This is an ECG (or EKG) machine on a Click board™. It measures the electrical activity of a beating heart through electrodes taped to the skin. The board requires little setup, and the final measurement results can be displayed as an Electrocardiogram using a free Windows app.
To start recording ECG you will need:
Of course, you will also need a target board with an MCU with at least a 10-bit ADC (preferably powered from an external battery).
The three electrodes are connected to your left shoulder, right shoulder, and to the left side of the abdomen (below the heart). The last one can also alternatively be fitted on the left leg.
The electrodes are connected to the board with a cable that plugs into the onboard 3.5mm phone jack.
See the docs page for more detailed instructions.
Circuit design: amplifying and filtering the raw signal
By the time it reaches skin surface, the electrical signal from the heart becomes faint. Only few miliVolts. This weak signal is also obstructed by muscle activity from the rest of the body.
Another source of noise is the electromagnetic interference from the environment (the body can act as an antenna).
But the pattern of a beating heart is fairly predictable. This allows us to design circuitry that properly amplifies and filters the electrical signal to get the desired output.
ECG Click has a 7 block design. It comprises ESD, overvoltage and overcurrent protection (protecting both the hardware and the person), a pre-amplifier and amplifier, two high-pass filters, a low-pass filter, and a DRL circuit.
Plot your heart beat
MikroPlot is a free data visualization tool (Windows) that can be used to generate an ECG.
The graph is generated from data sent from the MCU (ADC values from ECG Click input + time stamp). A UART-USB connection is required.
See the learn.mikroe.com article for more information.
No reviews yet.