The SeedSigner is an air-gapped Bitcoin signing device you can actually verify: open-source hardware and software, off-the-shelf parts, no memory for your seed. We print and assemble it in Germany — fully built and tested, as a DIY kit for half an hour at the kitchen table, or as a bare case for the parts you already own.
Every assembled device ships without a microSD card and without the software image — on purpose. You download SeedSigner from github.com/SeedSigner, verify the signature and flash your own card, so the chain of trust ends with you, not with us.
 SeedSigner+ |
 Rugged Pill |
 Aluminium edition |
 DIY kit |
 OpenPill case (one colour) |
 OpenPill case (two-tone) |
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|---|---|---|---|---|---|---|
| What you get | Fully assembled device, tested | Fully assembled device, tested | Fully assembled device, tested | All parts, you assemble (≈ 30 min, no soldering) | Case only — for your own Pi, display and camera | Case only — for your own Pi, display and camera |
| Display | Large display — QR codes and seed words readable without glasses | 1.3″ Waveshare, 240 × 240 | 1.3″ Waveshare, 240 × 240 | 1.3″ Waveshare, 240 × 240 (included) | fits 1.3″ Waveshare | fits 1.3″ Waveshare |
| Controls & power | D-pad with clear click, USB-C, spring-loaded SD slot | Joystick with threaded-insert head + TPU button, micro-USB | Joystick with threaded-insert head + TPU button, micro-USB | Joystick with threaded-insert head + TPU button, micro-USB | Threaded insert fitted, TPU button included | Threaded insert fitted, TPU button included |
| Case | Orange pill design, 3D-printed | Thick-walled Rugged Pill, black/orange — for backpack and travel | Machined aluminium — heavy, solid, dissipates heat | OpenPill, silver/orange or black/orange | OpenPill in one colour: black, silver, orange (blue/green to order) | OpenPill, body and lid in two colours |
| Electronics | Pi Zero (no Wi-Fi/BT), display, camera — built in | Pi Zero (no Wi-Fi/BT), display, camera — built in | Pi Zero (no Wi-Fi/BT), display, camera — built in | Pi Zero 1.3 with header soldered, display, camera + cable — in the box | not included | not included |
| microSD & software | you flash it yourself | you flash it yourself | you flash it yourself | you flash it yourself | — | — |
| Best for | Everyday use, larger hands, tired eyes | A device that travels | The premium feel, a device that stays on the desk | Knowing exactly what is inside — and saving money | You already own the parts | You already own the parts |
| Price | from 169.00 € To the product → |
99.00 € To the product → |
from 149.00 € To the product → |
from 83.00 € To the product → |
from 9.84 € To the product → |
9.90 € To the product → |
Prices include VAT and are pulled from the shop when this page is served. Shipping from 7 € within Germany, 15 € to the rest of the EU; UK, Switzerland and Norway are listed in the shop. Pay with Bitcoin (Lightning or on-chain) and 7 % comes off the total.
Take an assembled device. The SeedSigner+ is the most comfortable one: big display, D-pad, USB-C. The Rugged Pill is the same electronics in a shell that survives the backpack. The aluminium edition is for the desk — heavy, cool, no plastic. All three arrive tested; you add a microSD card with the software.
The DIY kit: Pi Zero with the header already soldered, display, camera with ribbon cable and the printed OpenPill case in your colour combination. About half an hour with a small screwdriver, no soldering iron. You end up with a device you have seen from the inside — for key custody, that is worth something.
Then you only need the case. We print the official OpenPill design from the SeedSigner repository in PLA, with the M2.5 threaded insert already fitted as the joystick head and a flexible TPU button in the box. One colour or two-tone — fits the Pi Zero, the 1.3″ Waveshare display and the Pi camera.
Hardware and software are fully open source. You don't have to believe a manufacturer — every component can be checked, by you or by the thousands of people who already have.
Your seed is never stored. Power off, everything is gone: after every restart the SeedSigner is as empty as on day one. There is nothing on the device for a thief to extract.
No Wi-Fi, no Bluetooth, no USB data channel. Transactions travel between wallet and device only as QR codes — you cannot get more distance from the internet.
Raspberry Pi, camera, display — standard parts available everywhere. No special chips, no supply chain you have to trust, no device that looks like a Bitcoin fortune.
You download and verify the software and write it to your own SD card. The chain of trust ends with you — not with us, and not with any other vendor.
