Integrating Apple trackpad into custom keyboard?

[kbder]

I've been thinking about designing a keyboard which has a built-in trackpad, and it turns out you can buy a replacement Apple trackpad module for about $30!  https://www.ebay.com/itm/Trackpad-Touchpad-for-Apple-MacBook-Pro-13-A1278-2009-2010-2011-2012-MB990/323026073821?hash=item4b35dab8dd:rk:24:pf:0

Question is, has anyone looked into how to connect to one of these things?  connector pinout, protocol, etc.

[xack]

I think there you have a lot to reverse engineer, since apple as we all know likes to think different 
How ever I think i would have a look at something like https://www.hackster.io/BuildItDR/arduino-controlled-usb-trackpad-f443a6 and go from there.
Its not an apple track pad but I think it helps to understand how they work and interface in general before going ahead.
What you wouldn't find here (I think) is someone saying "just buy that plug and you are done". It might involve blood, sweat and tears

[hanya]

Apple's touch pad uses custom IC to read electrostatic capacitance from the pad. I could not find datasheet for the IC.
Linux uses synaptics driver on Mac PC.
I forgot well about the IC but it might be Broadcom BCM5974 which reads electrostatic capacitance. If so, you can find some driver code in the Linux kernel.

Some people successfully converted old 4pin touch pad into USB touchpad. But recent one has 22 pins. It seems the USB controller is placed on the mainboard for recent version.