Swimming is a great way to exercise, both for the cardiovascular benefits and the improved muscle tone. However, while he’s a fan, [Peter Quinn] sometimes finds it hard to keep track of how far he’s gone when he gets in the zone. Obviously, the solution is an electronic lap counter, which [Peter] promptly set about creating.
The build is based around an ultrasonic distance sensor, which is triggered when it detects a swimmer approaching the end of the lane. It’s run by an Arduino Nano, which is also set up to announce the accumulated distance with a speech synth library. [Peter] notes there have been some stumbling blocks thus far, necessitating modifications along the way. Water ingress into the ultrasonic sensor has required the installation of a protective shroud, while battery operation has required a module to properly handle the lithium-polymer battery.
While we might hesitate to bring a takeaway container full of wires, circuit boards and an LED display to a public pool for fear of being deemed a bomber, the basic bones of the project are a great way to approach the problem. There’s plenty of scope to implement laptiming too, as we’ve seen in other sporting builds!
Once you have a track and a kart to race on it, what’s missing? A lap counter that can give your lap times in hardcopy, obviously! That’s what led [the_anykey] to create the Arduino-based Lap Timer to help him and his kids trim those precious seconds off their runs, complete with thermal printer for the results.
The hardware uses an infrared break-beam sensor module (a Velleman PEM10D) to detect when a kart passes by. This module is similar to a scaled-up IR reflective object sensor; it combines an IR emitter and receiver on one end, and is pointed at a reflector placed across the track, up to 10 meters away. When a kart breaks the beam, the module reports the event to the rest of the hardware. Only needing electronics on one side allows the unit to be self-contained.
An obvious shortcoming of this system is the inability to differentiate between multiple karts, but for timing a single driver’s performance it does the trick. What’s great about this project is it showcases how accessible hardware is today; a device like this is possible to put together with what are essentially off-the-shelf components available to any hobbyist, using an Arduino as the glue to hold it together. We’d only comment that a red-tinted piece of plastic as an overlay for the red display (and a grey-tinted one for the green) would make the LED displays much easier to read. Still, this is a very clean and well-documented build. See it in action in the video embedded below.
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