When you say "using an FPGA is not building from scratch", what do you mean by that?
Building from scratch would be to grab a box of transistors and start welding them together - same as what's being done on a wafer.
would it be easier (and shorter) to use an FPGA and go from there?
Yes, you can even download softcores
so that you have to do next to nothing yourself, but that would sorta go against the whole idea of building it yourself I'd guess:
You might wanna check out this page
and this page
(both on the FPGA subject).
A page on a TTL build-up here
and a discrete transistor build 4-bit core here
In the end, i want to create something that i can use in a very very basic robot. something that could just move around and hit a wall for all i care. However, i don't want to go out and buy already made pieces and just connect then and it's done. I want to at least do SOMETHING in the most important part of the robot imo (the MCU). Any ideas from what i explained?
Whatever your fancy!
Personally, I find it a waste of time these days with cheap controllers everywhere (but I'm probably a bit biased, as I built my first real computer from a Z80, some handfulls of Z80 support chips, a truckload of LSTTL chips resistors caps etc. and on a separate PCB, a huge 48kB RAM, all in all taking up about twice the space of a modern motherboard. That was back in the seventies)
, but each to his own
But getting a ready bought cheap microcontroller to work takes a wee bit more than just buying it and popping it into a board and might teach you something useful in the process - like how to decouple supply lines, how to lay out boards for analog inputs etc. etc and it still needs a program stuffed into it's tiny brain.
My best advice is to keep the interest, but do the project with a boring regular microcontroller first
(I'm sure it will be enough of a challenge initially) and when it's working perfect and all documentation is done, go ahead and make your own - that way, you can always add whatever you get around to, to the project, but if you're like 99.9% of all the students I've met, known or helped, you don't
have plenty of time, in fact, you'll sweat your brains out your ears the last month, week, day, hour etc. derived of sleep and proper nutrients (pizza only makes you fat and coke rots your guts, if you forget to water it down with some Scotch a.k.a. Brain Oil
You won't get judged on how complicated you made life to yourself or the size of your project, but on how well you documented whatever you made. Even the smartest robot will net you an "F", if the documentation sucks and even the smallest project can land the A+, if
the documentation is pristine - I've actually seen top marks for something as "simple" as a one transistor amplifier (an electronics engineering graduation exam), due to the extremely bright and complete documentation.
Cheat yourself in a good way, by setting your watch a couple of months forward - you'll be glad you did
You don't do this to have a good time, you do it to get a good future life!
P.S. The most important part of a robot is not the microcontroller, it's the power source!
Don't believe me?
You can build a functional robot without a microcontroller, but you cannot build one without a power source!