snops
Joined 12 years ago
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Recent submissions
Comment · 7 months ago
Comment · 10 months ago
TFA does directly mention the NPU "Arm-China Zhouyi: 30 TOPS (Dedicated)"
"you cannot simply use standard versions of PyTorch or TensorFlow out of the box. You must use the NeuralONE AI SDK."
Neon is a SIMD instruction set for the CPU, not a separate accelerator. It doesn't need an SDK to use, it's supported by compiler intrinsics and assembly language in any modern ARM compiler.
Comment · 10 months ago
Really neat clean code!
I like the single C file, but Docker if you want all the examples approach, that's really convenient for embedded.
Test coverage looks good as well, be interesting to see the metrics.
This would be quite cool for adding scripting to medical devices, avoiding the need to revalidate the "core" each time you change a feature.
An interesting comparison would be against an embedded WASM bytecode interpreter like https://github.com/bytecodealliance/wasm-micro-runtime, which is still much larger at 56.3K on a Cortex M4F. Maybe WASM is just a more complicated instruction set than the smallest RISCV profile?
Comment · 1 year ago
It would be operating off rectified DC (like an induction hob) or using a SMPS operating at ultrasonic frequencies to deliver a lower DC voltage, you wouldn't get the 50Hz buzz even if there was a transformer.
Comment · 1 year ago
The best part I find about ChargerLab teardowns is identifying all the passive and discrete components.
Western distributors tend to only stock western/japanese brands of these, but they can make up a sizable fraction of the BOM (especially electrolytic capacitors) so knowing who the big players are comfortable with using is very handy. LCSC stock a lot, but its nice to know which suppliers have been proven in use.
Comment · 1 year ago
It can, it just needs the two resistors, which is the cheapest possible thing the standards committee could have asked manufacturers to do.
USB-C gets complicated at the high end, but for basic functionality I think the standards committee did a very good job at making the cheapest way to do it the correct way, e.g. a USB-C to 3.5mm audio adaptor can be entirely passive, it just needs the right resistor in it.
Comment · 1 year ago
I think the most recent surge is due to LLMs, the only way to (easily) apply them is to have some form of code like textual representation of your problem domain so "circuits as code" is the obvious way to wedge them into electronic engineering.
Kicad also makes it easier to make such startups as it has an open file format with several different free viewer tools and lots of content (schematics/footprints). If that ecosystem didn't exist I don't think you would see as many of these startups around, but with that you can launch one of these tools within a initial VC funding
Comment · 1 year ago
The article links to a Linux implementation that does it with off the shelf WiFi hardware. You do need specific features in the hardware/firmware, but there are consumer devices that have that e.g. Atheros AR9280.
https://github.com/seemoo-lab/owl
It currently drops connections to an AP, but the authors of the implementation seem to believe this could be fixed:
> OWL does not allow a concurrent connection to an AP. This means, that when started, the Wi-Fi interface exclusively uses AWDL. To work around this, OWL could create a new monitor interface (instead of making the Wi-Fi interface one) and adjust its channel sequence to include the channel of the AP network.
Comment · 1 year ago
The cable is cooled by a mix of water and glycol, which runs through the cable and also cools the connector pins. Tesla use this in their supercharger cables, as without it the cable would be too heavy.
https://www.cpcworldwide.com/Liquid-Cooling/Electric-Vehicle...
Comment · 1 year ago
Marimo does this for python, by tracking dependencies.
Comment · 1 year ago
This is really well documented with lovely schematics, and the link in the github to the proper "korg style" toggle switches [1] on AliExpress is worth the read.
The code [2] is very nice as well, showing how clean a bare metal Pi Pico project can be.
[1] https://www.aliexpress.com/item/32958319752.html
[2] https://github.com/shmoergh/hog/blob/main/boards/midi2cv/src...
Comment · 2 years ago
Smallest Swissbit do is 512MB, but that's as it's SLC flash so far lower capacity.
https://www.swissbit.com/en/products/product-finder/products...
Looking at pricing, 1GB is only about 25% more in unit quantity.
https://www.mouser.co.uk/ProductDetail/Swissbit/SFSD1024N1AS...
MLC/TLC flash will be 2GB and up, and most consumer cards you can buy.
Comment · 2 years ago
Brushless drone motors suffer from too high a kV (~operating RPM), needing a lot of gear reduction for this kind of application, but I take your point about volume.
Gimbal motors (also in drones) are closer to what is needed, and often come with encoders and centre pass through holes for cables.
Some manufacturers now make larger versions [1] with gearing and a built in motor controller, originally more for robot dogs than robot arms so backlash etc is worse, but the low gear ratio lends itself to cobot type.
For more conventional robot arms (high precision and stiffness) the harmonic drive gearbox patents have expired so there are some [2] of those coming out of china. This offers a really high reduction and very low backlash.
Comment · 2 years ago
Reducing the RAM requirement to 8GB to fit this on my Macbook Air M2 (with room left for other running apps), I get the same figure (66 GB/s) regardless of the number of threads.
If I actually set it to the size of physical memory performance is _much_ lower, as OSX tries to compress the RAM it is using.
Comment · 3 years ago
You can "freeze" micropython modules and have them saved in flash with Micropython, where flash only stores the precompiled bytecode.
If your module contains stored data in the form of an immutable object, like a string or bytes(), it will be read straight out of flash without copying to RAM first.
This needs you to run some code on a desktop computer to perform the freezing though.
https://docs.micropython.org/en/latest/reference/constrained...
They have a "fire containment bag" they can chuck it in should you notice it getting hot or smoking.
https://www.virginatlantic.com/en-US/help/articles/powerbank...