Raspberry Pi Bitcoin wallet

A couple of weeks back, Stuart Kerr from mailed me to let me know they were thinking about using a Pi to mod a coin-operated pool table to take instead; he wanted to know about using our trademark. I mailed him a link to the trademarks rules, made a note about the pool table idea, and then got back to what I was doing – lots of people mail us to tell us they’re starting projects, but not everybody actually finishes the project they’re mailing us about.

Pool tables are another of those things with acres of unused space inside, ideal for filling up with electronics if you’re that way inclined, so finding a slot for a Raspberry Pi wasn’t difficult. The table has a regular coin slot, which works as you’d expect – but next to that the Liberty Games team have installed an LCD screen displaying a price in bitcoins, with a QR code next to it. To play, you scan the code on your phone, and send the amount displayed to the operator’s bitcoin wallet. The table’s ball release mechanism then triggers.

Stuart says:

There were a number of challenges: make it easy to use, fast, secure, idiot proof (for those Bitcoin aficionados who’ve had one too many ales before they play) but most of all – try to make it easier to pay with Bitcoin than cash (although paying with cash should still be an option).

Immediately we thought about the Raspberry Pi (a cool $25 credit card sized computer) – we’ve seen Pis do all kinds of fun and interesting things (even go to space), so we were sure the Pi would be the key. Luckily the Pi is extremely flexible and has a very active community of developers and add-ons.

After a fair bit of coding we managed to get the Pi talking to a server which itself was talking to the peer-to-peer Bitcoin network, with the Pi checking to see when an incoming payment of the correct value came in. We also designed a web-based admin panel (run by a web server on the Pi), to allow operators to set the price per play and transfer Bitcoin to another wallet.

As the value of Bitcoin is variable (to say the least), we also incorporated an LCD display which calculated the current price in Bitcoin of the selected price per pay.

So all we needed to do was install the Raspberry Pi in the pool table (we chose to use a Supreme Winner table due to their popularity in pubs and bars). The Pi can run either from a battery pack or from a mains adapter (the same as the electronic coin mechanism), so there’s no extra hassle.