Pop Bubbles With Your Mind (EEG) using Neuro PlayGround Lite

Ever imagined controlling something on your laptop screen just with your mind?

That’s right! No mouse, no keyboard, just pure focus.

To make this possible, we're recording EEG signals from the prefrontal cortex region of the brain using Neuro PlayGround Lite.

Kudos to Ritika Mishra for building this project.

But before moving forward, let's get familiar with BCI and EEG.

What is electroencephalography (EEG)?

Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the International 10–20 system.

What is Brain-Computer Interface (BCI)?

A brain-computer interface (BCI), sometimes called a brain-machine interface (BMI), is a direct communication link between the brain's electrical activity and an external device, most commonly a computer or robotic limb.

How does this game work?

This demo showcases a brain-computer interface (BCI) application that utilizes EEG (electroencephalography) signals to operate an interactive bubble-popping game in a web browser. The system identifies beta wave activity (12–30 Hz), indicating concentration and attention levels. Bubbles appear and pop as the user maintains focus, but they cease to pop when concentration decreases.

About Neuro PlayGround (NPG) Lite:

Neuro PlayGround (NPG) Lite is a compact Adafruit Feather form factor, a 3-channel wireless biopotential signal amplifier designed for EMG, ECG, EOG, and EEG recording.

It offers Wi-Fi, Bluetooth, Zigbee, and Thread connectivity, along with patient protection, LEDs (User LED, charging LED, six addressable RGB LEDs), buttons (Reset and user button), LiPo battery charging, and USB-C with ESD protection. Its lightweight and user-friendly design makes it perfect for research, education, and wearable applications.

Neuro PlayGround Lite will be launched on CrowdSupply. Subscribe now to never miss out on any updates.

https://www.crowdsupply.com/upside-down-labs/neuro-playground-lite

Step 1: Skin Preparation

Start by applying Nuprep Skin Preparation Gel to the areas where the electrodes will be placed. The Nuprep Gel gently exfoliates the top layer of the skin, removing dead cells and oils that can interfere with signal transmission.

After rubbing the gel in a circular motion for a few seconds, clean the area using an alcohol swab or wet wipe. This step ensures that your skin is ready for the best possible electrode contact, think of it as polishing the lens before taking a photo!

What is Nuprep Gel?

Nuprep is a mildly abrasive, highly conductive gel that improves electrode contact by reducing skin impedance. It's safe, effective, and causes minimal skin irritation.

Step 2: Connecting BioAmp Cables

Once your skin is prepared, it’s time to connect BioAmp Snap Cables.

Connect 3 BioAmp Snap Cables to

• Positive of Channel 1 to A0P
• Negative of Channel 1 to A0N
• Reference cable to REF

Step 3: Electrode Placements

Let's understand the electrode placements before moving forward in this project. For recording EEG from the prefrontal cortex part of the brain, you have to place the electrodes on your forehead, specifically between Fp1 and Fp2 (refer to the International 10-20 system for recording EEG)

What is the International 10-20 system for recording EEG?

It is an internationally recognized method to describe and apply the location of electrodes in the context of an EEG exam or voluntary lab research. This method was developed to maintain standardized testing methods, ensuring that a subject's study outcomes (clinical or research) could be compiled, reproduced, and effectively analyzed and compared using the scientific method.

Measuring EEG using Gel electrodes:

• Connect the BioAmp Cable to gel electrodes,
• Peel the plastic backing from the electrodes.
• Place the cable connected to A0P between the Fp1 and Fp2 positions
• Place the cable connected to A0N on the bony part behind the earlobe on one ear.
• Place REF on the bony part behind the earlobe of the other ear.

Step 4: Uploading the Firmware

To get your NPG-Lite ready for action, upload the latest firmware using the Arduino IDE, to do this:

• Power up the Neuro PlayGround Lite (NPG Lite) by flipping the ON/OFF switch and connecting your NPG device to your laptop/PC with a Type-C Cable.
• Open the Chords Arduino Firmware folder on Github:https://raw.githubusercontent.com/upsidedownlabs/Chords-Arduino-Firmware/refs/heads/main/NPG-LITE-BLE/NPG-LITE-BLE.ino
• Copy your board's firmware sketch from the GitHub folder - this ensures you're always working with the latest version as updates roll out frequently.
• Launch the Arduino IDE and directly paste it into a new Arduino sketch window.
• Install the esp32 board from the board's menu. (Note: You don’t need to install Arduino-ESP32 just install esp32)
• Install the required libraries, such as Adafruit NeoPixel. The IDE will usually prompt you to install any missing ones, just click “Install” when prompted.
• In the Arduino IDE:
• Go to Tools → Board and select ESP32 → ESP32C6 Dev Module
• Once your board is selected and libraries are installed, click the Upload button.

After the upload completes, remove the cable as your NPG Lite is ready to send EEG and other biopotential data wirelessly.

Step 5: Running the Web Interface

Now download the GitHub repository of the project, the link of which is given below.

GitHub Repository: https://github.com/Ritika8081/Brain_Bubbles

Extract the downloaded folder, open it, and click on the index.html file.

The web interface will be opened and you will see a blue circle or bubble generator displayed at the center of the page along with several control buttons at the bottom, such as Connect, Disconnect, Start Stream, Stop Stream, and a slider to set the Beta threshold. On the top right corner, you can visualize different band power values of all the brainwaves with respective percentages.

To start playing the game,

• Turn on the Bluetooth of your laptop
• Click on the Connect button
• Select your board from the list
• Set a Beta Threshold value which is by default set at 0.40
• Click on the Start Stream button.

Now the game setup is complete and when you focus, your beta brainwave activity increases and if it exceeds the threshold you have set then bubbles will start rising from the bubble generator. As soon as you lose focus and your beta activity drops below the threshold, the bubbles will stop, providing intuitive neurofeedback on your focus levels.

Step 6: Conclusion

This was just a demonstration of how Neuro PlayGround Lite can record, filter, and process single-channel EEG signals. Now imagine what could be possible when we record three channels of biopotential signals (EEG, EMG, EOG, ECG).

This is just the beginning. We are already working on creating much more interesting brain-computer interfaces.

The possibilities are endless. Drop your feedback in the comments.

Need help? Reach out at support@upsidedownlabs.tech

Step 7: Troubleshooting

Getting an accurate EEG signal is very crucial for this project to work properly. Please check the link below for the tips for best signal acquisition: https://docs.upsidedownlabs.tech/guides/troubleshoot/tips/index.html

In case a weak EEG signal is detected, then ensure there is good electrode contact with the skin surface and you have prepared the skin using nuprep skin preparation gel properly.

If you face any issues with the Bluetooth connection, then restart NPG Lite and try to reconnect.