Learning electronics: Release the Magic Blue Smoke

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Learning electronics: Release the Magic Blue Smoke

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Zuph: Jul 24, 2003; Zupht0r 6000 Turbo Type-R

Sagebrush posted:

istr reading somewhere that all the electrons moving through every manmade electrical circuit on Earth have a total mass of like 3kg.

I don't think that helps in your calculation at all, it's just a neat factoid

Similar neat factoid: When you charge a battery, it gets heavier. Same when you compress a spring.

# ¿ Sep 20, 2018 16:52

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# ¿ May 22, 2024 15:09

Zuph: Jul 24, 2003; Zupht0r 6000 Turbo Type-R

meatpotato posted:

I could use some advice on choosing a super cheap microcontroller for a small low-budget project that hopefully results in manufacturing a few thousand units. Low cost is probably the #1 driver in this design.

I looked at Octopart and the cheapest 32-bit ARM Cortex M0 (what I've used and already know) is about $0.50-60 in a 1,000 minimum order quantity. In comparison, the cheapest 8-bit micros (PIC, SiLabs, ATtiny AVR, STM-8, etc.) are about $0.35-$0.45.

The minimum requirements are a built-in oscillator, a counter, 14+ GPIOs, and a few hundred bytes of RAM and flash. The rest of the design can be adjusted to match. The program it needs to run is dead simple --just basic math and driving a 4-digit 7-segment display.

Am I going to give myself a headache trying to target these 8-bit chips, or are the toolchains and debug/flash tool support still considered ok? I'm not necessarily asking "what chip should I use", but "is it worth the struggle of using any non-ARM uC in tyool 2018?"

Thanks

Jay Carlson has probably the best overview of cheap microcontrollers that has ever existed: https://jaycarlson.net/microcontrollers/

I'm partial to the Atmel tools myself, and you've got a lot of options in that area. If you're really opinionated about open-source and/or Linux-compatible toolchains, ARM is probably the winner.

# ¿ Sep 24, 2018 14:14

Zuph: Jul 24, 2003; Zupht0r 6000 Turbo Type-R

Shame Boy posted:

I'm designing yet another high voltage power supply, and I want its output to be adjusted digitally for various reasons. It's based on an older one that I made which compares a feedback voltage to a reference to get an error value, and uses that to close the feedback loop via a PWM'd transistor on the input. The old one works great as-is.

My idea to make it digitally adjustable is to vary the reference voltage. Can I just use a DAC for that? Are DAC's ok with outputting a constant voltage for a long time, or are they only for outputting signals? My other idea was to use a digital potentiometer as a voltage divider, but I'm not really sure about the stability as most of them are clearly meant to be used as volume adjustment chips for handheld electronics, where precision and stability aren't super important...

I've done exactly this on a low voltage DC SMPS. I'm using the digipot method, and I did a lot of simulation beforehand to make sure the power supply was stable throughout the expected voltage and load range. I've got some voltage feedback, so I'm using a pretty cheap digipot and just adjusting on the fly to get close to the output I want. Works really well so far!

# ¿ Aug 14, 2019 18:19

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