First of all thanks all for helping me out so much! Y'all are AWESOME!!!
And as for the clutch - I'm thinking of staying away from clutches, I'd rather have a servo-driven power-steering thing I think. Seems like it would be easier to implement a pot linked to the wheel, rather than trying to jam a clutch in there somewhere... I dunno, I'll look into it. I don't have a machining shop (just some woodworking tools and such), so hacking that into the steering system may prove more difficult than it seems.
Okay, so the project calls for a standalone atmega328 (for some lighting and such, maybe an actual MP3 player...). Now I'm experimenting with powering this thing (and because I don't want to blow it up, I'm using a motor as load instead of the chip) with an LM7805 and a few caps (electrolytics) and a lab PSU.
Input: 12V and something like 0.08A with the motor running
Output: 5V
So far I have everything on a breadboard, and I have an issue. Perhaps several, not the least of which is me being a total NEWBIE!...
Let's start with the fact that all of these caps are salvaged from an old PC PSU, which seemed okay, except one transistor having had a very bad day. So bad in fact, that it left a brown skidmark on the PCB and left it smelling toasty.
The input capacitor is 16V 1000uF, across the LM7805 (GND and OUT pins) I have a 50V 4.7uF, and the output has a 50V 10uF. All the polarities seem proper. The motor is a chinesium-grade hobby motor out of some dead toy, with resistance measured at around 8 Ohm.
I hooked up my scope (don't ask why I have one... had the opportunity to get it basically for free, so I did) to the input (channel 1, yellow) and output (channel 2, blue). And here's what bothers me: the output voltage has a spike at around 10V (as seen in the photo attached, note the timescale). Am I reading something wrong? Is this normal for an inductive load? Is it an issue with improperly selected capacitors voltage-wise? Capacity-wise? Electrolytics, where I should've used ceramics? Dead capacitor somewhere? Or am I just an idiot and should give up this whole electronics hobby and take up knitting and gardening (or perhaps something safer where I can't hurt myself or others)
What I'm getting at is I don't really understand capacitors. Not like how or why they work, but rather how to use them properly. Where resistance and current and voltage make sense to me, capacitors not so much. I mean I understand that they are in a way like a battery and a temporary reservoir of short-term power and all that, but the whole thing of which caps (voltage and capacitance, electrolytics VS ceramic VS film) to use in what cases - that's a mystery to me. Photos attached.