Computers & Mobile Technology
HOW TO – Convert a laptop keyboard for desktop use…

1.Laptop KeyboardChris writes in with something to do with a laptop keyboard: “Ever wanted a laptop keyboard to use with your stationary computer? Lee Char did and took a keyboard from an old Compaq and ‘converted’ it to be connected to his regular computer. This is something that would be interesting to spin further on by interfacing this keyboard with an PDA instead, like an iPAQ. Anyone have an idea on how to do this?” Link.

13 thoughts on “HOW TO – Convert a laptop keyboard for desktop use…

  1. The key point to remember in integrating keyboards is that PC keyboards are basically just arrays of switches arranged in a grid with an intelligent controller. The keyboard controller pulses each row and reads back which column, if any, responds and thus figures out which key is pressed. The keyboard controller then sends the appropriate scan code to the PC down the cable which is a serial link.

    The PC’s keyboard controller also responds to some commands from the PC to signal that it is working and other commands like turning on the LEDs on the keyboard. i.e when you press NumLock the keyboard controller sends the scan code to the PC and the PC responds by telling the keyboard controller to turn on the Numlock LED.

    So, to use a PC keyboard with another device, you probably have to throw out the keyboard controller circuitry and make your own one that scans the keys and transmits the pressed keys back to the new device in the format that it expects.

    You might be able to just replace the keyboard’s keyboard controller chip with an EEPROM/Flash ROM chip of the same type and write your own firmware but that is a daunting task.

  2. Bummer. Site’s still down, and I have one of these keyboards sitting here on my shelf looking for a project, too. Arrgh!

    I wonder if the pinouts for the keyboard would just map simply to a PS/2 connector?

  3. Lee Char did and took a keyboard from an old Compaq and converted it to be affiliated to his approved computer. This is something that would be absorbing to circuit added on by interfacing this keyboard with an PDA instead.

  4. I will be working on this very project, and have some experience making an arcade cabinet using a keyboard controller IC into a joystick controller. In my case, I want to recycle a keyboard from a Dell netbook. I have a few Dell PC USB keyboards that I can tear apart. If the ribbon cable pinout and size is the same, I might have luck simply using the connector / controller from a standard Dell desktop keyboard. If it works, I’ll let you know!

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