ECG GSR Click Board™

Product Code: MIKROE-4500

How Does The ECG/GSR Click Board™ Work? The ECG/GSR Click Board™ as its foundation uses the AS7030B, a vital sign sensor based on Photoplethysmography (PPG) and Electrocardiogram (ECG) operations from AMS-AG. These two popular methods are suitable for heart rate monitoring (HRM) and heart rate variability (HRV), which measure the pulse rate by sampling light modulated by blood vessels that expand and contract as blood pulses through them. The ECG is the reference for any measurement of the bio-potential generated by the heart. This vital sign sensor features a low noise analogue front end, a single device integrated optical solution, and a synchronous demodulator. It consists of two 527nm green LEDs and one 940nm IR LED. The built-in infrared emitter and dedicated photodiode enable easy integration of proximity function. Besides the HRM and SpO2, the AS7030B is an optical measurement system for GSR (galvanic skin resistivity) and skin temperature obtained via an external temperature sensor connected to an onboard header labelled NTC.

The ECG/GSR Click Board™ communicates with MCU using the standard I2C 2-Wire interface that supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation. Also, it uses two additional pins, the INT pin of the mikroBUS™ socket, used as an interrupt, and the EN pin, routed on the CS pin of the mikroBUS™ socket, used to put the AS7030B into Normal operation mode or in a Shutdown. The AS7030B does not require a specific Power-Up sequence but requires a supply voltage of 3.8V to work correctly. Therefore, the Click board™ uses a low dropout linear regulator AP7331 from Diodes Incorporated, providing a 3.8V out of 5V mikroBUS™ rail. The ECG/GSR Click Board™ consists of two input channels routed to the 3.5mm jack connectors labelled as ECG and GSR, to which a 1m long ECG/EMG cable connects the electrodes to the appropriate Click board™ securely. The two electrode holders consist of a metal piece with a dent in the middle that perfectly fits the rivets on the electrodes. The contact with the measurement Click board™ remains good and secure, while mounting the cable's electrodes is simple and easy. The ECG/GSR Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the I2C communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development. SPECIFICATIONS Type Biometrics Applications Can be used for remote medical diagnostic equipment applications, such as disposable patches for blood oxygen saturation (SpO2) and electrocardiogram (ECG) measurement. On-board modules AS7030B - vital sign sensor based on Photoplethysmography (PPG) and Electrocardiogram (ECG) operations from AMS-AG Key Features The low-noise analogue front end, synchronised PPG, ECG and GSR acquisition, blood pressure measurements, good HRM quality, temperature sensing using NTC, long operating period, and more. Interface I2C Compatibility mikroBUS Click board size L (57.15 x 25.4 mm) Input Voltage 3.3V or 5V PINOUT DIAGRAM This table shows how the pinout of the ECG/GSR Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns). Notes Pin Pin Notes NC 1 AN PWM 16 NC NC 2 RST INT 15 INT Interrupt Enable EN 3 CS RX 14 NC NC 4 SCK TX 13 NC NC 5 MISO SCL 12 SCL I2C Clock NC 6 MOSI SDA 11 SDA I2C Data Power Supply 3.3V 7 3.3V 5V 10 5V Power Supply Ground GND 8 GND GND 9 GND Ground ONBOARD SETTINGS AND INDICATORS Label Name Default Desc