> blue-pill STM boards Those are useless for practical application. 64 KB of flash and 20 KB of RAM on a stereotypical STM32F103 (edited to add weasel words:

> blue-pill STM boards Those are useless for practical application. 64 KB of flash and 20 KB of RAM on a stereotypical STM32F103 (edited to add weasel words: that's what a blue pill is, correct? I don't actually use them.) Remember these are not PCs where you slap in a bigger SSD or another stick of DRAM. I have a F767 dev board on my desk. Kind of the same family, 'F' series anyway, and it has 2M flash and I believe 768K of SRAM. My latest simple application build (built while posting this) ended up 228744 bytes of flash and 142119 of sram. What kills modern microcontroller storage is every thread has its own fixed size stack so 1K there, 16K there, pretty soon you've got a lot of RAM in use if you go thread-happy, and on the flash side like every civilized embedded device it has MCUboot so 2M sounds like a lot until you partition it into two bootable partitions for OTA upgrades and MCUboot itself takes 64K or 128K or whatever, and there's a big fat (not FAT32 lol) partition for non-volatile config storage. It doesn't matter what RTOS you're using they all seem to be about the same size in the end, FreeRTOS, Mbed, or Zephyr. Another point worth making is peripherals, I'm pretty sure the F103 doesn't even HAVE the capability to connect ethernet whereas I'm doing OTA upgrades using wired ethernet using the F767. Note that for decades now, I guess, its been possible to build a washing machine or a lithography machine as an arduino shield or raspi shield, but nobody does that. The part that would not be a boon would be FCC certification, UL certification, and whatever other safety certifications a product requires. With respect to washing machines as a homeowner I have had to do some repair work on multiple dishwashers and value engineering is the rule, if it corrodes out in five years needing replacement from the point of view of the mfgr that's a "feature" not a bug. So I've never seen a conformally coated washing machine PCB although I'm sure they exist if you don't buy big-box store garbage. Let me remember... Some piece of trash from Sears from 15 years ago used to ship with mosfets having too small of a heatsink and a voltage rating about 5 volts higher than line voltage and an underpowered pump so the user was encouraged to use the water heating mode in operation to keep the water as hot as possible for the anemic pump resulting in the mosfet blowing out every year or so, replaced the PCB under guarantee about three times and tossed that POS. Got a Bosch from horrible depot and that one has a pump that somehow is anemic AND sounds like a screaming jet engine bearing after a year of use, on the third pump now and just ignore the incredible noise. I'm told for eco reasons the new greenwashing dishwashers use 10% less water but don't work at all so you have to run them three times to clean the dishes resulting in 3x the wear and tear (good for mfgrs) and roughly 170% increase in environmental damage over a non-greenwashing dishwasher.