A $10 GPS, a battery pack, a charge controller, and a few user interface parts like an OLED screen and a keyboard. In addition, there’s an SD card to store messages.

[Usmar A. Padow] put together an Arduino Uno, SD card, four line character LCD, and PS/2 keyboard. but he’s also included alternative options to go without an LCD screen by using a computer ...

The Gesture Keyboard is a device that translates gestures into letters. It’s made by an Arduino Pro Micro, an HC-06 module for Bluetooth communication, and an MPU-6050 accelerometer.

The Arduino then sends signals to a Raspberry Pi that acts as a network interface to OpenAI's GPT-3 API. When GPT-3 responds, Ghostwriter noisily types the AI model's output onto paper automatically.