atomic_fungus (atomic_fungus) wrote,

#5102: Tired of needing a vacation from my days off

On the plus side everything that must be done is done.

The Jeep's tire took $33 and some waiting to fix. I was kept company in the waiting area by the shop's cat, a friendly grey tabby which didn't like being put on the floor so soon after getting comfortable in my lap. Took maybe fifteen minutes for them to fix the tire, of course, because naturally a tire shop will have all the tools necessary for changing faulty valve stems.

Next up, Ace, for a 4L320 belt for the washer. Old one was shot--I took it off before leaving--mainly because of the dead belt crud all over it, but because the lower bearing is dying (due to water leaking past the bad tub seal) it spun and got some burned spots. Imagine my excitement.

Anyway, got that, got the makings for chili, then came home and put the belt on. The spin cycle runs right up without any slipping--no idea how long that will last--and I can finally stop working on anything I don't want to fuck with.

This is progress.

* * *

So with everything else that's going on, I've been looking at Hackaday which is where I got the idea to start tinkering with microcontrollers. I've been looking through hundreds of pages of older entries there--I'm in the high 700s right now--and I've seen a lot of interesting things.

It's got me thinking that perhaps I could build a temperature-controlled soldering station. The hardest part is sensing the temperature of the iron; there's probably a half-dozen good ways to hook a thermocouple to the iron so that it can sense the tip temperature, then feed its output to an analog to digital converter (ADC) and feed that to a microcontroller (uC).

The thing about the typical uC is that it makes computer control so cheap it simply doesn't make sense to do things any other way, and then you have so much leftover capacity that it can lead to feature bloat. Sensing a temperature and turning a TRIAC on and off (controlling power to the iron) will take almost nothing from a unit that can be used to display HDMI video.

I've already started piecing the thing together in my head. A relatively inexpensive iron will do; I can use the clickwheel from a spare mouse to set the temperature (and that won't tax the uC, either). A few 7-segment displays for temperature, a couple LEDs for power and other indicators. A relatively simple regulated 5-volt power supply for the electronics and of course a mains pass-through for the iron itself, switched on and off by the uC to retain the set temp. The temperature resolution does not need to be all that fine--25° per step will do, I think--and calibration can be done with a $25 laser thermometer from Harbor Freight since it doesn't need to have a hell of a lot of precision. Mainly I just want to build something nifty like this because I can, and I haven't in a long time...and because having a decent soldering station is nice for doing other work.

...and if I need better temperature resolution I can change it to suit myself since I built the thing.

Mostly, Hackaday has reminded me that I have a lot of technical knowledge that I worked very hard to gain, and even if it's not going to make me any money perhaps I can have some fun with it. And I can't help thinking that if I was able to add that to the "personal" section of my resume ("electronics hobbyist" or the like) it would help me get a better job doing something technical. You know?

These days you can get an oscilloscope for not a lot of money, too--it's not going to be a super-high-zoot digital scale with ultimate precision and all the gewgaws, but where a basic scope used to cost $500 you can get one now for under $200. Scopes are powerfully useful tools if you're going to screw around with electronics, and I recall from my school days that you could gain all kinds of insights about why something works (or fails to work) by putting it on the scope. Also, with a couple of signal generators you can play with Lissajous figures, which is not really useful but kind of fun.

The other thing: in the basement there's a console stereo, vintage 1975, and something has to be done with it. It doesn't work; the woofers are shot and when you turn on the amp, it emits a 60-cycle hum for about two seconds before its circuit breaker trips. That makes me think the problem is in its DC power supply--it sounds like the amp is getting unrectified current--and I'd bet I could fix it if I could get at the thing. As I recall the circuit diagram for the amp is glued to the back cover, even. The old stereo is currently behind 1.3 fucktons of junk (down from 8.37 fucktons at the beginning of the year). Fixing the amp and replacing the woofers--or getting them reconed--would be a big undertaking, but then I'd have a functional record player again, and I could always replace the 8-track player with an MP3 player....

These are the kinds of things I think about.

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