This is schematic of new version of my device. The prototype was just a shield for Arduino Uno, new version is standalone. The microcontroller is based on Arduino Mini with Atmega328P-AU.

ICSP and FTDI headers are included to burn Arduino bootloader and upload sketches. UART can be switched between FTDI header and HM-10 module via two jumpers.

It's designed for 3.3V HM-10 module without logic level converter or voltage regulator, however I included header for 5V version with level converter (which I'm sure that works).