Doug had a problem to solve: when he swims early in the morning, there’s not enough light to see the pool’s pace clock at the end of the lane. Like any good maker, he devised his own solution. He built a waterproof swim timer that uses an LED display to show your time. He also added a button to switch into a mode to time individual sets without disrupting the total time. The brain inside the clock is a ATmega328P with the Arduino bootloader and Doug says that he can get 100 hours of usage out of four AA batteries. Full code, schematics and build instructions are available for perusal on his site. Doug, from one swimmer/maker to another, I salute you! [via Adafruit]