keyboard
I'm trying to make this simple code lock circuit, and I ordered this keyboard for it.
However, there isn't any kind of manual for it, and I simply don't understand how it works.
Here's a larger picture of it (sorry for the horrible soldering, I've a bad solder, and I probably do it wrong also.)
So there's 7 wires on it currently, but how do I actually use this thing?
Plenty of info on the net? What did you Google?
http://www.computer-engineering.org/ps2keyboard/
Use command 0xED
For electrical connections
http://www.arduino.cc/playground/Main/PS2Keyboard
The PS2 keyboard is a bi-directional serial line, use same wire to transmit and receive
What you're likely find for a typewriter keyboard like this is that the keys are simple buttons in a matrix arrangement like this taken from this page about Commodore 64 hardware:
Of course it won't be the same layout it's just to give you an idea of how it's likely to work. To determine the layout you could set your multimeter to continuity check mode (hopefully it has a beep mode) and systematically measure the continuity between pins as every button on the keyboard is pressed, it looks like you should be able to access the pins with the multimeter probes but it'll probably be a two person job so someone else can run through the keys.
It'll be quite tedious but you'll probably find the matrix follows the physical layout of the keyboard somewhat. For example if you start by measuring every combination to find what is shorted when Q is pressed by measuring pin 1 followed by the other 16, pin 2 followed by the other 15 etc and write down the result and then move to W which is to the right and A which is below you should find some sort of pattern starting to emerge so you can work out what the rows and columns are.
Best Answer
There are four rows and three columns which make a matrix of 12 possible connections. Each switch is located at one of the cross-points of the columns and rows: -
If you "read" the value of the voltages on a single column and activate each row with a positive voltage (not together but in turn) you can deduce which of the four switches is pressed in that column.
Read the voltage for each of the three columns and you can deduce which button is pressed of the 12. Two buttons being pressed can confuse things so be aware of that.