BioAmp EXG Pill is a small, powerful analog-front-end (AFE) biopotential signal-acquisition board that can be paired with any microcontroller unit (MCU) or single-board computer (SBC) with an analog-to-digital converter (ADC) such as Arduino UNO & Nano, Espressif ESP32, Adafruit QtPy, STM32 Blue Pill, BeagleBone Black, and Raspberry Pi Pico, to name just a few. It also works with any dedicated ADC, like the Texas Instruments ADS1115 and ADS131M0x, among others.

BioAmp EXG Pill is capable of recording publication-quality biopotential signals like ECG, EMG, EOG, and EEG, without the inclusion of any dedicated hardware or software filters. Its small size allows easy integration into mobile and space-constrained projects, and its powerful noise rejection makes it usable even when the device is close to the AC mains supply. Any 1.5 mm diameter wire can be used as a strain-relieving electrode cable, making it very cost-effective in comparison to the other available.

The BioAmp EXG Pill can be used in a variety of ways, the YouTube video below shows a potential way of using v0.7 of BioAmp EXG Pill.

A lot has improved in terms of interference rejection and flexibility from v0.7 to v1.0 of the BioAmp EXG Pill. The YouTube video below shows the ECG, EMG, EOG, and EEG recording using v1.0b of device.

Electromyography (EMG)

Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is also used as a diagnostic procedure to assess the health of muscles and the nerve cells that control them (motor neurons). EMG results can reveal nerve dysfunction, muscle dysfunction, or problems with nerve-to-muscle signal transmission. The images below show an EMG wave recorded with BioAmp EXG Pill and the electrode placement for the recorded EMG respectively.

Checkout the Electromyography (EMG) Walkthrough project update for information about EMG filtering, envelop detection, servo control, and LED-bar control, as well as an exciting project demo that relies on EMG data recorded with BioAmp EXG Pill.

Electrocardiography (ECG)

Electrocardiography (ECG) is the process of producing an electrocardiogram (ECG or EKG). It is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). The images below show electrode placement for lead 1 ECG recording, an ECG wave recorded with BioAmp EXG Pill and electrode placement for hand ECG/EKG recording respectively.

Checkout the Supportive Technology project update for information about ECG filtering and heart-beat detection, and more on ECG recording, with BioAmp EXG Pill.

Electrooculography (EOG)

Electrooculography (EOG) is a technique for measuring the corneo-retinal standing potential that exists between the front and the back of the human eye. The resulting signal is called EOG. Common electrode placement for vertical & horizontal EOG recording is shown in the image below.

To measure eye movement, pairs of electrodes are typically placed either above and below the eye or to the left and right of the eye. If the eye moves from the center position toward one of the two electrodes, this electrode "sees" the positive side of the retina, and the opposite electrode "sees" the negative side of the retina. Consequently, a potential difference occurs between the electrodes. Assuming the resting potential is constant, the recorded potential is a measure of the eye’s position. The images below show electrode placement for vertical EOG recording, an EOG signal recorded with BioAmp EXG Pill and electrode placement for vertical EOG respectively.

Checkout the Electrooculography (EOG) Walkthrough project update for information about EOG filtering and eye-blink detection, and more on EOG recording, using BioAmp EXG Pill.

EEG

Electroencephalography (EEG) is an electrophysiological monitoring method to record electrical activity on the scalp. During the procedure, electrodes consisting of small metal discs with thin wires are pasted onto your scalp. The electrodes detect tiny electrical charges that result from the activity of your brain cells which are then amplified to appear on the computer screen. It is typically non-invasive, with the electrodes placed along the scalp. The images below show an EEG wave recorded with BioAmp EXG Pill and the electrode placement for the frontal cortex EEG recording respectively.

Checkout the Electroencephalography (EEG) Walkthrough project update for information about EEG filtering, and more on EEG recording, with BioAmp EXG Pill.

Your One-Stop Shop for Biopotential Amplification

BioAmp EXG Pill is perfect for researchers, makers, and hobbyists looking for novel ways to sample biopotential data. It can be used for a wide variety of interesting biosensing projects, including:

• AI-assisted detection of congestive heart failure using CNN (ECG)
• Heart-rate variability calculation to detect heart ailments (ECG)
• Prosthetic arm (servo) control (EMG)
• Controlling a 3DOF robotic arm (EMG)
• Quantitative analysis of physical therapy for palsy (EMG)
• Real-time game controllers (EOG)
• Blink detection (EOG)
• Capturing photos with a blink of an eye (EOG)
• Controlling LEDs via brain waves (EEG)
• Patient monitoring

…And many more examples.

Features & Specifications

• Input Voltage: 4.5 - 40 V
• Input Impedance: 10^12 Ω
• Compatible Hardware: Any ADC input
• Biopotentials: ECG, EOG, EMG, and EEG (configurable Band-Pass)
• No. of channels: 1
• Electrodes: 2 or 3 (configurable)
• Wearable: Yes
• Dimensions: 25.4 x 10.0 mm
• Designed for Use With a Carrier Board: Yes
• Open Source: Hardware + Software

Designed to Support a Variety of Applications

BioAmp EXP Pill’s elegant design allows it to be used in three ways:

• Its pin-header holes allow you to solder (berg strip) pin headers for easy use with a breadboard
• Its castellated holes allow you to solder BioAmp EXG Pill directly onto a custom PCB that requires biopotential-amplification capabilities
• Its electrode holes allow you to use any 1.5 mm diameter wire as an electrode cable with minimal strain

Board-Layout Diagrams

Front

Back

Software

To help with signal processing and cleaning, you can use the Arduino sample sketches listed below:

You an EXG Explorer or a Neuroscience Ninja?

Comparisons

Schematic

Click to enlarge

Support & Documentation

We are enthusiastic about open hardware and open source software! You can find our extensive, open-source, CERN- and MIT-licensed hardware and software documentation in our GitHub Repository. And, if you have questions, you can reach us using the Ask a technical question form below.

Manufacturing Plan

After contacting multiple PCB-fabrication and SMT-assembly houses in India, we identified likely manufacturing partners and had them produce a batch of prototype PCBs. The quality was good, and we intend to work with them for this production run. We also contacted a few manufacturers in China, and we will stay in contact with them as a possible backup option.

Fulfillment & Logistics

After testing and packaging the production batch of BioAmp EXG Pill boards, we will send them on to Crowd Supply’s fulfillment partner, Mouser Electronics, who will distribute them to backers worldwide. You can learn more about Crowd Supply’s fulfillment service under Ordering, Paying, and Shipping in their guide.

Risks & Challenges

Despite the supply-chain difficulties that continue to plague the electronics industry, we see very little risk for BioAmp EXG Pill. This is due, in large part, to the fact that we have already procured what we believe to be a sufficient quantity of the primary IC upon which our design relies.