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Discussion (51 Comments)Read Original on HackerNews
The 1KB of SRAM is admittedly very tight (even WCH's 10-cent RISC-V parts usually give you 2KB), so you are strictly in bare-metal, carefully-managing-your-stack territory.
Not worth changing the design now...
The scale precision comes from calibration of the measuring mechanism done on factory line at certain weights. If your specific body weight is far from the weights used in calibration, or too much time passed, then the calibration doesn't help much.
A better microcontroller doesn't help at all. Even a cheapest uC from decades ago is good enough. Better ADC and gauge sensor would help, but even more important is good analog engineering to produce self-correcting circuits with decent noise rejection.
In general this category of products is more for tracking changes in your body weight than getting the precise absolute value. And the body weight changes a lot just from hydration level, so the ±.5kg tolerance is considered good enough.
I guess the overall finickiness of that can't be instantly improved by a better microcontroller alone? They drift and have linearlity issues and show temperature dependancy and all that.
Precise body weight measurement at bathrooms is also probably not that important, 500 grams is one full bottle of soda/water; body weights can easily change that much within a single day.
I would suspect that the "real" reason is combination of both. 100-500g can be a "good" compromise for cheap bathroom scales.
This is why highly accurate scales usually have very low max weights.
Decreasing resolution hides all of those.
For majority of use cases nowadays it's much easier to use a programmable chip than invent a complex device using discrete analog electronic parts.
I have no grasp of even the magnitude of the price for something like this.
Can get under 10 cents each for cheap minimalistic CPUs in high numbers.
1-99 $0.720
100-249 $0.48925
0-999 $0.378
1,000+ $0.251
In terms of projects that I would be inclined to try that are uniquely enabled by this, my mind goes towards wearables. It's small enough to be hidden in seams of fabric. If you wanted to have a bunch of temperature sensors all over your body, or have a complex arrangement of dimmable LEDs woven into clothing, each string going to its own controller hidden close by and communicating with a central controller, or maybe measure your skin conductivity all over your body or something, this is a great piece of tech to do that with style. You still need to run power and data wires everywhere (no RF on this chip), but flexible wires are a very solvable problem.
The applications required only I2C to communicate with a bunch of other integrated circuits and a few general-purpose pins.
An example of an application was a kind of hardware video converter, which received video input from a camera and then sent it wirelessly or on cables, where the MCU configured and reconfigured everything on the board, after reset or when certain buttons were pressed, and the configuration for some things, like a HDMI transmitter, was complicated, requiring the reading and the writing of many internal registers via I2C, so a MCU was really needed.
There are many types of complex integrated circuits that need to be configured with values written in internal registers to be usable, so, even if just for the initial configuration after reset, you need some small MCU that can write the registers via I2C or SPI. For this, the smaller the MCU is, so it will not take space on the PCB just for booting the other ICs, the better.
I made and tested it but didn’t care enough to continue.
With tiny mcu like this one, I think it would be possible to add a bodge inside that would turn on recording automatically after single press of button. The MCU needs to be really tiny to fit inside camera.
Applications
• Battery charging and management
• Power supplies and power delivery
• Personal electronics
• Building security and fire safety
• Connected peripherals and printers
• Grid infrastructure
• Smart metering
• Communication modules
• Medical and healthcare
• Lighting
But like *really* tiny.
1KB is surely enough to store synthesizer patches. Several, probably.
They'd be done already if they bought up or licensed Analogue though.
On top of all this, latency for anything is gonna be abysmal because the cores are so slow...
I honestly don't see an application where this is even close to desirable.
Would be fun, tough, to have a 10-stack of PCBs with 10 by 10 CPUs each for a thousand cores (=> ~4W power @1.8V).
The ADC is really nice though, 1.5 MSPS is really good for such a small/low powered thing (fills the whole RAM in under half a millisecond).
I could only imagine the bringup fun for thousands of them. :P