Morning Albert,

With the resistor connected it now reads 15.6v on the right terminals which then drops to 11.2v when the left button is pressed.

The press also still operates normally

In that case an opto-coupler will do the job nicely. Connect the 12k resistor to whichever of the button terminals is positive. Make R1 in your circuit 220k.

 

Hi Albert thanks for this!!!

Just to confirm that the 12k and the 220k will basically be connected in series?

 

Hi Albert thanks for this!!!

Just to confirm that the 12k and the 220k will basically be connected in series?

No. Sorry we now have two R1s.
In your circuit there is an R1 connected to the original SW2 - that resistor should be 220k.

EDIT: And remove the 12k test resistor from the button terminals and connect the opto-coupler via a 12k resistor to the button terminals.

 

Ahh i get what you mean

So my PCB will look like this:

 

sorry should say R1 12k

 

Yep!

 

ill let you know how it goes, 4N25 should be with me by the end of the week

 

Hi Albert, i made the opto-coupler, fitted it and wired it up and now it doesn't work at all! the counter just stays at 000 and does nothing when the triggers are pressed?

 

Hi Albert, i made the opto-coupler, fitted it and wired it up and now it doesn't work at all! the counter just stays at 000 and does nothing when the triggers are pressed?

OK.
Make sure that pin 2 of the coupler is connected to the negative of the two switch terminals.
Make sure that pin 4 of the coupler is connected to the 0V of your circuit.

 

pin 4 is connected as the PCB and not to 0v, i will run a wire and see if it makes any difference.

 

OK.
Make sure that pin 2 of the coupler is connected to the negative of the two switch terminals.
Make sure that pin 4 of the coupler is connected to the 0V of your circuit.

Tried that and it still does nothing.....???

 

ive taken some readings from the coupler.

across pins 1 and 2 im getting the 15.6v

across pins 4 and 5 im getting 0v

when the buttons are pressed getting 0v across 1 & 2 and 0v across 4 & 5.

 

ive taken some readings from the coupler.

across pins 1 and 2 im getting the 15.6v

across pins 4 and 5 im getting 0v

when the buttons are pressed getting 0v across 1 & 2 and 0v across 4 & 5.

Both of those readings are incorrect.

Between pins 1 & 2 you get ≈2V, and 0V when the button is pressed. The readings suggest that either pins 1 & 2 are connected the wrong way round - pin 1 should be positive of pin 2 - or the coupler is damaged. Check that pin 2 is positive of pin 1. If not swap the wires.

Between pins 4 & 5 you should have 9V when there is no voltage between pins 1&2. Again 0V in this condition suggests either incorrect connection to the counter circuit or a faulty coupler. If the coupler is in a socket, unplug it and you should get 9V between pins 4 & 5 if it correctly connected.

 

Success! its all working. It was a bad connection between the main board and the coupler.

Id just like to say thanks so much for all your help Albert.... I couldn't have done it without you

 

A pleasure.
Mind you, I still don't understand the original double counting problem...