Speak With Your Eyes: Build a Mind-to-Words (M2W) Interface

What if a person who cannot speak could still express basic needs using only eye blinks? In this project, we explore the world of Human-Computer Interaction (HCI) and Brain-Computer Interface (BCI) by creating a system that translates eye blinks into spoken words.

Mind to Words (M2W) is a communication system designed to help ALS patients and individuals with limited voluntary movement interact with their environment. Using the Neuro PlayGround (NPG) Lite—a powerful, wireless bio-potential sensor—we capture tiny electrical signals from the eyes (EOG) to control a speech-assistance application.

This is a completely "hands-free" communication tool. By capturing these bio-potential signals, users can hover through a menu of six essential needs—Water, Food, Washroom, Help, Outing, and Television—and select them to be spoken aloud simply by blinking. This low-cost assistive technology provides a vital voice to those who need it most, turning biopotential signals into meaningful human connection

Hardware:

1. 1 x NPG Lite
2. 1 x Vibz Playmate
3. 3 x BioAmp Snap Cables
4. 3 x Gel electrodes
5. 1 x Nuprep skin preparation gel (Optional )
6. 1 x Alcohol swab
7. 1 x Laptop

Tip: You can get everything in the Ninja Pack From ROBU.IN, Tindie, Upside Down Labs online store.

Software

1. NPG Lite Flasher web Application
2. M2W Web Application
3. Chromium-based browser (Google Chrome, Brave, or Microsoft Edge) for the M2W app.

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 (NPG) Lite is now available on ROBU.IN, Tindie, Upside Down Labs online store.

Learn more about NPG Lite on our documentation.

1. Apply a small amount of Nuprep gel (optional)
2. Gently rub on electrode placement areas
3. Clean with alcohol swabs

This removes oil and dead skin, improving signal quality.

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

Connect 3 BioAmp Snap Cables to

1. Positive of Channel 1 to A0P
2. Negative of Channel 1 to A0N
3. Reference cable to REF

Measuring EEG using Gel electrodes:

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

Before connecting the device to the software, we first need to properly power the NPG Lite.

1. Connect the battery cable properly to the NPG Lite board to power the device wirelessly. Make sure the connector is securely attached before starting.
2. Turn ON the NPG Lite board by switching the ON/OFF button to the ON position. The board is now ready to connect and use.

1. Connect NPG Lite to your computer via USB
2. Open NPG Lite Web Flasher.
3. Click Connect → Select USB JTAG
4. Click Get from GitHub → Select “BCI-Blink-BLE”
5. Flash firmware

Once done, disconnect USB — the device will work wirelessly.

1. Open the M2W Web app in chrome/brave: https://upsidedownlabs.github.io/M2W/
2. Turn on Bluetooth (Note: Just turn on Bluetooth and donot manually connect NPG Lite to bluetooth)
3. Click Connect to scan for BLE devices.
4. In the dialog box, select ESP32C6_EEG (your NPG Lite device).
5. Once connected, electrode signals are streamed in real-time.
6. Try blinking:
7. Double blink: Hover menu items
8. Triple blink: Speak/select the option

The system detects blink patterns:

1. Single Blink: No action
2. Double Blink: Navigate through the menu
3. Triple Blink: Select the option and speak it out loud

1. Perform strong, deliberate blinks rather than natural eye flutters.
2. Sit still, keeping your head steady and jaw relaxed to avoid muscle artifacts.
3. Stay at least 5 meters away from heavy appliances (microwaves, fluorescent lights) to reduce electrical noise.
4. Ensure firm electrode contact with the skin.

1. If the signal is poor, clean the skin, reapply gel, and check placement.
2. Verify the BCI-BLINK-BLE firmware is flashed and select ESP32C6_EEG when pairing.
3. Keep the NPG Lite within 10 meters of your system.
4. If the browser won't scan for Bluetooth, type chrome://flags in your URL bar, enable Web Bluetooth, and restart the browser.

1. Current uses include assistive communication, hands-free accessibility, and BCI/HCI education.
2. Future upgrades aim to include machine learning classification, custom blink patterns, free-form text-to-speech, and multi-user profiles.