Building an LED 60 second clock with an ardino for swimming.

Hello I am very new here.
What I want to do is build an led clock that counts up to 59 and resets to zero. It is used in swimming practice. I have made some simple led
digital counters but they have to be manually advanced and they go till 99 before resetting.
I use larger segment that draw about 100ma each. Any help is greatly appreciated.

Have you looked at the Stopwatch stuff in the playground?
Using two ULN2803's you can drive two seven segment displays with high voltage high current segments no problem (like 4-5 LEDs in series to make each digit).
Put the 2 parts on a protoshield with connectors to the segments, couple of buttons for start/stop, reset.
Easy project.

Thank you for the reply. Like I said i am very new. In fact I am waiting for my first ardino to arrive.
I have made simple counters that we use at swim meets but I want them to be dual function. I also run my stuff at 12v. Usually from batteries or transformers. I will look at your references and hopefully get them. Your talking French to me now but I learn fast.
Actually if I can do the start stop reset thing is exactly what I have been trying to do since I made the signs 3 years ago. I only found out about ardino's 1 month ago.
Would it also be possible to use it as dual function. Stopwatch and during a meet as a deli counter or easier to switch inputs from LED's

"Would it also be possible to use it as dual function. " Yes.

"deli counter" Yes.

"or easier to switch inputs from LED's" Not sure what this means, but likely Yes.

You have 20 I/O pins to play with.
If you use to drive the ULN2003 to sink current for the LEDs:
+12V - LED - LED - LED - LED - resistor - ULN2003 Collector, emitter to gnd, "gate" driven by Arduino I/O pin per segment
that is 14 pins used.
Keep D0, D1, free for serial coms.
that is 16 pins used.
Leaves 4 pins free for buttons to do what you want - 1 pin to select program to run, 3 pins as inputs for those programs. Even use the 2 serial pins as button inputs after the sketch starts if you are not doing any serial stuff.

Mount the ULN parts on a protoshield with leads off to your buttons.
Or go wireless even - use a couple pins for RF receiver, make an RF transmitter to send it start/stop/whatever commands.

Thanks those chip you said to order have solved a long time problem I have had with my current LED signs. If I read the information correctly.
Not sure what i will need to input but i have 10 V and at least 40ma.
Do you have any ardino books you would recommend ?
Or at least a data page. Also there seem to be a few different ardino's out there and I don't know which one is best for my led stopwatch. I hate to be a pest but I want to learn all i can. This problem has been bothering my for 3 years and I seem close now.

Also there seem to be a few different ardino's out there and I don't know which one is best for my led stopwatch. I hate to be a pest but I want to learn all i can.

CrossRoads has been giving you info on the Arduino Uno which has 20 input/output pins. So does the older Arduino 328.

Do you have any ardino books you would recommend ?

Since you're working with leds I would recommend the same tutorial I did, the 5 step ladyada tutorials, starting here: Arduino Tutorial - Getting ready

There are other books with more advanced beginner projects, like the free earthshine electronics pdf book: but if you just do web searches project by project you can learn a lot that way.

I have never built an uno into anything, preferering to use the smaller (and less costly) promini, or just assembling the few components needed (xtals, two 22 pf caps, 10K resistor, 100nF caps, and I usuallly have a 5V wallwart so no regulator).

I don't have a book to recommend. The earthshine book looks good.

My power was out for a couple days, let me know if you need other help.

Well thanks for the information. I have been busy with construction of a current project. Now it seems I really need to complete the stopwatch project coach is very interested.
I have found a rtc that looks very interesting.
What I have now is 2 sets of 2 digits each that I presently use as an event indicator for the swim meet. I use a commercially available 4 channel remote. This system runs off 12V.
Can I run 4 digits from a promini and program it to alternate between 2, 2 digit counters and a 60 minute timer. I have the chips you recommended before but it may be a while before I get there.
I will order a promini, and see what i can learn. Already have lot in the project I can see the light.

I couldn't find the promini, but I located this one on ebay that takes 12V in. My signs always run on 12V.
Probably more than I need but I know what would happen the other way I would forget to set the power supply and destroy it.