Recent versions of the Raspberry Pi support USB on-the-go (USB OTG), which allows them to impersonate USB devices such as keyboards, thumb drives, and microphones. To take advantage of this, I made an open-source web app that turns my Pi into a fake keyboard. I call it Key Mime Pi.

This post demonstrates how Key Mime Pi works and how you can build one for yourself.

Demo

What you’ll need

• A Raspberry Pi that supports USB OTG:
  • Raspberry Pi 4 (all variants)
  • Raspberry Pi Zero W
  • Raspberry Pi A and A+ (verification needed)
    • This source claims that early Pis support USB OTG, but I have not tested these devices personally.
• Raspberry Pi OS (aka Raspbian)
  • Stretch or later
• A USB cable
  • For the Pi 4: USB-C to USB-A (Male/Male)
  • For the Pi Zero W: Micro-USB to USB-A (Male/Male)

Install Raspberry Pi OS Lite

To begin, install Raspberry Pi OS lite (formerly known as Raspbian) on a microSD card.