Gadget Freak Case #210: Digital Timer for Night Swimmers 16013

Doug Conner trains with his triathlete group in an outdoor pool. His start time is 6:00 a.m., and during half of the year, it’s still dark out then, so he can’t see the analog clock. To fix this, Doug created a waterproof timer he can place at the edge of the pool.

The nighttime swim timer uses a battery-powered microcontroller with a crystal time base that drives a four-digit, seven-segment LED. The microcontroller takes care of all aspects of timing and display, including driving the LEDs. The half-inch digits make the display easy to read from 10 feet away.

Doug Conner created a digital timer so he could check his pace on his 100-meter laps in the dark.

The timer is encased in a transparent, waterproof polycarbonate tube
and can go to the bottom of the pool without leaking.

Build Instructions