One of the most powerful coding / computer platforms I have come across is the Raspberry Pi. It allows for complete transparency in how the computer works from the hardware to the software and everthing--like robotics--between.

https://www.raspberrypi.org/

It is an afforable SOC (system on a chip) that comes with a Linux distro (operating system) that can be customized to do nearly anything a mid-range computer can and then some. It can have a tiny bread board section for attaching mechanical devices, ports for making it into a PC, and can be hooked up with others to scale up rather powerfully too.