Add power switching functionality
A box can not powered off without opening the box and removing the battery clip. We need a way to turn it on and off from outside the box.
Possible solution
- Turn on with a reed-sensor (using a magnet). The reed sensor is just a real switch closed by magnet.
- When turned on, the power has to be keept on by the ESP closing a connected MOSFET. This MOSFET is in parallel to the reed sensor.
- To turn off, the ESP just has to set the GPO pin for the MOSFET down. This could be triggered by a special RFID sensor.
We also should signalize turning on/off by a beep sequence.