Hi All,

I've just register here and it seems it's a very good place to exchange the knowledges .
I have a project and I hope someone can help me . I am a member of a new born speed skate club and we are Looking for a stop watch timer for our time trial races . The club hasn't money at the moment to buy it and because my background is electronic , I've offered that I might be able to build that
I could build a good size digital display with LED and now just looking for an innovative and not expensive design .
Any help appreciated . I can discuss more details if anyone can help
Me on this matter .

Cheers ,
Bob

 

how would you make? using microcontroller?

if you can construct the hardware part then i can help you with its programming. i am good at programming stuff.

 

What are your timing needs. This can be done relatively simple. If you settle for seconds tenth of seconds and hundredth of seconds. Using ripple counters. A microcontroller solution will be more elegant and less parts of course. You will only need one chip

 

Here's a lesson that took me years to realize: building some electronic item has a vanishing small chance of being cheaper then buying it.

A display like this needs large numeric digits bright enough and with a proper color to be seen in daylight outdoors. As people will be looking at it you want it in a good looking case too, or all anyone will see is how bad the case looks. (A good looking case "disappears," an ugly one attracts attention)

If I haven't sacred you off yet (and good for you if I didn't) there have been a few threads about this here. The hard part is the display, timing itself can be done several hundred ways. I'd suggest for your sanity you find a kit for the digits so you get a PCB ready for some LEDs. That will keep them positioned correctly and save you time and money to make your own from scratch.


Case in point: I'm replacing a 30 minute mechanical timer with a "simple" electronic push button. Timer to be replaced was about $25, my replacement starts with a $1 controller and a $7 switch. Getting them into the box with all the other parts I'm into this thing for at least 50 bucks. I keep at it as the existing timer can (and has been) set too long and there is nothing available to meet my specific needs.

 

Thanks for all for reply . I've already build LED display and i just need to have a proper design to count Minutes , Seconds and seconds tenth of seconds and hundredth of seconds and display it on the seven segments . Then I can connect my own display to it as my display has a separate PS so i just need an input for the board . Building the display didn't cost me too much i spent around $150 to build a 100x40 Cm LED display .I am suer if i wanted to buy such a display it would cost me a fortune .

 

Show your circuit for your display so we can figure out how to interface to it.

 

Thanks for all for reply . I've already build LED display and i just need to have a proper design to count Minutes , Seconds and seconds tenth of seconds and hundredth of seconds and display it on the seven segments .

What is your budget for the timer device? Is a microcontroller solution out of the question.

 

I've already build LED display and i just need to have a proper design to count...

OK great, that is the hard part.

Show us what you have and we'll make way too many suggestions.

I am suer if i wanted to buy such a display it would cost me a fortune .

Me too!

 

Here's a lesson that took me years to realize: building some electronic item has a vanishing small chance of being cheaper then buying it.
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I agree with this totally, and I also regularly say why you are doing it is important. If you are wanting to do this to learn then I would be one of the first to say go for it the hard way.

The choice then becomes whether you want to do this with a µC or discrete logic. I have noticed a lot of beginners using microcontrollers are clueless when it comes to making things with flip flops and gates, so it becomes an issue of what you are trying to learn.

With electronics, there are many ways to skin a cat, but don't tell Bertus (another moderator) I said so.