Converting an old laptop keyboard to a USB one

[electrotwelve]

I owned a Dell Studio 1450 keyboard a while ago. Its now kaput but its keyboard is the best one I've used so far. I managed to get the keyboard out and I see that it has a 30-pin 1mm pitch flat cable to it. Can anyone guide me on how I can go about converting this keyboard to a USB one? I tried see how the rows and columns are arranged but it looks like the cable contacts are carbon coated and the repeated multimeter probe touches were scuffing it. Also, the first and last pins on the cable seem be internally connected.

EDIT: Links to the original large images:
https://i.imgur.com/78RCvfEm.jpg
https://i.imgur.com/OwDfJiMm.jpg
https://i.imgur.com/cVB31h1m.jpg
https://i.imgur.com/Y8aNO3Gm.jpg

[suicidal_orange]

Your pictures aren't big enough to see much - can you see any of the traces under the keys?  If not you'll have to work it out, any coating will be burned off when you solder wires to the connector so no harm scratching them but I think it would be easier to solder the wires now and plug them into a breadboard with a Teensy (or whatever you're planning to use for the controller) Or if you're planning on buying a break out board (no idea if they exist) you could attach and poke that.

Does the keyboard have LEDs?  Trying to understand what the second small ribbon is for.

[casualdehid]

Your pictures aren't big enough to see much - can you see any of the traces under the keys?  If not you'll have to work it out, any coating will be burned off when you solder wires to the connector so no harm scratching them but I think it would be easier to solder the wires now and plug them into a breadboard with a Teensy (or whatever you're planning to use for the controller) Or if you're planning on buying a break out board (no idea if they exist) you could attach and poke that.

Does the keyboard have LEDs?  Trying to understand what the second small ribbon is for.

Dell had quite a few backlit models. This might be one of them.

[electrotwelve]

Your pictures aren't big enough to see much - can you see any of the traces under the keys?  If not you'll have to work it out, any coating will be burned off when you solder wires to the connector so no harm scratching them but I think it would be easier to solder the wires now and plug them into a breadboard with a Teensy (or whatever you're planning to use for the controller) Or if you're planning on buying a break out board (no idea if they exist) you could attach and poke that.

Does the keyboard have LEDs?  Trying to understand what the second small ribbon is for.

The second cable is for the backlight. I have an adjustable power supply and I’ll slowly start supplying power from 3V onwards to see at what voltage they light up. On the traces under keys, I really can’t say. I will have to peel off the white backing to do that. But that would sort of destroy the keyboard. I’ve ordered a few FPC connectors with that pitch but I don’t know how to tell the rows from the columns. Is it 15 rows and 15 columns?

[suicidal_orange]

Going blind it is then!

A 15x15 matrix would be big enough for 225 keys but the end two being connected loses at least one, probably both.  It will be a lot of trial and error to work it out especially if it is nearly equal rows and columns with lots of gaps but it's doable.

Are you a programmer?
 

[electrotwelve]

Going blind it is then!

A 15x15 matrix would be big enough for 225 keys but the end two being connected loses at least one, probably both.  It will be a lot of trial and error to work it out especially if it is nearly equal rows and columns with lots of gaps but it's doable.

Are you a programmer?

I know C and fairly well versed with the Arduino flavour of CPP. A little bit of Python.

[suicidal_orange]

Arduino is perfect (assuming you have one unused)  Set a pin as output and connect it to your chosen pin on the cable, set lots of pins as inputs and connect them to the cable starting at the other end.  Loop through checking the inputs (or use interrupt pins if you have enough) and print the pin name when it goes high.  Then you can press keys and record them in a spreadsheet with the number of the output pin on the cable down the side and input across the top with the key names in the middle.

Hopefully all the rows are at one end and the columns the other, that would make it easier.

Actually would this be automated?  Connect every pin on the cable to a pin on the arduino, press all the keys by putting something heavyish on the back of it then set each pin high and scan the others.  You wouldn't know which key was where but would have the rows and columns.

[electrotwelve]

Thank you. This makes sense. I will report back once I have the data or if I run into any snags. Whats throwing me for a loop is the two ends being the same electrical connection. Wonder what's that for.

[yui]

some actually made a firmware to scan the matrix of those laptop keyboards, i saw that browsing instructables a while back:
https://www.instructables.com/How-to-Make-a-USB-Laptop-Keyboard-Controller/
seems to be exactly what you want to do, and he did quite a bit of the trial and error already.