Consumer electronics are a goldmine of useful components — if they can be hacked. Fitness trackers are a great example, because they usually contain a handful of sensors, Bluetooth, a display, a microcontroller, and a battery, all in a tiny package. What you do with all of that is up to you, but Curt White got especially creative and repurposed a fitness tracker as an EEG mind-reading headset.
For this project, White chose a B20 Fitness Tracker that you can pick up for just $35, and packed into that wristband is a whole host of goodies. There is an Arm Cortex-M4 processor, Bluetooth, an OLED display, accelerometer, optical HR sensor, and vibration motor. But, the coup de grâce is an ADS1292 bioimpedance sensor, which provides that biological wave sensing that is the key to this build.
Once the B20’s case has been cracked open, prepping the board for programming is as simple as soldering wires onto the four PCB test pads. Normally, the bioimpedance sensor is used to provide ECG (electrocardiogram) heart monitoring. White’s project instead places the sensor on a headset, so that it can use EEG (electroencephalogram) to read brain waves. Those readings are then analyzed with a neural network to determine if the wearer is in a state of relaxation or concentration. The sensor can only provide rough readings, but the neural network could theoretically be used for more specific analyses.