Maxim Integrated's MAXREFDES73# reference design 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 MAX32600 microcontroller features the industry-standard ARM^® Cortex^®-M3 32-bit RISC CPU that operates at up to 24 MHz, while integrating multiple high-performance analog peripherals. Analog features include a 16-bit ADC with PGA, two 12-bit DACs, and a 16-channel multiplexer along with classic digital features such as 256 KB of Flash memory, 32 KB of SRAM, and a 2 KB instruction cache.

The reference design provides a high-performance and flexible development platform, which is a foundation for many fitness and medical measurement applications, especially galvanic skin response measurement. The reference design arrives as a wrist-worn unit, powered by a LIR2032 rechargeable coin battery. A mobile application program for devices for Android™ provides the interface and is free for download. The device communicates with a device for Android though a Bluetooth® low-energy wireless interface. Test results, hardware files, and firmware source code provide complete documentation for the design. The complete wrist-worn unit is available for purchase.

GSR measurement detects human skin impedance under different situations. A variety of events affect the skin impedance of a human body, such as changes with the ambient environment, stress from a sudden event, and sweating from physical exercises. GSR devices can be used in medical treatment, lie detection, and wellness monitoring.