Too big voltage coming from DR55 unit to MCU #3
Description
According to schematics you are sending VCC from unit to MCU. It could be more than 5v, so it is better to add regulator like LD1117.
We achieved good results with LD33 regulator between white wire and +5v on our Arduino. But we had to add regulator for the whole scheme for 6 volts to use it with AC adapter.