Detecting Eye Blink Using Electrooculography — BCI
What if you can control smart devices using your mind or brain waves ? Isn’t it sounds like magic, No its not magic, its just one of the new emerging technology between us. It so called Brain Computer Interface.
Using BCI technology you can actually build a lot of interesting projects, For ex- Playing chess using brain waves, Controlling a led using eye, Controlling a prosthetic arm and lot more. So you might think that what exactly the BCI is ?
What’s Brain Computer Interface ?
Brain–computer interfaces (BCIs) measure electrical/neural activity of our brain, extract features from that activity, and convert those features into outputs that replace, restore, or improve human functions.
BCIs may replace lost functions, such as speaking or moving. They may restore the ability to control the body, such as by stimulating nerves or muscles that move the hand. BCIs can also enhance function, like warning a sleepy driver to wake up.
Different techniques are used to measure brain activity for BCIs. Most BCIs have used electrical signals that are detected using electrodes placed invasively within or on the surface of the cortex, or noninvasively on the surface of the scalp [electroencephalography (EEG)].
Reading the Bio-Signals
To record electrical activity generated by the brain, We don’t have to open skull to place sensors. It can be much easier than that — we can simply record the electrical data from sensors (electrodes) by placing them on the scalp surface. Since the electrical signals are very small, the recorded data is digitized and sent to an amplifier to amplify the signal to integrate with microcontroller ( Arduino ).
Using Electrooculography To Detect Eye Blink
I have been working on a project of detecting eye blink using Electrooculography ( Electrooculography is used to record eye movements, Its a techniques for measuring difference in electrical charge between the cornea and retina ). The purpose of the project was to detect the eye blink and make buzzer sound on every blink as output.
Making the project
Electrodes Placement For Electrooculography
EOG electrodes are placed using a conductive gel, quality of electrodes may vary the coming data, So it is recommended to use high quality electrodes, by cleaning them using isopropanol alcohol.
Things I have used in the project
Circuit Diagram
The circuit diagram below includes the Operational Amplifier that I used with microcontroller to take signal from sensors ( electrodes ) and processed to give the output.
Role of Operational Amplifier
The signal that comes from our brain is of very low amplitude ( small signal ) so we use instrumentational amplifier to amplify the signal. The signal then passed to the different types of filters ( Low pass/High pass or Band pass ) that help us to reduce the noise and increase the quality of signal. The amplified signal then sent to microcontroller for the signal processing.
Microcontroller ( MCU )
Arduino is very common MCU between us, So I though it right to use Arduino as microcontroller for my project. The role of Arduino in my project was to receive signal from Instrumentational Amplifier and processed it according to the code ( Instructions ) and to give the output.
Making the buzzer sound as output
I used a 5v small buzzer as output for this project, So whenever the amplifier receives the EOG signal from sensors ( electrodes ), Arduino processed it to give output by making the buzzer sound.
Conclusion
Brain Computer Interface is really a nice technology to work on. BCI is having great advantages like replacing lost functions and restoring the ability to control the body. Using BCI technology people are trying to record their night dreams. Neuralink created a project where they have tried to play pong game to monkey. So I think this is really a vast field and it have very good scope in future, because we will do very unrealistic projects or will solve real world problems using BCI technology in future .
Bio-Amp EXG Pill
BioAmp EXG Pill is a small and elegant Analog Front End (AFE) board for BioPotential signal acquisition that you can use with any 5v Micro Controller Unit (MCU) with an ADC.
I have personally used this module and its really great for people who just wanna get started with Brain Computer Interface or who wanna record Bio-Signal like EEG, EOG, EMG and ECG.
Special Thanks To Upside Down Labs
Upside Down Labs provide me an opportunity to work on their Bio-Amp EXG Module, I would say that my journey of learning BCI Technology starts from there. Thanks UDL for this great opportunity & I think it become very easy for me to learn this technology using your module. Thanks Again.
