[Tony] built a high-efficiency power supply for Nixie tube projects. But that’s not what this post is about, really.
As you read through [Tony]’s extremely detailed post on Hackaday.io, you’ll be reading through an object lesson in electronic design that covers the entire process, from the initial concept – a really nice, reliable 170 V power supply for Nixie tubes – right through to getting the board manufactured and setting up a Tindie store to sell them.
[Tony] saw the need for a solid, well-made high-voltage supply, so it delved into data sheets and found a design that would work – as he points out, no need to reinvent the wheel. He built and tested a prototype, made a few tweaks, then took PCBWay up on their offer to stuff 10 boards for a mere $88. There were some gotchas to work around, but he got enough units to test before deciding to ramp up to production.
Things got interesting there; ordering full reels of parts like flyback transformers turned out to be really important and not that easy, and the ongoing trade war between China and the US resulted in unexpected cost increases. But FedEx snafus notwithstanding, the process of getting a 200-unit production run built and shipped seemed remarkably easy. [Tony] even details his pricing and marketing strategy for the boards, which are available on Tindie and eBay.
We learned a ton from this project, not least being how hard it is for the little guy to make a buck in this space. And still, [Tony]’s excellent documentation makes the process seem approachable enough to be attractive, if only we had a decent idea for a widget.
My sympathies go to the author. I’ve produced several short run (low production) boards and can relate to every issue that was mentioned. Except I have the advantage of using a local (USA) assembly house and this reduces some of the head banging issues.
For small runs like the 200 board build described in the article, China assembly is probably not a good choice for lowering costs. For reference, I pay about 10 cents per component for local SMT assembly. Plus my vendor picks up and delivers for free (they are less than 20 miles away).
So for those of you that are considering a short production run, check your local area for assembly vendors and get quotes before making the leap to offshore production. You may find that the true costs are similar and staying local should result in less head banging.
If I recall correctly, the OP was based in Singapore. So, the Chinese fab houses are (more or less) local to him.
“The power supply is compliant with IPC-2221B and IPC-9592.”
The requirements per IPC2221 are not representative of safety-related spacings; that is, this particular IPC standard is for functional and manufacturability. And the last time I looked at IPC9592 (used mostly for functional and reliability guidelines) , the referenced safety standards had been obsolete for almost ten years. IPC9592 then goes on to say to ignore these spacing minimums and then references a (deprecated) ITE safety standard.
Seems to be a decent unit, but should not depend on the power supply to provide adequate separation or insulation or galvanic isolation from hazardous voltage to dogs or cats (but no concerns about humans, as they are interchangeable and disposable).
> At the current rate of 4 boards per week, it would take 34 weeks (9 months) just to get my money back. At this breaking-even point I would have sold 137 power supplies.
Might want to adjust that calculation now though…
Nice writeup. The only thing i dont like is the fact that the mounting holes carry power. Even the HT one. Makes mounting and not touching that corner a challenge during experimentation. For the next version I suggest isolating all the mounting holes and keep the exposed HT side to a minimum.
Indeed, it´s an horrendous choice that negates any attempt to make the board safer. Nobody would ever expect the screws to carry HV and this choice makes mounting the board on a metal plate impossible. Terminal blocks exist for a reason !
This is a perfect example of common-sense mechanical engineering (or safety) being an afterthought on many DIY boards. I had to do a double take at the picture, and sure enough. Wow. 170V….I wish the editorial staff would take a harder look at safety and what they tacitly promote. This design requires insulated standoffs to be safe. Why?
awesome post.
i got my chuckle out of “In order to work with 0603 components and the tiny 0.5mm pitch regulator you absolutely need a microscope”. me, 30, still soldering 0.5mm pitch and 0402s without optical crutches here. did my training with a microscope, but the things are just too expensive. the good ones at least.
Offshore manufacturing is a bad idea, if you stick to the proper meaning of this word which is “manufacturing outside any shore” or “manufacturing on a boat”.
It is still common practice for cheap electronics in Europe to be imported as parts from China and to be manufactured on the boat on the way to the destination.
Humidity and salt in the air affect the final product quality and this is why we see TVs, radios, clocks, multimedia players, bad hard disks such as cheap 2 TBytes Seagates failing after a few months.