Using a Pebble Watch to Receive Bitcoin Payments David MoonMay 22, 2013 A fundraising record-setter of the Kickstarter crowdfunding site, smart watch maker Pebble began shipping thousands of units to backers and pre-orders earlier in 2013 to much praise and even appears to have inspired Apple and other companies to rush their own take on the smart watch product to market. With so much undiscovered potential for this and other wearable devices, let’s see how we can use this in the cryptocurrency space! This article will show you how to set up the proper machine-readable QR code of your own public-facing wallet key on a Pebble and as an added bonus, add a clock in there as well! What you will need for this method: A Pebble watch An Internet-connected device paired with the watch via Bluetooth (i.e., a phone or tablet) A laptop or desktop computer also connected to the Internet with some sort of graphics program. You will only need simple commands like select, crop, and resize. A Bitcoin wallet, ideally with a QR code. If you just have the text string, go here for a couple good conversion methods to use. If you do not have a wallet at all, you may want to explore this site that discusses your options or if you just want a quickie wallet to play with for right now, go here. 1) For this guide, I set up a Blockchain account and put a few coins in it which, when I finally manage to get the Blockchain iOS app to work on my iPhone, I hope to be able to use to make and document purchases made “in the wild.” However one good thing about Blockchain is that right off the bat, it gives you the Bitcoin QR code and corresponding address that we are going to use. The Spelunkin BlockChain Account: Those with OCD should feel free to make that an even 2.5, a 3.0, or even a tidy 10. 🙂 2) Grab that QR code with whatever screengrab program you prefer and save it as a typical graphics file – png or jpg will do nicely. Make sure you get all of the code plus a few white pixels to serve as a border. This leaves us with a file that looks like this: Selected screengrab of the Spelunkin QR code from Blockchain.info 3) The Pebble’s screen is made up of 144×168 pixels. If the QR code you have is less than 144×144, you’re in good shape. If your code is larger than that, you’ll have to try to resize it to maybe 138×138 so you have a nice border of 3 white pixels all around as that seems to offer best results. If your total image – the QR code plus border – is smaller like the one above that is 133×132, then you should be ok because we are going to use this image with a white background anyway. However when you see what’s coming, you may want to revisit the background color, canvas size, etc. To keep it simple for now, we’re just going to use this graphic with an expanded canvas to make it is nice and tidy 144×144 as seen below. The same graphic but with an explicit white border around it making it 144×144. 4) Next up, let’s make a Pebble App! Go over to the online Watchface Generator here: An online application that lets you make simple watchface designs. 5) Select the Background tab and select “white” as the background color. This will fill any area not covered by your QR graphic with white pixels. Then pick Choose File to upload your QR code to the site. Watchface Generator – Background QR Code Uploaded 6) You probably notice that your QR code looks okaaay but there’s something garbly on it near the top. Those are a set of built-in Time and Date displays, in white, stomping over your graphic and we’ll fix those in a minute. Let’s just focus on the QR code. The sliders here let you fiddle (or fit) the width and height of the graphic as well as the position (X and Y) of the same. If you leave the code where it is by default, there’s a chunk of whitespace at the bottom we can use to add some other info, like a clock. So click the Time tab. Watchface Generator – Time Tab 7) Here you can play around with that clock I mentioned earlier. If you don’t want it at all, you can just use the Offset X and/or Offset Y sliders to move the clock offscreen and skip the rest of this step entirely. If you do want to use a clock, I recommend first switching the Font Color to black. Then you can use the Offset X and Offset Y sliders to maneuver the clock to the white strip at the bottom of the QR code. You can use the Alignment options to fast-forward your clock to the perfect horizontal position that you want and then adjust the Offset Y slider to place it in the proper vertical placement. You can also change the font type and size while you’re at it. You can also continue to experiment with the display using the Date and Text options, but let’s move on to getting this processed and on your device. When you’re completely done changing all aspects of your watchface – and you can go back to previous tabs to experiment around with different looks – click the Generate tab. Watchface Generator – Create Watchface (Also leaving the donation text in because, well, this is a pretty cool tool.) 8) Now name your app and select Create Watchface. Watchface Generator – Ready for Download 9) So now is the YMMV part. Basically you need to get the file behind that URL – in this case “spelunking_wallet.pbw” to your phone or tablet or whatever device you use to send watchfaces to your Pebble. You could use a QR reader to scan that code and have it launch the URL in a browser, you could copy that URL to your phone’s browser and open it that way. Alternatively, you could download the file to your desk/laptop and send it to your phone via any one of several tools, but the key part is, you need to get that URL (or really, the file behind it) to your phone so you can open it in the Pebble app. Using the iOS application QR Reader , I could capture and translate the code well but the in-app browser does not deal with the file so I just Share-Copied it and pasted that into Safari to get the following results: Our Watchface URL Opened on iPhone 10) Now just select Open in “Pebble” and the Pebble application will open and you will get a brief warning about apps which will go away when you hit Continue. Then the app is loaded to your Pebble! (Note: sometimes this does not happen on the first try. Just go to the home screen, kill the app, go back to your browser and try again.) Watchface Loaded Into Pebble 11) Done! Check out your watch – scroll through the existing faces and you should see yours pop up! Watchface Showing QR Code and Clock 12) Verify the code by pointing a QR-reading app at your watch and make sure the text that comes up is your public Bitcoin wallet key. Watchface – Result! Credits: DerekC who created the QR Code Contact Information Pebble Watchface which got me thinking. Jason S. of NMC design who created the My Pebble Faces website, which is a great source of general inspiration as a lot of people are contributing their Pebble ideas here. If you’d like to support them, they have a donation link at the bottom of the site. Paul R. who runs the Watchface Generator website which makes it possible for anyone to create and download their own watchface. They also have a donations button set up but it too is not Bitcoin compatible at press time.