Hi Everyone!.

I'm require some opinions on my electronic project.
I did build a mini-stove for my research project.
The stove has 4 red light on its burner-ring.

So, when I press the button, one of the red will be switch on.
At the same time, the stopwatch will be start counting.
The end-user has to choose which rotary switch (located at the front panel of the stove) to switch off the light. There will be 4 rotary switch.
Once user choose the right rotary switch to off the light, the stopwatch will automatically stop counting too.

In this project, I didn't build the stopwatch using any pic or 7-segment LED. I use a digital stopwatch, open it and soldering the stop, mode and reset. At this moment I try to use relay.

Relay will triggered the light and stop watch at the same time. (12v relay)
However, the light is working with relay but not with the stop watch.
Any idea any one? or got better suggestion?.

I try my best not to use PIC or anything program..as I'm weak in programming.

 

You need another pulse to stop the stopwatch. You can use a 555 one-shot to pulse the stopwatches 'stop' button when the trailing edge is detected.

 

Hi rm,

From my understanding, what you said was that between the relay and stopwatch, there is 555? Or is don't need a relay?

The problem right now is that when I push the button, the light is on and I can hear the relay is triggered, but it just don't triggered the stopwatc at the same tim.