You've set up your COLDCARD™ and you're ready to try it out. What's next?
Let's get you started with some easy transactions using your COLDCARD and Sparrow Wallet.
If you've never installed GPG software or a desktop wallet before, don't be intimidated. Each of the apps listed are easy to install and have good documentation to step you through the process if you get stuck. Take your time and you'll learn faster than you might expect.
NOTE: If you're going to use a wallet that has a passphrase, make sure to apply the passphrase immediately after entering your PIN. If you don't apply your passphrase, you'll export the values for your default wallet and won't be using your intended wallet.
The JSON file you'll save contains XPUB information Sparrow Wallet needs to process your transactions.
Advanced > MicroSD Card > Export Wallet > Generic JSON
. Read
the message shown and press OK(✔) to continue.0
when prompted for an account number.coldcard-export.json
. Press OK(✔) when it is finished..txt
file.asc
fileConnecting to a Private Electrum Server
screen appears, select
Later or Offline Mode
.coldcard-export.json
to the Sparrow window.Sparrow Wallet will search for transactions associated with your wallet (displayed at the bottom of the window) as soon as it connects to a server. It's ready to use!
You'll notice Sparrow Wallet displays a lot of information. It's okay if you don't understand everything yet, there's a lot to learn.
To receive Bitcoin, you need give the sender a valid receive address generated by your wallet.
Software wallets, like Sparrow, automatically select the first unused receive address when you need to receive Bitcoin. Since it is tracking your wallet transactions, it knows which addresses have already been used. Reusing addresses is possible, but strongly discouraged for security reasons.
When you're ready to receive Bitcoin (who isn't?) log in to Sparrow Wallet and
click the Receive
button on the left side of the window. A receive address
will be shown along with a QR code. Enter a Label
for the transaction if you
want, but it is not required. Give the sender the string of text in the Address
field or give them QR code and they can send you Bitcoin. Easy.
Sending is a little more complicated than receiving, but still very straightforward so long as you're careful. These instructions take you through signing a transaction without connecting your COLDCARD to your computer (airgapped) which minimizes risk.
Send
button on the left side of the
window.Pay to:
field. You can
paste the text string or take a picture of the QR code with your webcam.Label
field must not be empty, so enter whatever information is
appropriate for the transaction, even if it is only one character.Create
Transaction
.Finalize Transaction for Signing
.Save Transaction
and navigate to your microSD card to save the
Partially Signed Bitcoin Transaction (PSBT).Ready to Sign
from the main menu.Reading . . .
and Validating . . .
before
displaying transaction details. Take every opportunity to check and double
check transaction information. Make sure the address you are sending funds
to is absolutely correct.-signed.psbt
, the other -final.txn
.Load Transaction
.Open
.Signatures
bar turns blue, confirming the transaction is signed. Click
the Broadcast Transaction
button to finalize the transaction by
broadcasting it to the Bitcoin network.The Blockchain Status will remain Unconfirmed until Bitcoin miners verify the transaction.
You can connect your COLDCARD to your computer and sign transactions directly, but it is not recommended for high-value wallet balances or large transactions.
Best practice is to keep larger balances assigned to a COLDCARD that is completely offline and have a separate wallet for smaller amounts available for spending.
Send
button on the left side of the
window.Pay to:
field. You can
paste the text string or take a picture of the QR code with your webcam.Label
field must not be empty, so enter whatever information is
appropriate for the transaction, even if it is only one character.Create
Transaction
.Finalize Transaction for Signing
.Sign
button with the USB symbol in the
lower-right corner.Sign
.Signatures
bar turns blue, confirming the
transaction is signed. Click the Broadcast Transaction
button to finalize
the transaction by broadcasting it to the Bitcoin network.The Blockchain Status will remain Unconfirmed until Bitcoin miners verify the transaction.
Congrats! Go stack some sats!
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