Hacker News Reader

Comment by crote | Hacker News Reader

Most of that complexity isn't needed, though.

Getting 5V out of USB-C is pretty trivial, all the way up to 3A. The vast majority of hobbyist projects run on 5V, and very few of them need more than 15W.

Most of the rest seems to be over-engineering. You can get a ready-made "PD Trigger" board for literally $1 [0], which will allow you to select the desired voltage using jumpers. It even has support for the non-standard (although still common) 12V profile. Or, if you really want to do it using software, grab a $6 one from Adafruit [1] which comes with a tutorial and Arduino library.

If you really want to yak-shave, grab an FUSB302B. They are quite affordable, widely available, and provide easy access to protocol-level PD comms. It's only really needed once you want to implement something like Alternate Modes, though.

[0]: https://aliexpress.com/item/1005003828144045.html

[1]: https://www.adafruit.com/product/5807

View on HN

I'm adding USB to projects just as a power cable but I'm (still) trying to avoid surface-mount.

The only USB connector I've found that is still through-hole is USB Mini-B so I am unfortunately stuck with that.

(I should mention I am building kits for hobbyists who are averse to tackling an SMD component — they make me nervous as well.)

They do exist [0][1][2], but they're not really suitable for hobbyist kits either. Due to the pin density they aren't really any easier to solder than SMD.

If I were to design a hobbyist kit, I'd probably just use a breakout board with the USB-C connector already soldered onto it.

[0]: https://www.lcsc.com/product-detail/USB-Connectors_Jing-Exte...

[1]: https://www.lcsc.com/product-detail/USB-Connectors_XUNPU-TYP...

[2]: https://www.lcsc.com/product-detail/USB-Connectors_Korean-Hr...

Thanks, looking at these 6P connectors, the through-hole mounts ought to make the SMT connectors easy to solder down. I'll pick a few up and try them out on my next PCB project. (Worst case I can pre-solder these to the PCBs in the kits.)

Even hobbyists should be able to handle a fat pitch part like a surface mount micro USB-B. (I’m talking about once they get over the mental block. :) )

With wings and small holes to help with rough alignment, I’d sure rather buy a kit with micro-USB than mini.

Let me be the nth person to say don't avoid surface mount. Temperature controlled soldering irons are cheap now. Once you have one, coarse pitch SMT parts are really just as easy to solder as through hole.

At this point I think I'd rather have a DC jack than mini-B

I think I might even own more USB-A/C to DC cables than I own mini-B cables.

I'm perplexed by the desire to move away from DC jacks as well. Power needs 2 pins. Using a multipin connector knowingly to only use 2 pins is rather confusing.

Personally I would prefer USB-C for everything. I have plugged in the wrong DC adapter (wrong polarity or voltage but the same physical form factor) far too many times and killed too many things. Not to mention all the device-specific DC adapters that have been lost through the ages.

But for a hobbyist device, the currently available USB-C jacks have pins that are too small to solder by hand so I'll settle there. It would be nice if hand-solderable breakout boards were cheaper and more commonly available (the DC trigger boards out there are a great start but typically have to be ordered direct from China)

But for factory-manufactured goods, DC jacks need to die and be replaced with USB-C.

Meanwhile there is no room anywhere for mini-B, micro-B, etc anymore, even on hobbyist devices. I'm not even sure I could even find a mini-B cable in a physical store nearby anymore.

Yeah, that's basically it. I have a drawer of barrel-jack wall warts but they all vary in diameter, polarity, voltage, current... USB is a nice standard 5V source.

Even the confusion about USB-C devices and adapters is nothing compared to the insanity that is DC jacks. At least USB-C will just not work instead of destroy things.

My parents had a D-link DSL modem and Router where both the devices looked pretty much the same (they were stackable), had the same DC jacks, the power adapters looked the same, but were different voltages, which you could tell in white-on-gray 12pt text.

The "problem" with dc jacks is you have to know what voltage something needs, maybe years after your or someone else built it. With usb-c you might have to remember that it needs a power supply with 15V support, but it won't let out the magic smoke if you chose the wrong one.

I've fried a couple things over the years plugging in the wrong power supply (always during a move/reno when multiple things were being replugged) so the ability to have the device negotiate it's own voltage from a standard source that can be reused is a blessing. I still have a collection of random wall worts from the past just in case, but never seem to have the one I need when something dies.

DC barrel plugs aren't best in terms of contact stability, they can rotate and slide and create noises. Something with locking and indexing would be better, which USB-C don't quite qualify but I guess is close enough.

As crote pointed out, you can get THT ones, but this sounds like an XY problem: I would reflect on why you (and the kit targets) avoid SMD, and if that's something you should consider doing.

Out of curiosity, why is SMD avoided?

In my experience (as a self-taught hobbyist), SMD is easier to work with given cheap equipment (an Amazon skillet, some aquatic sand, and a cheap tube of T5 paste).

Don’t forget that you can often through-hole mount cheap readily made module boards like the one above. Often without adding height.

It looks a little hacky, but I may have to succumb, ha ha.

I was hoping to use something like this for my Son's Christmas tree but it needs 33v. For some reason I cannot find ANYTHING to drive the lights on this tree. The old, broken power supply is labeled as 33v @ 800mA (26w) but all the power supplies I can find don't even come close. I tried ordering a custom one from AliExpress and it worked, for about 10 minutes, then it overheated and the lights started flashing.

I would much rather just use a standard USB-C power brick and run it through something like the boards you listed, but they don't seem to support 33v. Any help would be greatly appreciated.

I'm confused by the article; I use USB power delivery with USB-C all the time, and haven't hit the considerations it mentions. Set up a fuse and diode on the power out, set up the CC resistors, choose a footprint in SMT or THT as appropriate.

Reply on news.ycombinator.com