The MAXREFDES73# reference design from Maxim Integrated is a wearable, mobile galvanic skin response (GSR) system featuring the MAX32600 wellness measurement microcontroller. This battery-powered platform takes high-precision AC impedance measurements while consuming minimal power. The MCU combines an ARM Cortex-M3 32-bit core operating at up to 24 MHz with multiple high-performance analog peripherals. Analog features include a 16-bit ADC with programmable gain amplifier (PGA), two 12-bit DACs, and a 16-channel multiplexer along with classic digital features such as 256KB of flash memory, 32KB of SRAM, and a 2KB instruction cache.

The reference design provides a high-performance and flexible development platform that can serve as a foundation for fitness and medical measurement applications, especially those that need galvanic skin response measurements.

Shaped as a wrist-worn unit, it is powered by a LIR2032 rechargeable coin battery. A free mobile application for Android devices provides the interface, communication takes place over a Bluetooth low-energy (BLE) wireless link. Design files and source code are available to get you up and running quickly to test your homebrew sports watch.