HP Compaq IPAQ G750 Keyboard to USB

I saw a gif of this keyboard a couple of weeks ago on Reddit so decided to buy one and modify it to work on my PC instead of the pocket PC it was designed for. So here is the first tutorial of someone doing this with this keyboard (according to 2 days of searching the internet for people that have done it).

Step 1: Collect Components

Circuit:

• 1x MAX232
• 4x 1uF Capacitors
• 1x Arduino Pro Micro

Case (Optional):

• 4x 12mm M2.5 nuts & bolts
• 1x Top (3d printed from STL file)
• 1x Bottom(3d printed from STL file)

And last but not least the HP Compaq IPAQ G750 Keyboard

Step 2: Take Keyboard Apart

First, remove the screws on the top and bottom as shown in the first 2 images. Then the top panel should be able to be removed to expose the internal circuit and disconnect the top connector.

Then remove the 2 screws on the underside of the connector to allow you to remove the circuit board with the connector on.

Step 3: Circuit

First, locate the wires attached to the connectors circuit (as shown) then remove them from the board. Then extend these allowing you to attach them more easily later (about 15cm of wire should work fine).

After extending the wires put together the circuit as shown in the images or download the Fritzing sketch.

Step 4: Hardware Box

After building the circuit glue it into place inside the project box (STL files in step 1) and make sure the keyboard connection wire pokes out one end and the micro USB is accessible through the hole in the other. I would also advise you to use a bit of hot glue around the wire to stop it from pulling from the circuit.

Then secure the box together with the 12mm M2.5 nuts & bolts and upload the code. To compile the code and upload it you will need this library https://1drv.ms/u/s!AsnDQhGk8mt6iPoEJWfPQ1Y9vFeNuA?e=4QgT3A

Step 5: Finishing

Now screw your keyboard back together, with the connector poking out where the connector used to be (as shown in image).

Then connect all of the pieces together and plug into your pc, and if you followed everything correctly it should work.

Comments

[magnetica_]

what would be the length height and width of the circuit?

[styxomat]

What an awesome build!!!

I would like to mod my Compaq keyboard too and I already have the parts.
Unfortunately I can´t find the hashmap library :-(

Could you tell me where to get it?

Thanks a lot and best regards.

[rtm516]

I have updated the link to the HashMap library as the original has been taken down.

[chromax]

A great solution. Had the same idea, when I saw this old keyboard. It is a timeless piece.

But isn´t the best thing about the keyboard, the foldability, no possible anymore with the big box?

[IanM102]

Is the keyboard connector a multiplexed connection? Or does it have an on-board chip for retrieving keyboard input and sending it to the south bridge through a different method?

[rtm516]

I have just looked at my history and I think the microcontroller was the EM78P447SAM

[rtm516]

Its got an onboard microcontroller, cant remember which one.

[Penolopy Bulnick]

Great mod, thanks for sharing :)