be inserted and the other pin is Vcc. Plug in the battery 5v into the bottom X1 connector.
In X2 the voltage will be outputted only if the red LED turns on. Turn on the device by pressing S1.
Turn off the device by long pressing S1, after seeing - - - on the screen press s1 again to confirm.
Press S1 when the unit is on to change into configuration mode and use either s2 for up and s3 as down to set the temperature in Celsius when the LED should be active.
Operating Voltage: 2.5-6V
PCB Dimension: 51 x 56 mm (L x W)
Hole Diameter : 3mm
Module chip using ATMEL AT89C2051-24PU & DALLAS 18B20