Using Laptop Keyboard for Raspberry Pi
Raspberry PI is a pocket-sized PC that is used for handling simple to complex computing tasks. You can use the credit card size chip to browse the web as well as to learn python or other programming languages. Although Raspberry Pi is not used as a commercial product, users can try it out for a different experience. Connect a monitor, keyboard , and mouse with the chip, and you are all set to ...
The open source btferret project is how the Raspberry Pi 500+ can be used as a regular Bluetooth keyboard , with input sent directly to other devices and operating systems, like a laptop , tablet, or a monster gaming rig.
Connect Raspberry Pi to your Laptop screen and Keyboard
Learn how you can use Laptop's screen, touchpad and keyboard as peripherals for the Raspberry Pi using the VNC Server. Find this and other hardware projects on Hackster.io.

The long answer: thanks to the I/O pin-outs, you can interface literally any electronic controller, microcontroller, sensor, component, or device you can put your hands on with a raspberry pi and basic programming knowledge (you gotta know how to make drivers unless you know someone else that can /will or find a pre-existing driver for the device).
Connect Raspberry Pi to Your Laptop Screen and Keyboard : Learn how you can use Laptop's screen, touchpad and keyboard as peripherals for the Raspberry Pi using the VNC Server.
I have a laptop (dual boot Linux/Windows, if this could help, and with both USB-A and USB-C ports). I also have a Raspberry Pi 5 ( I just received this starter pack for my 42nd birthday). I don't have a spare keyboard (basically the last desktop PC I used was 15+ years ago, and I'm pretty sure it used a PS/2 connector).
Using a laptop keyboard and trackpad with a raspberry pi Solved Given ...

The keyboard uses a standard ribbon cable and the trackpad uses a really small version of it, with a purple tints (don't know if this info is needed) Anyway, I could put a Pi inside it and use it as a homemade Pi 400.
I have an old laptop keyboard like the one shown below: It has a 24-wire flat cable coming out of the back. Would it be possible to use this as a keyboard for the Pi ( I assume with some microcontroller in between)?
How to Install On
Learn more One of the greatest things about the Raspberry Pi is how small a computer it is . But if you want to keep it compact by using a touch screen, or if your Pi doesn't have a keyboard , how can you type? In this situation, an on-screen or virtual keyboard can be very useful.
Meltwater has come up with a nice little trick which allows you to use your laptop or desktop's display and keyboard as the display and keyboard for your Pi . You won't need to do any soldering or to buy any special equipment: all you need is a network cable.