Right Leg Drive
I designed the Driven Right Leg circuit on the board to get ride of common-mode noise.
A Driven Right Leg Circuit or DRL circuit is an electric circuit that is often added to biological signal amplifiers to reduce Common-mode interference.
Biological signal amplifiers such as ECG (Electrocardiogram) EEG (Electroencephalogram) or EMG circuits measure very small electrical signals emitted by the body, often as small as several micro-volts (millionths of a volt).
Unfortunately, the patient's body can also act as an antenna which picks up electromagnetic interference, especially 50/60 Hz noise from electrical power lines.
This interference can obscure the biological signals, making them very hard to measure.
Right Leg Driver circuitry is used to eliminate interference noise by actively cancelling the interference.(from WIKIPEDIA)
Shown in the image above, the mechanism bechind Driven Right Leg Circuit is similar to how an active noise cancelling headphone works.
The circuit collect all common-mode noise, then invert the signal, push it back to human body.
As result, the noise is canceled.
The development board is compatibility with various of setups.
- Raspberry Pi Family
- Beaglebone Family
- Arduino Feather Family
- Any machine running Linux with SPI port
- Wet electrodes
- Active dry eletrodes
It also has I2C port which can connect IMU, temperature sensor and so on.
The ADS1299 also can be replaced by ADS129X and ADS119X family.