chipweinberger

The app is not required if you access the midi files from the sd card. You don't even need to install it.

The app is optional, and its for browsing your library. Think of it like the Photos app but for MIDI.

Counterfeit != clone. I welcome competitors. They can help grow the pie.

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.

I appreciate the critiques!

First, so far, there have been 0 failures in the field. My email address is on the website, the app, and the first page of the instruction sheet, so I'd probably know if there were.

But since it's fun, I'll address some of these :) I'm not flying by the seat of my pants here as much as you expect.

- The ESP32-S3 includes ±2 kV ESD, which is respectable. Adding more is a bit precautionary IMO, but I did add it in some places where the user is more likely to touch metal (like the USB ports). The sdcard's metal housing is not exposed.

- The AMS1117 is just more available than the alternatives. Again, no failures yet so seems like the right tradeoff was made here.

- Supercaps don't last long enough for my liking. A CR2032 can go for 10+ years. A supercap, only weeks. I want correct dates even if the device is left unpowered for months.

- The 0603 47ohm resistor is a good callout. Worth beefing that up. But at 3.3v and 232 mW it's not a fire hazard. It will fail open.

- USB-B for power was very intentional. It's a great firm connector and more importantly prevents users from plugging it into their piano wrong. Many of my customers are in their 70s or older.

- USB-A for data was made for manufacturing simplicity, but again, USB-C is too complicated for many of my users. I'd only switch to USB-C if both ports could be used interchangeably, but they can't be / it's not worth the complexity.

- As for the software moat, time will tell. You can't stave off competition forever!

- The device is FCC and CE compliant.

Again, I actually do appreciate your critiques!

500 units was my first run, and it worked out really well. None of the suppliers complained about that order size. I recommend starting with a smaller quantity until you've validated the market. The "economies of scale" between 100, 500, or 1000, units are not all that dramatic. Perhaps 30% cost difference.

I was originally planning to do 4000 units as my first run. Boy I'm glad I started to run out of money and cut it way back. That would have been way too much as a first run.

The device does not require the app. It still records MIDI 24/7 to sdcard.

It's more the opposite. The app requires a genuine device.

Will do a write up on injection molding and anti-counterfeit!

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!

The marketing answer: all lower-case looks modern and opinionated

The real answer: I got tired of deciding what should and shouldn't be capitalized. Sounds easy but it gets ambiguous fast.

I'll revisit this decision at some point. Capital letters do make reading easier.

Yes the anti-counterfeit is primarily app enforced (though entirely offline). I do use the firmware encryption features of the ESP32-S3, whatever that is worth, and the firmware is tied to the HSM.

Ahah good eye. It was only 4 blocks down the road! I too was surprised by how well a single cord worked to balance the 45lb boxes.

Android too! Built with Flutter. Flutter is great highly recommend it.

This is very flattering. Thank you.

3 main components: flashing, provisioning keys, hardware testing.

Nearly every component gets tested: sdcard, clock, battery, anti-counterfeit IC, led, buzzer, the tactile-switch!