Hey everyone,

So I am doing this computer engineering class project where we have to use a parallel port of a computer to read inputs and make a program that acts according to that input.

The project is to make a high rise building(or a mini city in my case) that has sensors (to detect opening of doors or windows). For me, this is somewhat difficult because I have like 21 sensors that require 21 inputs on the parallel port. But, I can only use four of the five available.

I decided to "send" a 4 bit signal to the four pins on the parallel port every time something unwanted happens. So it would send like 1100 or 1101 or 0100 or 0010 etc and the parallel port would come up with some random number that corresponds to this signal and the program will act accordingly.


When I thought of this, I though like to "SEND" the signal to the parallel port. But, the city that we made has all the sensors that "STOPS" sending the signal to the parallel port. Basically, if everything is fine, the circuit is complete and the inputs are received.

And if someone breaks into a building by opening a retractable roof door, the circuit breaks and the parallel port should receive a unique signal.

So should I wire this in a series circuit so that the first input pin on the parallel port connects to the first input wire that is connected and then the ground from that goes to the other first input wire in another building and the ground from that goes to the ground in the parallel port so that if anyone breaks then the entire circuit breaks?

Or should I connect all the first input wires together and connect them to the first input pin from the parallel port?

I hope this makes sense to someone... because the problem is, the model doesn't send the 4 bit signal when something happens, but it stops sending the 4 bit signal to the parallel port...

Hey there DJE,

I am not all that good with programming Parrallel ports, but I will try to help. I would say that you probably need to try and recoonfigure either the port to react when the signal is interrupted or the sensors in the city to only send a signal when something happens. This is where I believe your problem is.