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chrisallick: This looks awesome, I'd love to get one. Question, what's the advantage over something like the ESP32C3 and the like? Just even smaller?

throwaway81523: It's a much less fancy cpu that's very small. No wireless. Lower powered I would expect. But it's an MCU with something like 16KB of flash and 2KB of ram if I remember right. The analog stuff on it is supposed to be pretty good. The Anduril flashlight firmware (toykeeper.net/anduril) is a somewhat popular application that can run on it.

tgsovlerkhgsel: > Lower powered I would expectWith the right software, ESP32 can be incredibly low power. Like "months on 3xAA batteries" for watching a pin with the ultra low power subsystem and then occasionally waking up and making a HTTPS call over WiFi.

tl2do: I'm interested in this too. I've been using STM32 NUCLEO boards, which are cheap and capable, but even the smallest ones are noticeably larger than this. I'd love to see an STM32 version of this project.

rkagerer: I've used earlier Atmel chips, and the ESP32-S3.One big advantage will a far cleaner, simpler instruction set (AVR), that makes it much easier to calculate the exact number of cycles you code will use (handy for applications requiring deterministic timing and for knowing worst-case execution time of interrupt handlers). Atmel also tends to do a better job of their probably documentation.I like the S3, and it's heaps powerful, but I've lost count of how many confirmed errata I've reported to Espressif and the time and steam I lost troubleshooting them in the first place.

george_max: Very nice. I am wondering -- why have a devboard this small?

rolph: [delayed]

polalavik: Why not usb c male?

samhclark: It isn't necessarily smaller. See https://github.com/PegorK/f32

greyface-: Or one of these: https://github.com/AnasMalas/pcb-edge-usb-c

girvo: > If the C3 instruction set is anything like the S3, I'm willing to bet it's not as straightforward.Its not, not really anyway. The Xtensa LX7 in the S3 is very weird, though also quite fun to play with. The C3 is RISC-V

rkagerer: Thanks for correcting me. Are there any good, small "Hello World" examples of RISC-V programming with the C3 you can point me to? I'd love to get a sense of how it compares in practice.

rkagerer: That's it, I'm going back to parallel port cables for everything now.

jasongill: The parallel port (at least in it's later implementations) actually supports DMA - I'm sure that data exfiltration via the parallel port is hard, but probably not impossible...Nothing is safe, unfortunately!

motorducky: That thing is sexxxy. Very nice board, beautiful documentation.

stephen_g: Title is inaccurate, it's really designed to be about the size of a USB-C receptacle , the plug is the other side (in this case the part of the cable that plugs in to this board)

vdcjhhhcfdd: That's not a plug. To be precise, that's the opposite of a plug xD

throwup238: It’s almost certainly impossible on modern systems. The southbridge which allowed DMA to parallel port was absorbed into PCH and slowly stripped of legacy LCP support by chipset and motherboard manufacturers.

ecesena: I dream of an open board like the yubikey nano. This is very nice!

claytongulick: I'll second this.Doing asm on the AVR is beautiful, you can count clock cycles easily and then observe them on the scope.I wrote a bit banging serial interface for an AVR once and had a mystery when I was testing it from a PC just with a basic echo. Every Nth character would be wrong. Was able to figure out a timing problem by counting clock cycles and found the bug in my code.Was cool to see it align with what I was seeing on my oscilloscope.

Lwrless: I recently got my hands on an M5Stack NanoC6 (https://docs.m5stack.com/en/core/M5NanoC6), it's also quite small and I'm pretty happy with it. It has onboard IR and a Grove connector, good enough for IoT projects at home.

sleepydog: https://tomu.im/somu.htmlThis is an stm32l432kc in the form of a yubikey nano.

antoinealb: If you are talking about USB-A Nanos, there is https://tomu.im/, which is very nice and interesting.

d0able: Very cool, but what about the $ to manufacture? Things get exponentially(?) harder the smaller it is, especially for custom boards.

gucci-on-fleek: Looks like it only has 6 discrete components [0], and the pinout on the MCU looks like a standard QFP [1] (and everything else is on larger pads), so I think that you should be able to manufacture this using standard production techniques/manufacturers. But I know hardly anything about hardware, so I may be completely wrong here.[0]: https://github.com/user-attachments/assets/0f7962d5-38e1-4bd...[1]: https://en.wikipedia.org/wiki/Quad_flat_package

FiniteIntegral: It's not that things get more expensive as they get smaller. As long as you're within reasonable tolerances it can be more cost effective. There is very little reason in a consumer-grade product, especially a devboard, to push any major fabs' tolerances. SMD components are grain-sized and you can make traces pretty thin.For example, this project is a 2-layer PCB. Those are bog standard. With this small of a footprint it can be printed on a single surface and cut out. The schematic they posted keeps everything on a single surface for print. This is also an operation any fab can easily perform. If you order from China, even cheaper (even accounting for duty cost + S&H).I'd be more concerned about the MCU and the components rather than the cost of a custom PCB.

