Paper Sensor

If you look at some of the reflective opto-things by e.g. Omron (E3X series) or Keyence (PZ-V series), I think you'll find something to do that. You'd probably need to glue a dummy sheet in the out tray so that you coud reliably catch the 1^st sheet and spot the 2^nd and subsequent.

Edit:

I think the E3X things only work with fibre optics - Omron certainly do an equivalent 'direct' type. I suggest you give them each a call & ask for tech help - they'll trip over themselves to sort you out.

I'd think you'd be paying ≈ £120.

This sounds like a lot of money for counting sheets of paper.

Low-tech approach would be a low-torque microswitch with a long wire actuator, or a "cheap'n'cheerful" vane operated photo-interrupter type switch.

all the copiers I have seen have sheet counters built in

Likewise.

Another way would be to count the reams taken from the stock cupboard, and do a material balance based upon the re-ordering information coming from the accounts office. Input = output + accumulation is a pet thing for Chemical Engineers....

The most common way I have seen used is a UV led and a photo diode mounted at about 60° or so to each other in the same (industry standard) package.

The led is focussed on a reflector (polished metal is more than adequate) that lies under the paper path, the LED & Photo diode are above the paper path (or the reverse!). Each time a piece of paper passes through, the IR light is blocked.

Add some signal conditioning and a transistor/relay and connect to your counter.

If the distances needed to cover are greater, then use a separate IR LED opposite an IR detector transistor, but this time, due to the negative effects of lighting at either 50 or 60 hz, you may need to use a widely different frequency for the led and filter out anything not near to this with a band pass filter......slightly more complicated, but i would not be surprised to hear that there are chips available to do this.

Most of the copiers do have recordings of no of prints printed , but are internally stored , also they have hardware support for interfacing with PC so you can have records on your computer ,but if you intend to have one by wireless on your counter you can attach a sensor like IR detector or relay switch which closses or disconnects with each sheet comming out encode it and send via infrared signal or radio signal to your device that will decode and display

Rob,

Can you please fill in a few details, here?

As others have pointed out, most copiers have counters built in - why do you need the external sensor?

John

Thanks for all your comments, you have given me a nudge in the right direction.

I can't talk about the application specifically, but yes I do know that copiers have an inbuilt counter. However, for this application a remote counter is also required.

Many thanks

Rob

all the little self serve photocopy shop have a bank of remote counters to tally the count.

someone must make them

Have you tried a Mini Microswitch?

You can input the signal via the contact close/open to your counter. It's cheap, quick and if it fails, then you haven't invested too much time, money or effort!

Also, check-out this site for important info.

www.automationdirect.com/static/specs/sinksource.pdf