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What I learned selling 2,500 MIDI recorders: Hardware is not so hard

chipweinberger.com

201–210 of 276 posts

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#201

Earlier quoted context omitted.

> "actual regulations...emissions" yeah, and looking at their board I see they use one of "ESP32-WROOM" modules, which has the wifi & blutooth & antennae (pre-certified by Espressif for FCC, CE so itself doesn't need testing) & flash & processor (which even has its own RC oscillator), which takes care of a whole ton of difficult stuff so all the designer needs to do is plop that module down and power it up and wire s…

Im not an expert in emissions testing but pretty sure it still needs CE certification testing. The module shouldnt cause any problems providing that the firmware for the transmitter is configured properly, and is placed sanely in the enclosure, but the entire product must still undergo the relevant testing for 2.4GHz emitters. Just because you use a certified module doesn't give you a free pass.

> but the entire product must still undergo the relevant testing for 2.4GHz emitters.

To be fair, it's unintentional radiator testing that's required, rather than everything the module had to go through as an intentional radiator. So, it is a "free pass" for nearly all of it, and a much cheaper one, since you don't have to use a costly FCC accredited lab.

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#202

Earlier quoted context omitted.

> "actual regulations...emissions" yeah, and looking at their board I see they use one of "ESP32-WROOM" modules, which has the wifi & blutooth & antennae (pre-certified by Espressif for FCC, CE so itself doesn't need testing) & flash & processor (which even has its own RC oscillator), which takes care of a whole ton of difficult stuff so all the designer needs to do is plop that module down and power it up and wire s…

Im not an expert in emissions testing but pretty sure it still needs CE certification testing. The module shouldnt cause any problems providing that the firmware for the transmitter is configured properly, and is placed sanely in the enclosure, but the entire product must still undergo the relevant testing for 2.4GHz emitters. Just because you use a certified module doesn't give you a free pass.

It does still need CE certification and emissions testing. I’m guessing they didn’t do that and it will be fine because they only sold 2,500 units.

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#203

Hardware has a reputation for being hard for three reasons. First, it scales differently than software. It's far harder to design something you want to make a million of than something you want to make ten of. Second, it's harder to anticipate, test, and correct all the things that can go wrong on the user end. Some people will put batteries the wrong way, some will drop the device on the ground, some will connect it…

>your JS is too big, you can't ship until you get it under 50 kB Back in the glorious past, the iOS App Store either didn’t allow apps larger than 100 MiB, or at least forbade them from being downloaded over mobile connections. There’s an old blog post/Twitter thread you can find on Hacker News where an Uber engineer describes the challenges they faced in trying to keep their app under that limit. They were also rewr…

Blog posts:

https://www.uber.com/us/en/blog/how-uber-deals-with-large-io...

Comments about a Twitter thread talking about the same thing: https://news.ycombinator.com/item?id=25373462

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#204
post #194
post #179

Earlier quoted context omitted.

The ESP32-S3-WROOM1 module is FCC certified for its own Wifi and Bluetooth emissions when used by itself. And, well -- that's certainly good. But the FCC rules cover more than just Wifi and BT, and the whole rest of the widget also needs to comply with them. Of particular interest is FCC Part 15 Subpart B, which covers unintentional radiators . The device would need to comply with Part 15 Subpart B even if it had not…

A fun fact of the CE mark, is that it's also used to signal "Chinese Export" deceptively, with the marks being almost identical beyond spacing.

Of course there’s no actual official ‘china export’ mark and that is just what some Chinese factories were claiming when they were caught slapping a (accidentally mis-spaced) CE conformance mark on their products! The EC made a statement on this back in 2008 [1] so everyone knows what game they are playing.

1. https://www.europarl.europa.eu/doceo/document/P-6-2007-5938-...

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#205
I thought 'hardware is hard' is a VC statement to apply a broad stroke for why its hard to make succesful hardware companies (that gives 100x returns)

For reasons other commentors have already mentioned-scale, logistics, revisions. And for reasons they havent mentioned-cash flow

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#206
post #35

Wow, congrats, I remember reading your HN post. I hope you will continue writing blog posts on your journey, I expect quite a lot of software engineers would be very interested going though a similar journey now that LLMs removed most of the fun of programming. It’s neat to work on something physical for a change

> quite a lot of software engineers would be very interested going though a similar journey now that LLMs removed most of the fun of programming.

I suspect we will see a reversal on this. LLMs are flat out worse than humans at programming (yes, even your latest favorite frontier model). I am faster (once you factor in the time fixing its inevitable mistakes) and better at programming than Claude is, and I'm not a particularly exceptional programmer. People say "they aren't going away", but I disagree with that - already we've seen people disenchanted with the lack of results compared to what they pay, and that is only going to grow once the AI companies raise prices in an attempt to turn a profit rather than lock people in. Eventually the industry will wake up and stop drinking the kool-aid, and what matters will once again be the results you deliver, not the tools by which you deliver them. But it's hard to say when that will happen, and it's going to be rough in the meantime.

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#207

Very happy to hear about your success! I'm curious to hear more about your anti-counterfeit strategies beyond just enabling encryption. I'm curious if you feel like anti-counterfeit and open source firmware are mutually exclusive. I made the choice to embrace an open firmware approach on my project while keeping the hardware closed, while knowing that if someone tries hard enough they can completely reverse engineer…

You don't need an X-ray for a board this simple. Every component has well defined input and outputs. Give a mildly competent freshman EE student or high quality high school student you could have the board recreated in a few days.

Low product quantity and low quality/fake products resold on amazon from AliExpress are the biggest roadblocks at this point. The juice isn't worth the squeeze.

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#209

Earlier quoted context omitted.

> "actual regulations...emissions" yeah, and looking at their board I see they use one of "ESP32-WROOM" modules, which has the wifi & blutooth & antennae (pre-certified by Espressif for FCC, CE so itself doesn't need testing) & flash & processor (which even has its own RC oscillator), which takes care of a whole ton of difficult stuff so all the designer needs to do is plop that module down and power it up and wire s…

> Without something like those ESP32 modules, this would be much more difficult. I don't disagree. It's important for us to recognize that we stand on the shoulders of giants, but I also think it's a little silly of a critique of someone happy about it being easier than he expected. It's true that hardware would be much harder if you had to do it all yourself, but is that meaningful? The wonders if the modern supply…

Well the title and premise is a bit silly. If you're designing easy hardware by wiring parts together that already do all the hard stuff, then "hardware is not so hard" is something you might conclude, but that only applies for designing easy hardware like this. But if you are doing anything that pushes the limits or involves analog signals and having to worry about signal integrity and EMI and impedances and Laplace transfer functions all that other stuff that requires degrees, then "hardware is hard".

Re: What I learned selling 2,500 MIDI recorders: Hardware is not so hard

#210
Long time customer! I bought one after your original post on HN. Congrats on the milestone. Honestly, it's such a good product and I'm such a bad and inconsistent piano player that I completely forget it exists for months at a time. Then I remember about it, open the app, and everything is there: my attempt to figure out a song, my kids smashing the keys as hard as they can, my cat walking across the keyboard. It's such a joy.
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