Hello,
I’m an automation engineer and research worker. I’m specialized in HVAC control systems (more then 35 years experience), BMS, Switching power supplies, Arduino, Bluetooth, ZigBee, GPS systems and Home automation.
I have made a similar project project - a collar with two PSB's: ZigBee or Bluetooth, 1MB additional SRAM, UART and SPI interface in the right PCB and GPS receiver, gyroscope and accelerometer in the left. The dimensions of each PCB are 25.3x28.2 mm. You can visit also my short profile portfolio.
Unfortunately freelancer.com don't give me an option to upload images or attach them in my bid.
My best regards