Bitcoin has been making headlines for many years now, and a large percentage of the articles below those headlines focus on the inherent intangibility of the cryptocurrency. How can something that doesn’t exist in any physical form have value? If you have Bitcoin, it’s only as valuable as what you can exchange it for. To prove that those exchanges are practical, David Knezić has created a candy dispenser that accepts Bitcoin.
Aside from the obvious fact that everyone loves candy, Knezić’s build is important because it demonstrates the viability of very small Bitcoin transactions. The dispenser itself is built around an Arduino Micro, which is controlled by a computer through a USB serial connection. The computer monitors Bitcoin transactions through blockchain.info, which is a public website where you can see the entire Bitcoin blockchain — the log of all Bitcoin transfers. When the computer sees Bitcoin being transferred to the dispenser’s account, it tells the Arduino to dispense an appropriate amount of candy.
It works, but has two major shortcomings: time and fees. The Bitcoin blockchain isn’t updated instantly, and so it can take several minutes for the transaction to be verified and posted. Each transaction also carries a relatively high fee, which means that you may be paying more in fees then for the candy itself. Both of those might been solved soon by the Bitcoin Lightning Network, which is designed specifically for small transactions that need to be verified quickly. It’s yet to be seen if the Lightning Network will be successful, but the potential for small cryptocurrency transactions — like buying candy — is obvious.