I had to tear my Variac apart today because the wiper was missing on bits.. I gave it a solid cleaning got rid of some rust on the case. I used alcohol to do the cleaning.. worked out great. I don’t use my Variac as much as I used to.. in fact I nearly got out of the hobby over my very first. When I was 14 I understood what transformers were and I had been playing with very high voltage (neon transformers)… I wanted more voltage so I thought I might test the insulation a bit. Seeing as I didn’t have any good way to get more voltage I thought I’d just flip my primary and secondary around running my secondary in the 80~110 volt range. Well.. that doesn’t work out so well. My variac was on it’s side and at about the 2 o’clock position.; it blew out every winding from 2 o’clock down to 6.. I had issues plugging things in for a while after that 😀
I eventually got over that out of necessity. I used/use variacs for powering up old electronics… it kind of works the old caps in before you hit them hard… filaments as well. Today I was using mine to lower the input to a linear power supply to find the approximate drop out voltage of a piece of equipment; that was in interruption of what I was really doing in my shop.
I pulled my Roomba off the wall. It’s an older 400 series I got for dirt cheap on eBay. A friend of mine at work challenged me to a Roomba Sumo contest; no winner… I think he is still working on his 🙂 My first, current, version is based on two PICs, a 16F628A and a 18F2331; both written in assembly. Well it’s okay.. but I think I can do better. I did the PCB in deadbug… ASM was okay but it takes much longer to develop and making any code remotely tricky is a chore. So this time I think I’ll develop a custom PCB and write it all in C. This new makerspace I’m co-founding looks promising so maybe I’ll sucker a couple of people into joining in the fun.
I’m re-accomplishing all my sensors; ditching my hardware-happy comparators and going with all A/D. I also never added in switches for my bumpers.. they were pushbutton microswitches on the only mainboard if I’m not mistaken… I’ll figure something out.