Mollie the hamster is on Strava, and Runner's World noticed
6 August 2026Our MR physicist Thijs de Buck has built a speed and distance tracker for his hamster’s running wheel, with the data uploaded automatically to Mollie’s own Strava account. Runner’s World covered the project on 5 August, and the numbers are humbling: Mollie averages almost 10 kilometres a night.
The build is neat in its simplicity. A magnet on the wheel passes a hall sensor, which registers every rotation. An ESP32 microcontroller logs the data through the night, and in the morning a script turns it into a Strava-compatible .FIT file and uploads it through the Strava API. A small OLED display shows Mollie’s live speed, personal bests are tracked automatically, and more than a hundred possible run titles are on file — “The Fast and the Furriest” and “No Rest for the Whiskered” among them.
Automatic uploads turned out to require a paid account, which led to the only sensible conclusion available: “There was really only one reasonable solution: my hamster now has Strava Premium.”
Mollie, ten months old, turns out to be remarkably disciplined. He averages close to 10 kilometres per night, with a record of 10.8 kilometres in his first week of tracking, and over one seven-day stretch he started within the same ten-minute window on five separate nights. Signed up for Strava’s 400-minute August challenge, he completed it on day two.
That Thijs is a keen marathon runner himself, currently working around a minor injury, goes some way to explaining the level of instrumentation. “When I get back, I think it’ll be a nice challenge to try to match Mollie’s weekly running distance,” he said. “I don’t normally hit 70 km a week!”
The next milestone is Mollie’s twentieth run, at which point Strava starts issuing race predictions. “I can’t wait to see his estimated 5K and marathon times,” Thijs said, “and whether he’ll manage to improve those predictions over time! Although I’m a bit worried he’ll have a better marathon time than me.”
by Diederick Stoffers