81–90 of 106 posts
It seems awesome, but I'm having a problem with figuring out how can a "normal" person use it. How would YOU use it, reader of this comment?
A silly question (from a non-HW guy). Why are digital bathroom scales so coarse? Some have a weight resolution of +/- 500 grams. Would a better microcontroller make a weight faster or more presise? I guess this TI micro controller is overkill for a bathroom scale.
Computing power is crazy cheap and does not help. The perceived slowness is because the taken measurements are averaged over second or so. When you step on the scale your weight shifts around and that affects the measurement by far more than half a kg. Averaging gives you better accuracy and more confidence in the result but it doesn't improve the measurement precision. The scale precision comes from calibration of t…
Ofc there's auto-zero on start involved, but translated to a people bathroom scale that'd be "comfortably better than +-100g".
A precise bathroom scale just would want a bit more effort on drift prevention as a sample mass at this scale is rather unwieldy, and critically it'd need a toe-operated button to select that you've finished climbing onto the scale, upon which it starts averaging the load to progressively improve the weight measurement accuracy. I'd expect using a bounce-height-freefall-duration based length of timing uncertainty at the start and end of the averaging period to allow proper Bayesian uncertainty quantification of the shown result, say by displaying both the 10th and the 90th percentile on the display which grow closer as you wait while standing on it.
With some cleverness a compact calibration mass might be usable to calibrate absolute scale, transferring up to the "people" range using just a random assortment of stuff that fits on the platform, totalling around 10kg.
Because building the scale to be linear in response good enough for 20k count of resolution is pretty straight-forward.
Earlier quoted context omitted.
Rust compiles to bare metal (assembly aka machine instruction code), just like C does.
Bare metal refers to not using an rtos. I know that sounds weird but it is an industry convention. It does not refer to the language.
Earlier quoted context omitted.
Rust compiles to bare metal (assembly aka machine instruction code), just like C does.
In Embedded, it's usually agreed that "Bare Metal" means using no OS, not meaning using low level languages.
Yes, I should have said binary opcodes instead of assembly. I just assumed anyone discussing embedded systems would know they are practically interchangeable.
Earlier quoted context omitted.
I used to have a bathroom scale with a single strain gauge that was accurate. Accurate, as in weigh yourself, pick up a 1lb object, weigh yourself again and see an extra pound. That scale had a "lifetime" nonreplaceable battery in it and after 20 years or so, gave up the ghost. Every scale I've tried since is wildly inaccurate, and they do have brains and they fake it. Step on, get a random weight within a 5lb range…
> Accurate, as in weigh yourself, pick up a 1lb object, weigh yourself again and see an extra pound. That's resolution (or dynamic range), not accuracy. The scales could be 10lbs off of your weight and still do this.
Could you put a few thousand of these on a PCB and have a super duper tiny compute cluster?
If you had 1024 of these, you'd have a grand total of 1 MiB of RAM. You won't be compute clustering much with 1 MiB of RAM.
Earlier quoted context omitted.
In Embedded, it's usually agreed that "Bare Metal" means using no OS, not meaning using low level languages.
Either you do not understand what assembly is, or you are being pedantic about the very thin abstraction between assembly and opcodes. Just in case you didn't know, assembly is a convenient way to read the binary opcodes that the cou uses to move data between registers and execute logic. Yes, I should have said binary opcodes instead of assembly. I just assumed anyone discussing embedded systems would know they are p…
It seems awesome, but I'm having a problem with figuring out how can a "normal" person use it. How would YOU use it, reader of this comment?
Earlier quoted context omitted.
Computing power is crazy cheap and does not help. The perceived slowness is because the taken measurements are averaged over second or so. When you step on the scale your weight shifts around and that affects the measurement by far more than half a kg. Averaging gives you better accuracy and more confidence in the result but it doesn't improve the measurement precision. The scale precision comes from calibration of t…
My fine spice recipe writing scale (20g max, 20k count) consistently over years of me having it keeps it's magnitude calibration of the 10g reference to a single digit count, i.e., comfortably within +-0.1%. Ofc there's auto-zero on start involved, but translated to a people bathroom scale that'd be "comfortably better than +-100g". A precise bathroom scale just would want a bit more effort on drift prevention as a s…