SeedSigner
DIY Bitcoin hardware wallet:
- Raspberry Pi Zero (or compatible) + camera + small screen.
- Boots from microSD running SeedSigner image.
- Stateless: no seed stored on device. User enters seed each session via dice / QR / hand-typed words.
Hardware (DIY)
- Raspberry Pi Zero W (~$10).
- Camera Module 1.3 / 2.1 (~$25).
- Waveshare 1.3" screen (~$20).
- 4 GPIO buttons.
- microSD with SeedSigner image.
Total: ~$60 in parts, plus 3D-printed case.
Operation
- Boot SeedSigner from microSD.
- Enter seed via:
- Dice rolls (entropy → seed).
- Manual word entry.
- SeedQR scan (encoded BIP39 mnemonic).
- Use as airgap signer for PSBT (QR transport).
- Power off → seed wiped from RAM.
No persistent storage of seed = no risk of physical seizure revealing keys.
Compatible wallets
- Sparrow Desktop.
- Specter Desktop.
- Nunchuk.
QR transport: animated QR for PSBT in/out.
Use cases
- DIY enthusiasts wanting open hardware.
- High-security applications: no firmware backdoors possible (you build it).
- Educational: understand how HW wallets work.
Compared to commercial
| Aspect | SeedSigner | Commercial HW |
|---|---|---|
| Cost | $60 DIY | $50-500 |
| Auditability | Full (you built it) | Trust manufacturer |
| Convenience | Lower (boot every session) | Higher |
| Permanent storage | None (stateless) | Encrypted internally |
| Maintenance | DIY | Vendor support |
Limitations
- Slower signing (boot time + manual seed entry).
- No tamper-evident hardware — Raspberry Pi has no SE.
- Camera quality affects QR scan reliability.