Just thought I'd start a thread about a little idea I had this year for my maze. I run a large PA style setup in my maze for the ambient sound and sound effects. I needed a way to make my props trigger the computer to play the sound effects at the right time, since most of my props were home made and didn't have any "built in" sounds of their own.
I was initially going to use an Arduino to interface with the computer and take a bunch of signals from the props and turn them into keyboard inputs on the computer and in turn, play the sounds. I realised 3 days before Halloween that the Arduino I had ordered for the job wasn't going to be able to do what I thought it would initially, so I had to find another solution as I didn't have the time (or funds) to buy the right Arduino for the job before Halloween.
I decided that my best bet in the time-frame that I had, was to buy the cheapest USB keyboard I could get my hands on, and solder wires to the buttons from my props to trigger the sound effects. Well to my surprise when I pulled the USB keyboard apart it was nothing like the old ones I remember for when I was a kid! Just a tiny little circuit board in the top corner and two plastic sheets with traces on them leading to all the buttons. This had the potential to be an awful lot tidier than I thought it would be!
The board has a series of pins on it, some labelled with an R followed by a number and some labelled C with a number. After following a few traces I soon worked out what's going on. The keyboard is divided up into a grid, and the C numbers are Columns and the R numbers are rows, jackpot! All I need to do is hook a row number to a column number and the PC reads it as a button press. With that in mind, I quickly soldered in some wires for the first 4 letters of a row (A,S,D,F) knowing that would be enough for my haunt this year, shoved it all in a box and got to work on the next job.
Over the next few weeks I'm going to turn this into a proper little interface box for my PC, using some cheap 3.5mm Mono jack connectors and some prototype board and have the potential for 100+ separate inputs! (I'll probably only do 20 or so, since I don't see myself ever needing that many different sound effects).
I'll take some pictures as I go and write up some instructions here, for those of us who are less technically minded