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Posted by chipweinberger 2 days ago

What I learned selling 2,500 MIDI recorders: Hardware is not so hard(chipweinberger.com)
550 points | 256 commentspage 5
yanslookup 2 days ago|
This is not a criticism but I am curious about what the trade offs are in terms of cost/bom etc of using usb-c. I found it surprising that that wasn't a given in 2026,curious where it hasn't caught up as an option.
Kirby64 2 days ago|
Assuming this is just standard 2.0 speeds, it should be nothing. It adds a slightly more expensive connector and 2 resistors… and that’s it.
crote 20 hours ago|||
It is likely to be 1.1 speeds, and considering that USB-B connectors are chunky and dying out it is likely going to be cheaper to go for USB-C.

USB-C connectors from well-known brands start at less than $0.20, USB-B ones are $0.30. Same story for the low-end: C can be found for as little as $0.011, B starts at $0.05. Resistors are basically free - about a cent a piece if you splurge, more like $0.0007 if you really push it.

With the EU practically mandating USB-C on all portable electronics, the market is rapidly shifting towards it being the default for all 5V-powered gear: either you ship a cable/brick with it, or you give it USB-C. Even with a premium connector it is quite obvious which option is cheaper, so even bargain-bin gear is incentivized to adopt USB-C, which in turn pushes the connector manufacturers to develop dirt-cheap USB-C options.

Kirby64 20 hours ago||
> It is likely to be 1.1 speeds, and considering that USB-B connectors are chunky and dying out it is likely going to be cheaper to go for USB-C.

USB 2.0 is a superset of 1.1 spec and considered inclusive of 1.1 speeds. I said 2.0 speeds specifically because Type C does not even recognize “USB 1.1” as a speed, and when you go to 3.0+ you start to put other constraints on routing and most importantly requirements on the cable (it needs to be emarked if it supports super speed).

The rest of your comment, totally agree. Especially with EU mandating power be USB-C if possible, which this easily could be.

chipweinberger 1 day ago||||
If you consume power over USB-C, 2 resistor are enough.

But for providing power over USB-C, you generally need a dedicated IC to handle VBUS switching. It wasn't worth it.

Also, once you ship a consumer product with a USB port on it, you'll realize a lot of people really don't understand how USB works, and USB-C doubly so. Square holes for square pegs goes a long way.

Kirby64 1 day ago||
Sure, but your power input should be a USB-C. No reason to use the clunky USB-B for that. Labeling as Power In and leaving a regular USB A for the output seems fine to me. Given that most older keyboards use USB-B for their input, A is a perfectly fine solution and solves the “input vs output”.
crote 20 hours ago||
OP mentioned in another comment that a decent chunk of users is elderly, and C-to-B cables (albeit rare) do exist, so confusion isn't impossible.

I personally really don't like it in a world where everyone has USB-C power bricks readily available and USB-B cables are dying out, but considering the user base it is not an entirely unreasonable design decision - for now.

bloudermilk 2 days ago|||
These are the hardest cuts to make in design, being so incremental, but they add up!
Max-q 1 day ago||
The article doesn’t mention certification, which is expensive and demanding, but required for any product containing a radio to be legal to sell.
brookst 2 days ago||
Great write up!

Why custom MIDI connectors of all things? What requirement couldn’t be met off the shelf?

chipweinberger 2 days ago|
Not technically custom, but made to order (I gave them a spec sheet). If they had reasonably priced connectors on LCSC or DigiKey, etc, I would have used them!
mune2gu-chan 1 day ago||
Love the breakdown here. It's refreshing to see someone build a physical device instead of wrapping everything in another app.
Archit3ch 2 days ago||
I can't wait for ASIC manufacturing to become as easy as ordering a PCB.
crote 2 days ago||
Unlikely to happen any time soon. The problem is mask manufacturing costs: you spend a lot to make a set of masks, but after that making the chips is incredibly cheap. Great for mass production, not so great for prototyping. And there's a lot of proprietary 3rd-party IP involved in chip production: fabs are not very eager to make that publicly available. Heck, even FPGAs are still mostly proprietary!

