Blockchain Rowers at ETHBerlin

Players earned xDAI by beating a timed rowing challenge, then spent their reward at a blockchain-connected vending machine.

Back in 2018 and 2019, blockchain was at peak hype. Everyone seemed to be searching for that breakthrough app ordinary people would want to use. The user experience was still awkward - they needed a wallet, cryptocurrency, and gas before they could do much. But that didn't stop us from exploring odd ideas and having fun as hackers. At NBT, one idea kept coming up: could we gamify certain experiences like turning physical activity into a reward paid through blockchain? We had already played with snowboarding and "coffee tokens," collected from a connected coffee machine- that story deserves a separate post someday. Then, the prestigious Ethereum hackathon ETHBerlin Zwei came around, and NBT wanted to showcase their blockchain prowess. This time we teamed up with a fitness group called Baerliner Berlin, and replaced the tiny coffee machine with a vending machine - big, bulky, and unmistakably a relic of the '90s. Standing between a few rowing machines, and the huge vending machine, and all the blockchain chatter, we discussed - Would people exercise more if they could literally create money with the effort? Not points. Not badges. Real tokens earned by rowing 100m in, say, 18 seconds, verified by the blockchain, and spendable at the very vending machine. The idea excited everyone. Hardware engineers wired rowing machines that had never been meant to communicate. Embedded engineers pulled out the race results. Software engineers built the cloud infrastructure on gETH nodes. Raspberry Pis and Python bridged the physical and digital worlds. A small AWS Lambda service created an xDAI reward link for each winner. Players could scan a QR code, claim the reward in a browser-based burner wallet, and send it to the vending machine. Another Raspberry Pi watched for the payment and spoke MDB with the machine, telling it to release the prize. No wallet setup. No cryptocurrency to buy. No gas to find before playing. ETHBerlin Zwei drew hundreds of hackers and several well-known names from the blockchain world, including Vitalik Buterin. Our setup was irresistible: three rowing machines, a vending machine, a bunch of colorful wires, and the promise of Ethereum for a DeFi future. Someone stepped up, pulled 100 meters against the clock, and beat the target of 18 seconds, all while we boisterously cheered them. Then they scanned the reward, walked to the vending machine, and spent it. When the prize dropped, what was just a fun idea suddenly felt exciting and tangible. Row. Earn. Spend. The loop was simple, almost silly, but it worked. People stopped to watch, then lined up to try. More than 150 of them took a turn. That old vending machine was no longer a relic. It had become the final link between effort and reward. For a few minutes at a time, blockchain stopped being hype and became something people could see, use, and laugh about.

NBT AG · 2019 · Hackathon team member