Is it possible to make a timer with garage door photo eyes and a digital timer?
It has to start timing when the beam is "broke" and stop when it is "broken" again.
I, by no means, am a pro so if this is possible, please explain in terms that a child could understand

The timer will be a single start/stop button. And I know that I would have to somehow add a power source.

Thanks a bunch !!

 

Hello,

I found this thread moderated (invisible to others) in the "completed projects" forum.
As the title says this forum is only for completed projects.
I moved it over here and made it visible.

Bertus

 

The OP may be interested in this very similar thread.

 

Is it possible to make a timer with garage door photo eyes and a digital timer?

The short answer is yes. But the devil is in the details. You need to first determine what power the photo eye needs and what sort of output it produces. Once you have that "on or off" output figured out, you'll be on the same page as the other thread I just linked.

 

So it is definitely a count up timer with a large duration possible?

 

I believe garage door sensors use some oddball system of signal being on the same wire as power. Like a DC voltage to power the sensor and then an AC signal on top of it to signal that the beam has been broken. I just remember reading that somewhere, not sure if it applies to all garage door sensors. If the sensor had a digital output separate from the power it would be much easier.

 

http://www.electronicspoint.com/re-garage-door-safety-sensors-t241501.html

 

Thanks everyone for the helpful info and the links.
@Bill, yes it needs to be a count up timer. I barrel race and need to train and practice new horses. The ones you buy are 800+ bucks. I'd rather figure out a way to do this with <50.00. And it needs to be instant, no delay. Has to be timed to the .0000 second

 

How big do you want the digits?

I'm thinking of starting a cookbook of such circuits. One of our brighter members (an architect by trade) has taught himself electronics (mostly digital) and is building a soccer scoreboard, which has many elements of what you are wanting to do.

To me the circuits are fairly easy, to a beginner not so much. If you want large digits there are both off the shelf solutions and DIY.

Count down timer for my soccer club

I suspect you will get lots of help, the question is specifics, such as display sizes. Large display cost more money.

4 digits after seconds is doable, not realistic, but very doable. You are measuring to 100 microseconds with that digit count.

So the display in total is Minutes:Secondsartial seconds

00:00:0000

Do you have someone that is handy with both electronics and carpentry (or metal working)? This only applys with large digits, with small ones the other suggestions (mostly modifying a pre-existing timer) apply very well.

The project is basically easy, the devil is in the details.

 

How will you attack this problem. Will you be using some sort of microcontroller or discrete logic gates/ICs. It can be done both ways. It will be an ideal task for a micro. Then using discrete logic. Such a project may grow big then you are a beginner. Do you have any budget?

 

Under $50. A large display could eat that to nothing, though there are ways if you are handy.