Nikodem Bartnik enjoys making things, as presumably most people reading this do as well. He also enjoys running, which is something that I’d guess fewer of us have in common. To help with both pursuits, he’s built a DIY sprint race timing system using an Arduino Nano for control, along with ultrasonic sensing to tell when someone has passed the unit. A small speaker signals the start of the race from its position at the finish line.
The 3D-printed enclosure for the device includes a tripod mount, which allows the sensor to be positioned to see a person’s body. It can then get a better reading than when sensing a runner’s legs or feet on the ground. Interface buttons let him set the race distance between 50m and a full kilometer, and user feedback is via a small e-Paper display. While this might seem like overkill, Bartnik notes that he used it because — well because he can — and per the fact that its easy to read in daylight as well as power efficient.
You can see him trying out the timer around the 6:00 mark in the video below. While his current race time isn’t impressive enough to show, he’s planning to practice and hopefully get better as perhaps a subject for another video. Print files are found here and code is available on GitHub if you’d like to create your own.