LPT1 attachment

[lyle]

Hi Guy's,

Can anyone out there help me with this? I will try to be as explicit as possible

I have this peripheral that connects to the PARALLEL PORT. It is controlled by a qbasic program.

The QB program monitors 8 inputs on this device and gives the expected response when a digital 0 test signal is applied to any one of the 8 inputs.

So the device works great, NOW, here comes my question!

Does anyone know of a circuit that can receive a signal from a wireless motion detector (or similar device) that will (when activated) cause a digital 0 to be applied to one of the inputs, thus triggering the PC to give it's heads up warning for that zone?

I just don't have the expertise to solve this one on my own, so any suggestions of how this might be done will be received greatfully.

Lyle

 

[cr0sh]

A digital 0 (logic LOW) is simply pulling the pin to ground; if your motion detector or other device can activate a relay, that relay could be connected so that it grounds the pin (switches the pin from 5V - HIGH to 0V/gnd LOW - by connecting the pin from a 5V pin on the parallel port to a ground pin on the port). That would be the "dead simple" way to do it. You could also switch the line to ground using a transistor (PNP, IIRC)...