Hacking a USB Keyboard

How to hack a USB keyboard or any keyboard for that matter. Send inputs into the computer without a pesky microcontroller.

Step 1 Open up the keyboard

Open up the case. You can use a screwdriver or an any ridiculous looking multi-purpose tool. Sometimes even after all the screws are removed the keyboard still won't open up. In this situation, don't worry, just forcefully pry the case apart with your screwdriver. It doesn't matter if you break the case. You don't really need it.

Comments

[tedino]

Hi!
That video u mentioned on http://a.parsons.edu/~randy/video/typewriter.mov is down due of Inactivity. Please send new video and url please.

This was good tutorial :) i wanna see that video and i wanna try making own version of Typewriter perhaps :) Need motivation and wanna see that video :)
/ted

[cspoelstra]

Thanx man, I was wondering for a wile to make such a thing as a cheap replacement for a midi controller for my DJ setup.. How about the switches you can use, is there an resistance problem ?

[vikingberserker]

BRILLIANT!! Thank you, you have no idea how much this one helped me!

[thomkrauss]

So another question...
Basically I'm using this hack to control an electronic drum set that I'm trying to make using the alphabet characters as triggers. The program I'm going to use seems to allow simultaneous hits.
My question: How do I wire it so that one button will trigger two different letters at the same time? My thinking is that if I wire two letters together, the board will be confused, this sending the wrong signal or no signal at all.
Can anyone explain what should happen? I'd like to address this before I try to build this and see that it doesn't work.
Thanks!

[randofo]

Most keys cannot be pressed at the same time. There are a few exceptions though, which include 'shift', 'option' and 'control' (for example). You will need to experiment with the special function keys to get the ascii combinations that you need.

[poita]

Thank's dude that's an awesome instructable. I just found this site and haven't joined for full access yet so I copied andpasted it all into ms word.

I use a music playing program on my pc called 'HappyEO'. It let's me press mulitple keys at the same time to play chords etc.
On a related note. When I the program on some computers I get a delay when i press a key. I was using it on my 7 year old computer running XP and it was instant. When i installed it on my friends pc with windows 7 I got the delay from when I pressed a key to hearing the note. same on laptops running Vista and recently on a laptop runnin XP. Do you think it's something to do with the secrurity software that might be on the pc's?

[thomkrauss]

Well I got lucky! I was able to tweak the free program that I'm going to use to produce the drum sounds. I was able to record the sound of the kick and crash together on a free audio recording program and then save as a wav file and map a keyboard character to that new recorded sound. I'll then just connect my button to that new letter.
Thanks for giving me the need to keep looking for an answer!

[thomkrauss]

Is it safe to say that I should only use each pin once, to keep the wires and the board free of excess solder? I'm trying to use this method to build a set of drum triggers, an entire kit of drum pads, and want to know how many inputs I would end up with. The more I can get the better, I just want to see how limited I would be. I guess I could use two keyboards if it really came down to it.
Also, will a piezo attached to these pins work and will it produce two "keystrokes" for each hit as I've seen mentioned?
Thanks for the great instructions, and thanks to all who contribute and answer all the questions out here.

[randofo]

You would use each pin once, but you can then connect the wires to another circuit board where you can connect multiple wires to each one. By doing that, in theory you can get the full keyboard. See the mess of wires here:
http://www.instructables.com/id/Typewriter-Computer-Keyboard/

[thomkrauss]

ok then my next question: if I were to connect multiple female RCA jacks to 2 pins on the board (to enable the "shorted connection" and "type letters") and then at the other end took a button and connected that to a female RCA jack and used male to male RCA cords to connect the junction boxes I make, will pushing the button make a connection and "type letters" or is there too much wiring going on?

[randofo]

Sounds reasonable.

[smoak]

I'm trying to put this into a custom controller. Simply using 12 keys, random if need be. Which side is side A and which is side B. My guess is that the top layer is side A and bottom later is side B. Would I be right to assume this? I'm hoping it would save me the trouble of having to trace, I have terrible eyes.

[dimitrisa10]

what will happen if you connect three pins will it display 2 characters because i'm making a hand-top out of a pico itx board and im wondering if i can use this to make a thumb keyboard

[randofo]

If it is a function key or the shift key or something like that, it might do something. Most likely, it will not do anything (or nothing you would want it to do). It won't make two characters.

[dimitrisa10]

thx for the info do you think it would work though for a tiny keyboard

[currently_awake]

keyboards send two scan codes for each key hit. One for each key press, a second for the key release. (the second has a bit set to mark it as a release). All the keys on the keyboard work this way, even shift and control.

[snag46ed]

Great Instructable! I'm a little confused though. So all we need to do is wrap the wire around to the corresponding pins and GLUE them down, or SOLDER, or does it matter?

