How to make a sports timer?

Question

Do it yourself

Need a timer for sports competitions.
Т.З.:
1. The presence of a dial, the countdown to the nearest tenth of a second
2. Start from opening the first button, stop when the second one is closed.
Those. it turns out that at the start a person stands on a button-key-pedal, he just removed his foot - the time has gone.
When you reach the finish line, you need to hit the finish button to fix the result.
If anyone has links to something similar, please share.
I met an article on Habré about a clock on a microcontroller, but I haven’t found it yet.

Answer 1

here is an article from habr.

Answer 2

I did without controllers at all - the hardware part looks like an emitter on two IR lights with a master oscillator at 38 MHz, the receiving part is an IR receiver that works only on a 38 MHz carrier and an output relay, completely all the electronics fit into a 3x3x4 cm case or less (I have power relay), the width of the barrier is up to 50m, and then the data goes to the COM port or to usb. Processing of results, distribution of places, automatic calculation of fines, I conduct DB of athletes in a handwritten program. Binding to the processor frequency is quite accurate ... The ability to output to a huge scoreboard, print a protocol, online display of results. Nothing complicated, but it works perfectly and most importantly - convenient!
IMHO, buttons are nonsense, because if a runner, for example, got carried away running at the finish line and didn’t hit the button, then he is unlikely to run again, except perhaps to “explain” to the unfortunate designer that they don’t build like that ...
I can give a diagram if I find ...

Answer 3

Here is a link to an article about creating a clock on the ATMEGA16 microcontroller.

Answer 4

In general, I assembled a stopwatch based on the training Altera, well, it turns out to be very cumbersome. On the eZ430-Chronos, it will turn out much prettier.

Answer 5

I would recommend using AVR microcontrollers (or Arduino), in which case the timer circuit is easily searched for by the phrase "avr timer".