Hamster on Strava: An MRI Physicist's ESP32-Powered Wheel Tracker
A physicist rigged his hamster's wheel with a hall sensor and ESP32, auto-uploading nightly runs to Strava. The hamster logs 6-mile nights, and the build is a neat lesson in DIY fitness tracking.
Thijs de Buck, an MRI physicist in Utrecht, got tired of guessing how far his hamster Mollie ran at night. So he built a tracker: a magnet on the wheel, a hall sensor to count rotations, and an ESP32 to log the data. Every morning, a script on his laptop converts the data into a .FIT file and uploads it to Strava via the API. Mollie now has his own Strava account, complete with splits, kudos, and a paid Premium subscription—because auto-uploading requires it.
The numbers are surprisingly athletic. Mollie recently logged 6.06 miles in 4 hours 37 minutes, and 5.55 miles the next night. He averages about 10 kilometers per night, with a record of 10.8 km. His schedule is oddly consistent: over a seven-day stretch, he started running within the same 10-minute window on five nights, between 9:54 and 10:04 p.m. He runs in short bursts at 4-5 km/h, then hops off for water.
The build wasn't without hiccups. An initial bike computer worked but went into standby after five minutes of inactivity, losing data if Mollie took a break. De Buck wanted full Strava integration, so he moved to the ESP32 setup. He added an OLED display for live speed, automated personal-best tracking, and over 100 run titles like “The Fast and the Furriest.”
Mollie's account gained over 1,200 kudos and 600 followers within a week. He also completed Strava's August 400-minute challenge on Day 2. De Buck, a marathon runner himself, jokes about matching Mollie's weekly 70 km. Next milestone: Mollie's 20th run, when Strava starts giving race predictions. De Buck worries Mollie might get a better marathon time than him.
There was really only one reasonable solution: my hamster now has Strava Premium.
Source: Runner's World