IO, IO, it's off to work we go... Sorry. Really, I am.
Anyway, since I only have 1 4B, I need to get it into a functional state. This means it's IO time! The original side IO (and each's intended fate) will be listed here:
1. 1x Firewire: change to external HDMI
2. 2x USB ports: Use as... USB ports
3. 2x 3.5mm jack (mic and headphones): audio output
4. Charging port: charging! (this part is exciting)
5. Ethernet port: connect to Pi's GbE
6. mini-DVI: nothing, maybe a button
As you can see most of these things are well on toward their fates:
And I will be harvesting the original connectors for 3.5mm jacks, the USB, and the charging port.
The USB and 3.5mm ports are already hooked up, as well as the HDMI port. I made my own connectors by stealing ones from HDMI adapters.
Part of the goal of this project is to make it as indistinguishable from the original as possible - and that is why this is my favorite part. I took the guts of a USB charging brick and put them inside the Macbook charger - so now it outputs 5V and I can use the original magnetic connector. Apparently the LED on the power connector is controlled via 1-wire serial, but I've never used any kind of serial on the Pi before, so if anyone who reads this has any information, I would love to hear it.