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, itís still dark out then, so he canít 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.
The timer is visible through the water when it is underwater, but that's not how I normally use it.
You can modify the code for count-down timing. I've thought of doing that so that when I want to time a set of laps I can have say a 3 second count-down from when I flip the switch to when I need to launch.
The code in the Arduino is only using about 10% of the program memory so there is lots of space for modifications.
Using red plastic over the display to improve daylight visibility would be an interesting experiment. The visibility in direct sunlight is not good, but then I use the large unlighted timers around the pool when there is daylight. Improving the daylight visibility would make the timer more versatile.
Good point, Doug. Yet, since you created the gadget specifically for night use, you probably didn't see the need to make a display that would work during sunlight. I would guess you had that solved through a wristwatch or other daylight device.
Really cool device, but if you ever market it to the public, make sure you enclose a disclaimer that you are not encouraging "Night swimming alone." I can see hoards of hungry attorneys waiting to sue your socks off because some yahoo drowned while night swimming by him/herself as your device allowed them to do.
Don't laugh. You would not believe some of the ridiculous law suits processed in our neighboring state of Illinois.
The microcontroller used is an Atmel atmega328P, better known as the microcontroller used in the Arduino. The swim timer is compatible with the Arduino integrated development environment so it makes it easy to modify the code. As I recall the timer code uses around 10% of the 32kbytes of program memory.
Ah, Tool Maker, you're right. I have a brother who lives in Illinois and he's continually pointing out these ridiculous suits. He says he's reached the point where he doesn't say nice things when a friend talks about a son or daugher who is going to law school.
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