Also, I'm trying to build one with one simple function...I want to make a big "Easy" button, or something like an "Easy" button send a space bar input. Would I follow the steps in this instructable, connect the "free" side of the wires from the modded keyboard controller to a prototype breadboard, and connect the leads of the Easy button to the breadboard where the wires from the keyboard connect?

So basically keyboard controller -> Prototype breadboard <-Easy button...?

Thanks so much!

[snag46ed]

I'm kind of a noob when it comes to hacking electronics, fyi :)

[thealeks]

very nice instructable! im about half way thru hacking a keyboard of my own and this has helped me immensly! my hack is a little different tho. ill post an instructable soon!

[capth00k]

I tried to make this hack work with an old PS2 keyboard I had laying around -- to paint the keys on it and use as a synth controller on my mac - even got the PS2 to USB wiring worked out but it lights up and doesn't allow me to input characters ; nor is is recognized as a USB keyboard. I think there may be a USB device controller that PS2 boards doesn't have ; so perhaps changing the first page 'USB or (any) keyboard can be converted' should be changed if there isn't any way to make a PS2 one work. Here's the controller I pulled out of the old PS2 dell quietkey : The PCB is 123452 REV J ; the large IC has the following markings: nmbk15r4286 std5a8d bh 124200-002

[Lee Wilkerson]

You are absolutely right about the USB device controller. All USB devices have controller chips - that's how the OS recognizes that a USB device has been connected. ~/Lee

[I MAKE STUFF]

another use of this is to add switches to flight sims such as fsx, fs2004 ect.

[jibatsu]

on my keyboard, multiple keys are on the same pin e.g. the left key and the enter key, do i solder double wires onto the pins to connect to 2 keys. will they both work independently?

[randofo]

Yes, multiple keys will be on the same pin. The key presses are created by connecting different pairs together. So, for example, one pin on "Side A" might connect to eight other keys on "Side B" to make eight different key presses.

[jibatsu]

so i only have 1 wire to each contact. amirite?

[randofo]

Yes, but you would want to connect that 1 wire to each switch that you are looking to add. So, if left and enter go to the same pin, that 1 wire would connect to both the left and enter buttons.

[jibatsu]

all i need is L shift, S, enter, left, up ,down, num enter, num +, num - i followed the tacks back to the pins and marked them, how do i then wire it up as i have more buttons than pins.

[KarateLover21]

I am hoping to make a controller for scratch. I am making arrow keys, ZXCV and space.

[DackMilk]

HOW ARE THE "ALT" AND "SHIFT" KEYS IMPLEMENTED?  THESE SIGNALS ARE NOT SEEN BY MY COMPUTER IN ANY WAY BUT PRESSING THE GOD DAMN SHEETS OF PLASTIC TOGETHER!!!

[Fuingurth]

well apparently, the CAPS LOCK key IS recognized

[electronic boy]

i have a usb keyboard and have tried to solder wires on but the contacts are like half a millimeter apart i am using a 12 watt soldering iron and i am neat at soldering

[Madrias357]

Try using just a little less solder. I've found that to be very useful.

[electronic boy]

Thank,s it worked very well and i went on to mod a wireless one and made a controller

[hacker3455]

 Is there any visual way to tell if you fried your keyboard PCB?

[randofo]

It stops inputting letters into the computer.

[hacker3455]

well i know thats not working, just wondering any dis-coloration in the board or something to that extent that would be an indicator. Guess i need to get a cooler soldering iron and a new keyboard.

[xM4ST3R SHAKEx]

is that the way you read the pins on side b? right to left?

[denis10k]

A very easy way to find out which pin goes to which button:
Put one of the layers on a image scanner, scan it and fill the lines with different colors using the fill tool. Took me only 30 minutes to get the entire pin layout

[Javin007]

Insane.  I had absolutely no idea that a keyboard's guts were so simplistic.  I've created numerous toys/devices and have always been lacking for a way to design my own input method that didn't involve some complex crap with an arduino<sp?> device or something. 

My latest attempt was going to be a large MAME machine, but I was scratching my head on just how to deal with the inputs.  Trying to stick a full-blown keyboard into the device just to have the buttons press the keys seemed a bit hacky at best.  This is awesome.  Now I'm just TRYING to figure out what all I want to make with my extra keyboards.  I even have some wireless keyboards that I could see using to do some fun stuff with. 

[ratgod]

I've had a similar idea, I was going to use an old PS/2 style keyboard as an arcade joystick interface, I have the board out and mapped the keys (I shorted the sequences while plugged into an old laptop, but your way seems much better).
I was going to build a MAME cabinet using it, but never got round to it.

very good instructable.