Shopping list for Specter-DIY
Here we describe what to buy, and in assembly.md we explain how to put it together and a few notes about the board - power jumpers, USB ports etc.
Main part of the device is the developer board:
- STM32F469I-DISCO developer board (i.e. from Mouser or Digikey)
- MiniUSB cable
- Standard MicroUSB cable to communicate over USB
Check out the assembly video on youtube
We are currently working on an extension board that includes a smartcard slot, QR code scanner, battery and a 3d printed case, but it doesn't include the main part — discovery board that you need to order separately. This way supply chain attack is still not an issue as the security-critical components are bought from random electronic store.
You can start using Specter even without any extra components, but you will be able to communicate with it only over USB. In this case it's not airgapped so you lose an important security property.
For QR code scanner you have several options.
Option 1. Recommended. Resonably good scanner from Waveshare (40$)
No soldering required, but if you have soldering skills you can make the wallet way nicer ;)
Option 2. Very nice scanner from Mikroe but pretty expensive (150$):
Option 3. Any other QR scanner
You can find some cheap scanners in China. Their quality is often not that great, but you can take a chance. Maybe even ESPcamera would do the job. You only need to connect power, UART (pins D0 and D1), and trigger to D5.
Option 4. No scanner.
Then you can only use Specter with USB.
Unless you build your own communication module that uses something else instead of QR codes - audiomodem, bluetooth or whatever else. As soon as it can be triggered and send the data over serial you can do whatever you want.
If you add a tiny powerbank or a battery & power charger/booster, your wallet becomes completely self-contained ;)