First you need to check the revision of your console because the trimming guide for the ps2 use a specific revision:
The Definitive PS2 Trimming Guide | BitBuilt - Giving Life to Old Consoles
Check it for be sure.
Next,you will probaply an Uamp2 from 4layerTech and a ps2 voltage regulator board like this one:
Release - Ps2 voltage regulator board | BitBuilt - Giving Life to Old Consoles
You also can use the open source project from
@Gman (the ps2+)for the controller here:
GitHub - Gmanmodz/Ps2Plus: PS2 controller emulator designed for the PIC16F18876
You also need a Free McBoot card for hacking the ps2,but you can buy it on ebay for 10 bucks.
And you need to launch you into 3d modeling and pcb design because I don't know any portables ps2 who is open source.
P.S:I probably forget some other things,please check the documentation and other ps2 worklogs.
Hope it's useful