This isn't really supposed to be a holiday for me; there's all manner of stuff I should be doing, some of it for actual clients, but...
Well...
My brain just isn't in working order. Can't do anything that requires thinking, or focus, etc.
Also, I'm not feeling altogether well, so anything involving major physical exertion is out. Ergo, no yard work.
So do I turn on the telly? I do not. I don't actually have a telly, as such, though one of these computers has a tuner card installed, so watching the teevee is not entirely out of the question.
No, I try to do something at least a little bit productive with part of the day, as long as it doesn't get complicated. In this case, solder paste was involved.
I think I'd mentioned something about ordering thermocouples from Amazon, right? They arrived just about the time I was ready for them.
Yes, that's my proof-of-concept, 4-channel thermocouple-to-USB board, slightly under business-card size. I assembled it and implemented the 4-channel version of the measurement task today. It works, at least as far as rudimentary testing can determine (all four channels read room temperature; if I pinch one, it reads skin temperature; if I hit one with a flame, it reads around 800°C and the other three don't change).
Got the connectors, a somewhat upmarket analog MUX (low ON resistance, but mainly very high isolation), a thermocouple-to-SPI chip, an outrageously overkill $4 MCU (think: massively overclocked VAX), and the usual odds and ends, including a second MCU (handling the multi-function button) that I'll have to replace eventually because I didn't test its firmware well enough before soldering it down.
The readings aren't hooked up to SCPI commands yet, though. Determining exactly what the commands should be (read a channel, read specified channels, set measurement rate, ...?) and implementing them gets into needing-to-think territory, and my brain's not up to it.
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