IR circuits connected to counter don't work proper

Hi,
I've got 4 of an IR emitor-detector circuit which are to be
connected to a single counter circuit.When I connect
each emit. det. circuit individually to the counter,
it works almost perfectly(each crossing produces one
count) but when I parallel all the four and connect them
to the input of the counter,things don't work as perfect.
At the beginning,each crossing makes one count but as
time passes one or two of the relays go through a
phase in which they don't make any contacts when the
related IR beam is broken.Moreover,one crossing of an
IR makes 2 or more counts on 2 of my circuits.
What could be the problem when I connect them all?
Any comment whould be highly appreciated...
Regards,
Gazal

Posted by gazal on 29/11/2003, at 07:38 GMT

IR circuits to Counter

I would connect the IR circuits to the counter via schmitt-trigger stages. Schmitt-triggers are used to help clean the signal up by getting a definate logic switching level especially where slower acting circuits such as photosensors are involved.Any other causes I would look at are logic supply decoupling and any interference (motor suppression) to the logic signal.

Posted by Robert Neill (varient412@yahoo.co.uk) on 13/01/2011, at 16:46 GMT