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Comment by krasin | Hacker News Reader

I am currently (as a hobby-style activity) learning guts of the USB Power Delivery standard and found an incredible (and fully open-source) tool: USB-C explorer, https://www.tindie.com/products/reclaimerlabs/usb-c-explorer...

Basically, you attach the board to any USB port and it will show capabilities (voltage and amperage) on a tiny OLED display. And since the firmware is open-source, it's possible to play around and test a lot of what-ifs: https://github.com/ReclaimerLabs/USB-C-Explorer

I am not engaged with the project other than a very happy user.

In other news, the latest USB PD spec allows to pass up to 48V@5A=240W power.

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It may be also be possible to interact with the PD negotiation protocol directly and pretend to be a device / power supply with Luna from croudsupply once released

https://www.crowdsupply.com/great-scott-gadgets/luna

It looks cool but I haven't got one to mess with yet

That's an awesome device, and I want one, but it also passed into my head: Shouldn't I be able to get this information from my laptop? I would expect that there's some way to probe the USB-C chip to find out what power mode it is in and what power modes it could select. I'd love to see that as a tutorial.

I have a poor understanding of electrical engineering so I am not sure this would actually work. But I've wondered if one could make a fairly cheap gadget for turning a decent USB-PD supply into a somewhat useful hobbyist variable voltage DC power supply.

Especially with USB-PD 3.1 which has an adjustable voltage supply mode [1] so you are not constrained to only a handful of power profiles. I think in theory you could offer 5V, 9V, and 15-48V.

It would be cool because it would be much easier to carry (keep in your backpack) and I imagine cheaper than a benchtop power supply so long as you have access to a capable USB-C charger. But I'm not sure what you'd be missing out on versus a proper benchtop.

[1] https://www.usb.org/usb-charger-pd

You might be better off getting a fixed power profile from the brick and regulating down to your desired voltage separately. While it's possible the brick will be well regulated, it's likely to have some noise and output voltage variability. Even for a hobbyist, the DC supply should be clean and well regulated, or you might be stuck debugging your hobby design only to realize it was a power issue all along.

A small board/box with a DC to DC regulator, knob, and display, could still be quite a bit smaller than a big bench supply, and provide reasonable performance. USB-C in (at a fixed power profile) to an output from a variable buck supply, for example.

Like Op, I also have been tinkering with USB-C PD and found another hobbyist tool on Tindie that does exactly like you describe! You can specify the voltage and current needed, and it'll then make sure you get that power from a compatible charger.

This is the one I got a while ago it and it works great: https://www.tindie.com/products/clarahobbs/pd-buddy-sink/ though there's several other options out there

Oh that’s awesome. Thanks for sharing.

maybe something like this?

https://eclecti.cc/hardware/tiny-usb-type-c-adjustable-power...

That's pretty cool, and I've often wanted such a thing, but $80 is steep. How much of that detection ability would you be able to get in software on a laptop with a USB-C port?

This kind of information is usually deep inside EC (embedded controller) and what they expose to the host system is limited. So, maybe it's possible, but I am not aware of a practical option.

Update: it seems that Linux gives some stats about it: https://askubuntu.com/questions/1351186/how-to-debug-usb-c-p...

This looks fantastic. Does anyone know of an opposite tool? One that identifies as a source and works out the demands of a sink?

The price is fine, and even just this one would save me loads of debugging efforts at home.

The opposite tool exists, it's awesome (on paper, anyway), but I could not afford it ($1200). Meet Acroname USBHub3c Pro: https://acroname.com/store/programmable-industrial-power-del...

I use this device for debugging, it's invaluable and cheap:

https://www.jeffgeerling.com/blog/2017/review-satechi-usb-ty...

This is awesome, thank you

Man, I wish there was a program on linux/mac/windows that would show this. (I sell USB-C cables, and like to verify what the cables compatibility is before claiming it can do xyz.)

I am loving usb-c and it's great to see it's increasing in power delivery capability. 240W in a tiny, cheap connector is amazing. As a hobby I am currently upgrading all my old/favorite electronics to usb-c:

- Upgrading a 2009 Apple wireless keyboard to li-ion plus usb-c charging. A 14500 li-ion cell is 3.7C, and exactly the same size as a AA cell. You can get charging/protection circuits[1] and voltage regulators[2] for nothing online.

- Upgrading mice, headphones, etc from micro-usb to usb-c. Usually I solder in a usb-c connector upside down in place of micro-usb, add the correct resistors (there are CC or charge configuration pins). If you don't need data, you want these connectors with only the required pins and not more[3] or breakout connectors if you have space[4]. If anyone knows a breakout connector that has CC resistors installed I'd love to buy it. Or for gluing in place instead of soldering, this connector[5] is the only one I have found of any type with the correct CC resistors already installed.

- Using usb-c for powering small prototype things instead of using a benchtop power supply. You can get power modules configured to one voltage[6], or adjustable ones[7]

- Fixing janky usb-c powered electronics that only work with a usb a-c cable. Usually they are missing charge configuration resistors to get 5V. For 5V up to 3.0A, you can use simply using these resistors instead of usb PD. Usually you have to replace the connector with one that exposes the CC pins.

For all of above, this device[8] is invaluable for troubleshooting although this one looks like it has more capabilities similar to the usb-c explorer[9]. And might as well get a usb-c soldering iron too[10]. And this GaN power brick which is tiny[11]. It's enough for an intel macbook under light loads.

[1] https://www.aliexpress.com/item/1005002953903622.html

[2] https://www.aliexpress.com/item/32813195533.html

[3] https://www.aliexpress.com/item/32966491026.html

[4] https://www.aliexpress.com/item/1005001335550637.html

[5] https://www.aliexpress.com/item/1005002449606066.html

[6] https://www.aliexpress.com/item/1005001668143510.html

[7] https://www.aliexpress.com/item/1005002196188312.html

[8] https://www.jeffgeerling.com/blog/2017/review-satechi-usb-ty...

[9] https://www.aliexpress.com/item/32968303350.html

[10] https://pine64.com/product/pinecil-smart-mini-portable-solde...

[11] https://us.anker.com/pages/ankernanoii

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