The trezor is a hardware bitcoin wallet made by satoshilabs used to secure online transactions. The security reside in the fact that the private key used to sign a transaction never leave the device.
The raspberry pi zero is a very cheap and small but yet powerful computer. You can buy one for about 5$. It is used on numerous projects by ton of developers and hobbyists around the world.
Features:
- Low cost parts
- Easy to build
- Use the original trezor code. Only a thin layer is used to adapt the code to the pi zero Linux platform.
- All code modifications are open source, like the original trezor code.
- 100% Compatible with trezor web wallet to perform transactions.
- Use the hardware random number generator of the raspberry pi for more security.
- Can be very secure if you use a pass phrase (see security section below)
- Support small OLED display and/or display via HDMI output
The detailed instructions are on my site at https://www.pitrezor.com