Set up a SeedSigner with Sparrow

Pick how you get your device

A SeedSigner is a small Raspberry Pi computer with a screen and a camera. It holds your keys only while it is switched on. Pick one of three paths.

Wi-Fi? The “W” boards have Wi-Fi and Bluetooth chips. The SeedSigner software ships without Wi-Fi or Bluetooth support, so they stay unused. Want no radio chip at all? Pick a Pi Zero v1.3 and have pins fitted.

Get the parts

• Raspberry Pi Zero boardZero v1.3, Zero W / WH, or Zero 2 W / WH. All work.
• 1.3-inch LCD HAT, 240×240 pixelsA “HAT” is an add-on board that presses onto the Pi’s pins. The SeedSigner project lists the Waveshare 1.3" model. Check the pixel count before you buy.
• Pi Zero camera with an OV5647 sensorOV5647 is the camera chip. It must come with the short, narrow “Zero” ribbon cable.
• microSD cardAny size works. The software needs less than 64 MB.
• Micro-USB cable and powerAny 5 V phone charger or power bank.
• A case (optional)Free 3D-printable designs are in the SeedSigner project.

Bought a ready-made unit? Skip to step 4.

Put it together

1. Unplug everything. Hold the boards by their edges.
2. Find the thin camera connector on the Pi’s short edge. Gently pull its dark latch out about 1 mm.
3. Slide in the camera ribbon, metal contacts facing the board. Push the latch back in.
4. Line the screen up over the Pi so it covers the board. Press it straight down onto the pins until it sits flat.
5. Don’t power it on yet.

No picture later? Most problems are a loose ribbon or a screen not pressed all the way down.

Install Sparrow on your computer

Sparrow Wallet is free software. It shows your balance and prepares payments. It never sees your 24 words. Install it first: it will also check the SeedSigner download for you.

1. Go to sparrowwallet.com/download. Download the file for your computer.
2. Also download the two small files below it: the manifest and the manifest signature (.asc).
3. Check the files (see below), then install and open Sparrow.
4. When Sparrow asks about a server, choose Public Server for now.

Server? Sparrow needs a computer that knows the whole bitcoin history. A public server can see which addresses you look up. Later you can run your own node.

# import the Sparrow developer key
curl https://keybase.io/craigraw/pgp_keys.asc | gpg --import
# must say: Good signature from "Craig Raw"
gpg --verify sparrow-2.5.5-manifest.txt.asc sparrow-2.5.5-manifest.txt
# macOS / Linux: must end in ": OK"
shasum --check sparrow-2.5.5-manifest.txt --ignore-missing

Don’t skip the check. A fake wallet app can steal your bitcoin. Once Sparrow is installed, it checks future downloads for you.

Download the SeedSigner software

1. Go to the SeedSigner releases page. Open the newest release (0.8.7 when this was written).
2. Download the file for your board: …pi0.img for Pi Zero v1.3, W and WH. …pi02w.img for Pi Zero 2 W and 2 WH.
3. Download two more files into the same folder: seedsigner.0.8.7.sha256.txt and seedsigner.0.8.7.sha256.txt.sig.

What are those? The .txt file lists a fingerprint of each release file. The .sig file proves the SeedSigner team signed that list.

Check the download with Sparrow

1. In Sparrow, open Tools → Verify Download.
2. For the signature, choose the .sig file. Sparrow usually finds the other two. If not, browse to the .txt and .img files.
3. Sparrow must show the release as signed by SeedSigner, with green ticks.
4. If Sparrow asks for a public key, download SeedSigner’s public key and select it.

Red or failed? Stop. Delete the files and download them again. Never write a file that fails the check.

# import the SeedSigner project key
gpg --fetch-keys https://keybase.io/seedsigner/pgp_keys.asc
# must say "Good signature"
gpg --verify seedsigner.0.8.7.sha256.txt.sig
# must end in ": OK"
shasum -a 256 --ignore-missing --check seedsigner.0.8.7.sha256.txt

Write the microSD card

1. Put the card in your card reader.
2. Open Raspberry Pi Imager or balenaEtcher (both free).
3. Choose the checked .img file. In Raspberry Pi Imager it is under Use custom.
4. Choose your card and write. If Imager offers to customise settings, say no.
5. Wait until it finishes and verifies. Then eject the card.

