Reply to building a custom midi controller

Hello again. today i am reaching out to you guys in the hope that you can help lead me in the right direction on how to build my own midi controller. I would like it to be small and along the lines of ean's dj 101 but with 6 buttons and more knobs. I'm gonna be mapping it to tractor to control some build/ sweeping effects i have made and to control other miscellaneous stuff ill come up with. i just want it to be small and compact and easily transportable. i currently have a s4 mk2 and a spectra and want something that sill fit perfectly into that set up. If you guys have any better ideas or can point me in the right direction i would greatly appreciate it.