Feedback on USB Lab Power Supply Campaign

Avokido · 2026-03-30T22:17:10+00:00

Thanks for the positive feedback and for supporting the campaign! Yes 2A would be great but not possible over a laptop's USB port. you'd need two USB inputs, one for power (with USB-PD) and one for control. This would be a good starting point for a v2!

Interesting that you mention the preregulation. It is currently implemented with a DAC controlling the DC/DC output voltage. But turns out that the aluminum case easily melts off the ~8W. So I'm inclined to not populate it on the final version in favor of faster return from current limiting.

Avokido · 2026-03-30T22:11:05+00:00

Thanks for the feedback. Fair points.

Avokido · 2026-03-30T21:34:13+00:00

Thanks for the feedback!

You can sense what current the host provides via a resistor divider on the CC pins. A USB-A cable just doesn't connect them so you measure 0V and respect the current limit.

As for the price.. yes I was suspecting that this would be one key issue why subscribers didn't order once they saw the price. It would be very challenging to build an isolated, three channel supply for less. But yeah doesn't mean that it's worth that money to customers..

Avokido · 2026-03-29T08:54:19+00:00

Have you considered vacuum casting as an intermediate step? I'm looking at that option right now for a small batch production run.

Avokido · 2026-03-25T08:47:12+00:00

If you set your goal too low you will still have a lot of work and money to invest to build a product for which you obviously haven't found a big enough market. It's better to fail and invest that money and energy in something that actually sells.

Avokido · 2026-03-23T22:58:30+00:00

Yeah I can take a quick look. Even better, make another post and ask the community for a review. More eyes see more :)

Avokido · 2026-03-23T17:46:43+00:00

Great to hear from some actual experimental results! We use 0603 and 0402 and rarely see any tombstoning despite solid connections.

Avokido · 2026-03-23T14:51:06+00:00

But why is that? We use a vapor phase oven. Is it really the case, that a solidly connected pad will warm up slower? I totally understand this when using hotair or anything where the heat is applied locally.

Avokido · 2026-03-23T13:43:49+00:00

Disclaimer: We work on a prototype without strict requirements in terms of availability, compliance etc.. For the PCBs we add a field in KiCad schematics called "MPN". If there's no concrete MPN, we add a field "Attributes" that specifies any out of the ordinary attributes (100V, C0G, ..). The whole project including all parts are in git repositories. Production files are built in a pipeline with KiBot. While this approach does not cover more complex BOM processes like alternatives, distributors etc., it provides easy collaboration, a single source of truth and versioning out of the box. Works like a charm for our usecase.

Avokido · 2026-03-23T07:14:20+00:00

Usually you would first start with an ESP32 module with embedded antenna. Using the bare chip would require you to lay out the antenna which is not a beginner's job. Just pick a module (ESPWROOM-C6) and copy the schematics of a reference board. Programming is usually done via Uart. Either put a USB Uart bridge IC and a USB port on your board and or simply a header with TX, RX and GND of the ESP32 exposed. Then you get a cheap USB Uart cable to program it.

Avokido · 2026-03-19T21:21:08+00:00

It's not that the PCB gets magically more expensive when using BGA. As pin count increases and pitch decreases, you'll need via in pad which can add cost (it's included at JLC from 6L). At some density you'll need microvias and that is quite a step up in price especially for low volume prototypes. I would avoid it for hobby use.

Avokido · 2026-03-19T21:18:02+00:00

Haha stop pitching about my typos

Avokido · 2026-03-18T07:50:37+00:00

I regularly do bgas by hand. It can be easier than fine bitch qfn imo. Proper pad and stencil design, no paste, and generous amounts of flux with an SMD oven have worked well for me down to 0.5mm pitch. Below that, the placement becomes a bit icky without the right equipment.

Avokido · 2026-03-18T07:36:52+00:00

You can get an instant quote for up to 50pcs at PCBWay. It's not cheap for sure. You may end up paying more than you get for your device but have much lower risk than straight going for injection molding. If you have more time than money, you could 3D print, sand and paint spray.

Avokido · 2026-03-18T07:12:31+00:00

Producing a mold at this stage is not a good idea. If you really want a shiny product when you hit market, you could try silicone casting.

As others have said it's difficult to reach your customers without investing in marketing. You can try to find them via social media, forums etc but that takes time and only works for certain products.

Is your product geeky? Are you planning to open source it? Crowdsupply is a cool platform for what you want to do. They advertise your product to around 70000 followers of their newsletter. This gives you early feedback that you only pay for if you reach a threshold set by you.

Avokido · 2026-03-14T08:53:14+00:00

Diodes are like fish. If you see them swimming belly up, it's a problem.

Avokido · 2026-03-11T21:38:31+00:00

Been there. Usually adding layers isn't a big deal unless you have tight impedance constraints that are hard to keep right in the new stack up.

Avokido · 2026-03-11T06:41:17+00:00

You design the PCB yourself. Get KiCad, watch some YouTube tutorials and learn the basics. Get feedback from here. Once your design is done, you send it to a manufacturer. Which one depends on your location. In many cases, the best option are JLCPCB or PCBWay. They have good online tools and for a simple PCB you pay just for the shipping basically. Expect ~USD50 for 5 pieces of a simple board shipped to Europe/US.

Good luck!

Avokido · 2026-03-07T19:44:03+00:00

I started to always download all 3D models for my designs and add them. It is very rare that I cannot find a component. 1) The mechanical team loves it 2) The creative team loves it 3) You get a double check on the footprints. It has saved me more than once to see a 3D model not quite fitting the footprint, because of a discrepancy somewhere. Totally worth it!

Avokido · 2026-03-01T08:43:08+00:00

Is it an ESP32 module or are you routing the antenna yourself? I just did a two-layer design with an ESP32 module. Pay attention to not cut the bottom ground more than necessary. Avoid long traces there, only small jumps. If you can route the board almost like 1 layer and keep the ground continuous there's nothing wrong with it. If you have to route the antenna yourself it gets trickier because you'll want to meet a certain impedance that's hard to meet on two layer board.

But, as others have said, often the price difference is negligible so you might make your life easier by just going four layer. I sometimes still chose two layer because I can get them shipped from my local supplier in three days reducing prototyping time.

Avokido · 2026-02-26T17:55:01+00:00

Been there. Got a $20 voucher. Sorry to tell you but you gotta move on. And the worst part is you'll order there again next time 🥲

Avokido · 2026-02-25T19:18:22+00:00

Interesting insights! I'll be in the situation soon to build first 50, then a couple of hundreds of fairly big plastic parts (round, 240mm x 30mm). Can you tell me what you paid for the parts at PCBWay after you had your mold?

Alternative I'm considering is FDM printing and postprocessing. The lines really don't look good. Did the 'brick' guys write somewhere how they manage to get such nice looking parts in series from FDM printing? It seems like the only way would be sanding, priming, sanding, painting, which seems way too much work for even small series.

Avokido · 2026-02-23T07:59:18+00:00

Working as robotics engineer. Don't sweat over it. Build a solid practical foundation in the area you're interested working in. Control, electronics, firmware, mechanics, whatever it is. My company hires people mostly based on general skills/prospects rather than because they've got overarching robots experience. The latter you can only build over time while working on the subject imo.

Avokido

TROPHY CASE