_flux: That's now lower power, is it? E.g. RuuviTags can run 3 years or longer while sending sensor data 2.5 times per second, with a single CR2477 (3V 1000mAh). An single AA alkaline battery has 1.5V and 2100-2700 mAh (https://batteryskills.com/aa-battery-comparison-chart/ , somehow this data was difficult to find so I'll add this link :)).Bluetooth is lower energy than WiFi, but in your scenario the energy used for the radio is quite low anyway.

amelius: Does anyone here know the reason why Pcbway stopped accepting credit cards? My colleague asked them but I recall there wasn't a clear answer. It is puzzling why they would make it harder to do business with them from outside China. Jlcpcb doesn't have this problem.

luzionlighting: Miniaturization in electronics is getting impressive. In lighting hardware we see something similar with LED drivers and control systems becoming smaller while handling higher efficiency and thermal management requirements.

pedro_caetano: Question for the people who have used the CH32V003 or more generally WCH, either for hobby or production, what is the current state of documentation and toolchain for these chips? Positive experiences, war stories?

aa-jv: This looks great - how viable would it be to use as a USB Audio class device, perhaps as a synthesizer or effects unit? It'd be simply amazing to be able to add audio/synthesis processing capabilities in such a form factor ..

bArray: It was either PCBWay or JLCPCB, but they had a "review window" where it was possible to make changes or cancel an order. They recently switched this to be an automated review, so there was no opportunity for corrections. It could be that the card companies blacklisted them after people started cancelling orders with their credit cards, because their UI stopped supporting the feature.

benterix: nRF52832 are famous for their low energy usage, it's hard to compete with them. However, ESP32 is much more universal.

benterix: Do you have an example of such a setup handy?

girishso: If it had a female usb c connector at the other end, we could daisy chain those or connect other device on the same port (like mcu in the middle).

Liftyee: Ordered from JLC a few weeks ago, their "review" is still manual. You can select a "confirm production file" option to get a second chance too.

ale42: This is just kind-of low-power. Some microcontrollers (e.g. PICs) can have sleep consumptions measured in nanoamperes. Months to years on a coin cell... just, they would need an external wifi module, which is highly inconvenient.

rgoulter: I've used CH32X035 (which is practically CH32V00x plus USB and some other things) at the hobbyist level (no-frills keyboard PCB designs).The impression I get of WCH and their CH32 line is it ... draws heavy inspiration from STM32.WCH provide English translated datasheets and reference manuals. They're fine.Their own recommended toolchain is a fork of GCC. But as far as I can tell, they haven't shared their changes anywhere. The specifics of the changes they've made are a bit beyond my understanding, though.With the open source distributions of GCC toolchains work just fine. I've built Rust crates as firmware libraries for them.That the CH32X035 is very simple to design for (& low cost) means I'd rather make use of it for hobbyist keyboard PCB designs compared to the RP2040.

Liftyee: Pedantic correction: it's a QFN (quad flat no-leads) package, as it doesn't have any legs. Agreed though, this is well within normal capabilities.

kpcyrd: Running Rust on them worked well for me: https://github.com/kpcyrd/ch32v003-demoI had to put in more effort regarding RAM use and flash size, but I managed to fit a game into the 16kb limit regardless: https://github.com/kpcyrd/game-streetcat2026

proee: Just be aware of dorking around with exposed hardware connected to your $2K MBP. If you end up shorting out your DIY circuit, or have external power supplies connected to your dev board, it's very possible you can fry your laptop.Best practice is to have a completely opto-isolated USB connection between your dev system and test hardware. You can buy a USB opto-isolated system for like $100 that will tell you downstream currents and isolate your hardware.

_flux: Actually I've read claims that ESP32 C6s are pretty decent battery-consumption-wise. So much so that I bought a few, hoping to make at least a doorbell out of it. Alas I don't have a device to measure microampers, so I guess I'll just see how long they're fare..

bxbdbehdbdb: I have to second this. Multiple Mainboards in my company were fried before mandatory opt isolation of USB fixed the issue

tgsovlerkhgsel: No, it was an undocumented one-off using a random cheap devboard from Aliexpress (i.e. not some specifically optimized circuit!), built (IIRC) using the Arduino IDE - aside from spending the time to find and configure the low power mode properly, this was done in the dumbest, most naive way possible, and still worked.

BenjiWiebe: You can use ohms law - let it draw power through a 10k resistor, and put your multimeter across the resistor. Every .01 volt is 1 uA. This also means that if you're powering it with 3.3v and it browns out at 3.0v, you'll only be able to draw 30uA before browning out.You can use a different resistor according to the power draw and how sensitive your volt meter is.You'll probably need to power it up with the resistor shorted, and only remove the short once it's in sleep mode, to measure the current.