You generate seeds yourself — with dice rolls or the camera as the source of randomness. No need to trust a random number generator you can't look into. That is exactly the failure mode that has hit closed devices.
Download the current SeedSigner release from github.com/SeedSigner, verify the signature, write the image to a microSD card and put it in the device. This is the one step that stays in your hands on purpose.
Roll dice, photograph entropy with the camera, or scan an existing SeedQR. Write the words down — on paper for now, in steel later. The SeedSigner forgets them the moment you switch it off.
Show the xpub as a QR code and scan it with Sparrow, Specter, BlueWallet or Nunchuk. The wallet watches your coins; the SeedSigner only ever signs.
Build the transaction in the wallet, show it as a QR, scan it with the SeedSigner, check the amounts and addresses on the device, sign, and scan the result back into the wallet. Done — no cable was involved.
21Drucker.Farm is a small 3D-print farm in Germany. We print the cases on Prusa and Bambu Lab machines, inspect every part, and assemble the devices by hand. Every assembled SeedSigner is powered up and tested before it ships — camera, display, joystick or D-pad.
What we deliberately do not do: we never ship a microSD card with software on it, and we never see your seed. A signing device with a pre-installed image would ask you to trust us. The SeedSigner project recommends against that, and so do we — flashing your own card takes ten minutes.
Orders ship within one to three working days with DHL. You can pay with Bitcoin over Lightning or on-chain through our own BTCPay Server (7 % off), or by card or PayPal. Questions before or after the purchase go to service@21drucker.farm and are answered within 24 hours. Returns follow the statutory 14-day right of withdrawal.
An open-source Bitcoin signing device built from a Raspberry Pi Zero, a small display and a camera. It holds your private key only while it is switched on, talks to your wallet exclusively through QR codes, and has no Wi-Fi, Bluetooth or USB data connection. You use it to sign transactions that a wallet on your computer or phone has prepared — the key never leaves the air gap.
Because a signing device with a pre-installed image would require you to trust the seller. You download the SeedSigner image from the official GitHub repository, check the signature and flash your own card. That way nobody — including us — has had a chance to tamper with the software that handles your key. It takes about ten minutes with a free tool like Balena Etcher or Raspberry Pi Imager.
The electronics are identical. With the assembled devices we mount everything, power the device up and test camera, display and controls before shipping. With the kit you do those thirty minutes yourself: plug the display onto the Pi header, connect the camera ribbon, screw the case together. No soldering. The kit is cheaper and you know exactly what is inside; the assembled device saves you the evening.
Any wallet that can exchange PSBTs via QR code: Sparrow, Specter Desktop, BlueWallet, Nunchuk, Electrum with the right plugin and several others. Single-sig and multisig both work. The SeedSigner is also a popular choice as one key in a multisig setup with other hardware.
For signing Bitcoin transactions, yes — and it takes a different approach. Closed devices ask you to trust their secure element, their random number generator and their firmware. The SeedSigner uses commodity parts, open code you can read, and entropy you supply yourself with dice. It stores nothing, so there is no device to steal secrets from. What it does not offer: a battery, a secure element, or support for coins other than Bitcoin. Many people run a SeedSigner alongside another device in a multisig — that way no single vendor has to be trusted.
That is exactly why the SeedSigner design matters: the device is stateless and you install the software yourself, so a seller cannot plant a key or a backdoored image. Hardware tampering is still possible in theory with any vendor — which is why the parts are standard components you can inspect, and why the DIY kit exists. If you want zero trust in us, buy the kit or just the case and source the Pi yourself.
Germany, every EU country, the United Kingdom, Switzerland and Norway. Orders leave within one to three working days with DHL. Shipping is 7 € within Germany and 15 € to the rest of the EU; UK, Switzerland and Norway are priced in the shop. Outside the EU, customs duties may apply on arrival.
Bitcoin over Lightning or on-chain through our own BTCPay Server, card via Stripe, or PayPal. Pay with Bitcoin and 7 % is taken off the total at checkout — you save the fees we would otherwise pay to the card networks, and we pass that on.
Write to service@21drucker.farm — we answer within 24 hours. Every assembled device is tested before shipping, but if something is defective on arrival we replace or repair it. Beyond that, the statutory 14-day right of withdrawal applies to all products. Since the cases are open-source designs, replacement parts can always be printed — by us or by you.
Fully assembled, as a kit or just the case — every SeedSigner we sell is in the shop with live prices and stock.