That doesn't mean it is completely impossible, though. Fab2 (formerly Atomic Semi, of Jim Keller and Sam Zeloof fame) is trying to do exactly this by aiming at making small-scale production affordable. The trick is to replace the whole mask-based lithography with electron beam scanning: way slower, but no mask costs.

But they are now targeting selling mini-fabs to R&D labs rather than offering an affordable ASIC-as-a-Service. Let's hope one of their customers makes it available to the public!

craigjb 2 days ago||
We’re at approximately where PCB pricing was 20 years ago, which _is_ a big deal: https://wafer.space
crote 18 hours ago||
Still a few orders-of-magnitude off, though.

Hobbyist electronics manufacturing has always been reasonably affordable, with the old perfboard / stripboard from RadioShack having been a staple of the hobby since forever. At-home etching was also available for the people who cared more about having cool PCBs than about having healthy lungs.

The availability of cheap factory-made low-volume PCBs goes hand-in-hand with the switch towards smaller and smaller SMD parts. You don't need a professional PCB for a few THT parts, and you can always put the odd SOT part on a breakout or dead-bug solder it. But when many interesting parts started to become available only in QFN/DFN (or worse: BGA) packages, proper PCBs became the only option. Combine that with PCB factories wanting to make a few extra bucks off of their wasted board space, and it is suddenly quite attractive to hack together a quick-and-dirty ordering page for hobbyists and prototypes. No new technology needed, just a new market waiting to be served.

$4 / die custom chips are indeed very attractive, but the $4000 MOQ is not. A high-school or college student just getting into electronics can afford spending $100 on a hobby project just to discover it is broken, but there is no way they can afford spending "used car" money on it. That's startup territory, or "retired Bay Area engineer" territory.

Unfortunately they still run into the same basic economic problems: a wafer might be only $1000, but a set of masks is closer to $100k. This means you want to maximize the number of wafers, with ideally each wafer only containing a single copy of each chip. But even if you assume they just fill a reticle to the absolute maximum with unique chips (let's call it 40 unique designs) and fit, say, only 25 copies on a wafer, that's still only 40 wafers, so $2500/wafer in one-off costs - completely dwarfing the actual wafer itself.

For hobbyists you want a process closer to $10k / wafer with zero mask costs. Fit the same 1000 chips on there as before, and you can now sell people 5 copies of their chip for $50. That's a completely different game!

stevage 2 days ago||
That's a super interesting device. Definitely pondering ordering one.
999900000999 2 days ago||
Very very cool!

It’s actually not hard to hack this together as a .net application and run it on a laptop, but I suspect your target market has a bit of money to spend.

Learning piano is already largely an upper middle class active and after that what’s another 200$ or 300$.

A higher end digital piano is easily over 2k.

Making sure your target market has money is the key take away.

Not sure if this is in scope, but I’d love an easy way for the community to share midi files. I can somewhat do very basic piano progressions, but I still can’t play well.

I’d be grateful if someone would share midi files for me to plugin to my music software. Of course I’d provide full credit

Echo4309 2 days ago||
Good to see some hardware love! Congrats on hitting 2500 units. How’d you decide to make the first jump and actually build your first prototype?
Graziano_M 2 days ago||
> Have a strong anti-counterfeit strategy

What is this strategy? You're building this in China, it's already over.

HNisCIS 2 days ago||
The anti counterfeit strategy is that the volumes here aren't worth it for someone to clone, even if the board and code are dead simple.

These niche hobby products are usually reasonably safe because they rely on community network effects, becoming the darling of a random subreddit or discord group and people aren't going to save $20 to get some device of dubious origin.

connicpu 2 days ago||
I would assume the 200K lines of software and the firmware is presumably flashed after receiving the product from the assembly house.
marysol5 1 day ago|
Vast majority of the hardware, especially as it's running on ESP has already been done for you

>Assembly is just a single screw, for a single PCB. The injection mold has generous draft, no slides.

Says everything

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