Switch it on

1. Slide the card into the Pi’s card slot.
2. Plug power into the micro-USB port marked PWR IN.
3. Wait up to a minute. You will see the main menu: Scan, Seeds, Tools, Settings.
4. Move with the joystick. Press the joystick to select. The three small buttons are shortcuts.

Stateless SeedSigner forgets everything when the power goes off. That is on purpose: no keys are stored on it.

Make your seed with dice

Your seed is a list of 24 words. It is the master key to your bitcoin. Anyone who has the words can take the coins.

1. Go somewhere private. No phones, cameras or smart speakers nearby.
2. On the SeedSigner: Tools → New seed (dice icon) → 24 words (99 rolls).
3. Roll a real die 99 times and enter each result. Don’t make numbers up. People are bad at random.

Want to pick the words yourself with dice and let SeedSigner add only the last word? See the dice seed guide.

Write down and check your words

1. SeedSigner shows the words a few at a time. Write each one on paper, numbered 1 to 24, in clear block letters.
2. Choose Verify and answer the short quiz. It checks you copied them right.
3. Next you see the fingerprint: 8 characters that name this seed. Write it next to your words.
4. Skip the passphrase option for now and choose Done.

Never photograph your seed. Never type it into a phone, computer or website. Never.

Send your public key to Sparrow

1. Keep the SeedSigner on.
2. Seeds → your fingerprint → Export xpub → Single Sig → Native Segwit. If asked for a QR format, keep the first one.
3. Read the notice, then an animated QR code appears. Leave it on screen.

xpub Your public key. It lets Sparrow show your balance and make new addresses. It cannot spend. Keep it private anyway: it shows all your addresses.

Add the wallet to Sparrow

1. File → New Wallet. Give it a name.
2. Click Airgapped Hardware Wallet. Next to SeedSigner, click Scan….
3. Hold the SeedSigner 15–20 cm from your webcam. If it struggles, move the joystick up or down to change the QR brightness.
4. Click Apply. Set a password. It protects the wallet file on this computer, not your bitcoin.
5. Check the master fingerprint in Sparrow matches the one you wrote down.

Test your backup now

Do this before any bitcoin goes in.

1. Unplug the SeedSigner. Its memory is wiped.
2. Plug it back in: Seeds → Enter 24-word seed. Type the words from your paper.
3. The fingerprint must match Sparrow’s. Then your backup works.

No match? A word is wrong or out of order. Fix it now, while the wallet is empty.

Check a receive address on the device

1. In Sparrow, open the Receive tab. It shows an address and a QR code.
2. On the SeedSigner, choose Scan and scan that QR. Pick your seed.
3. It confirms the address belongs to your seed.

Do this before every bigger payment in. It proves your computer didn’t swap the address.

Receive a small amount

1. Send a small test amount to the address you just checked.
2. It appears in Sparrow under Transactions.
3. Wait for one confirmation: the payment is written into a block. Usually 10–60 minutes.

Small amounts first. Move more only after your test send works.

Create a test send to yourself

1. In Sparrow, open Receive and copy your next address.
2. Open Send. Paste that address, enter a small amount and pick a fee.
3. Create Transaction → Finalize Transaction for Signing → Show QR.

Unsigned transaction A payment draft. It does nothing until your SeedSigner signs it.

Sign on the SeedSigner and send

1. If the SeedSigner was off, enter your 24 words again.
2. Choose Scan and scan Sparrow’s QR code. Pick your seed.
3. Read the amount, fee and address on the SeedSigner screen. If all is right, choose Approve transaction.
4. A signed QR code appears. In Sparrow click Scan QR and hold the device to the webcam.
5. Click Broadcast Transaction.

Trust the small screen. Malware can change what your computer shows. The SeedSigner screen can’t be changed that way.

You’re set

1. Keep your words and your SeedSigner in different places.
2. Each use: power on, enter words, scan, check, sign, power off.
3. Later, copy your words onto steel. See steel backups.
4. Next steps: run your own node. A multisig guide is coming.