GitHub - frolswe/esp-battery-logger: Simple project for the esp8266 using the power saving features of the chip to test the possibility of battery powered sensors.
![Window/Door Sensor - battery powered with relay or FET for backup - Project Guidance - Arduino Forum Window/Door Sensor - battery powered with relay or FET for backup - Project Guidance - Arduino Forum](https://aws1.discourse-cdn.com/arduino/optimized/4X/3/c/a/3caccda458c0928b1275d390f764e0a75e4932f2_2_690x359.png)
Window/Door Sensor - battery powered with relay or FET for backup - Project Guidance - Arduino Forum
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