4 ms·

My point is that even if your supplier plays fair, the manufacturer may change the designs slightly and you either dont't get the PCN or fail to understand the

by kosma 10y ago

My point is that even if your supplier plays fair, the manufacturer may change the designs slightly and you either dont't get the PCN or fail to understand the implications of a change. We had a case once where a manufacturer added a minuscule hole on the case of a relay, presumably a pressure vent. Our devices are potted in resin in order to withstand rough conditions; in this particular case the resin penetrated the relay and blocked the contacts. We were halfway through a production run before anyone noticed. Needless to say, the run had to be scraped because there's no economical way to remove the resin once it's hardened. All for a saving of a few cents per relay. QA lesson: new batch of anything = tight quality control. When you go into manufacturing, it becomes a game of numbers. Manufacturing 10000 of whatever is statistically bound to generate some duds and failures. Speaking of prototype/hobbyist amounts: stick to the big suppliers and you should be safe, but if something feels fishy, don't be shy to order the part from a different supplier. Generally, identifying counterfeit parts in prototype amounts can be tricky without prior experience because your manual soldering skills will always be sub-par to a pick'n'placer; same goes for ESD precautions, accidental shocks applied to the circuit, passerby finger-pokers and your curious boss.

i336_ 10y ago
Thanks so much for clarifying the specifics of what happened to you; this is one of those situations that's hard to imagine, making it that much harder to envisage exactly what can go wrong, where and how. What I'm wondering now is whether it's possible to somehow financially insure a specific level of quality control (translation: sticking to the blueprints!) in a way that doesn't scare everyone off. I'm guessing the scrapped run had to be eaten on your side? :/
- kosma 10y ago
  Whenever I see an inexperienced young hardware startup striving to build even just 1000 of some widget, I feel sorry for them. They often go twice over the planned budget both in terms of time and money... and only after several screwups they hire some experienced guys to help them with the process. The answer to your question? It simply experience. Start small, try to build bigger things, and put in actual time and effort to learn. Don't cut corners; learn how the big industry does things (and especially: why). Don't guess tolerances and sizes: find relevant standards. Read datasheet thoroughly and with comprehension. Ask your assembly house for guidance. Get a book or two on process & quality control. The effort you invest will pay itself off sooner than you think. Not in revenue, mind you - but greatly reduced losses and delays. PS. The world of manufacturing is wonderful. It's vastly different from programming, as it involves much more interaction with suppliers, vendors, teams and assembly line employees - but the feeling of holding a finished product in your hand is worth it.
  - i336_ 10y ago
    Thanks very much for this info. For a few years now I've wanted to build a handheld device that captures the essence of Lisp machines, Forth, and systems like the Commodore 64 and Canon Cat, in a portably accessible/usable form, wrapped in a highly pocketable but ruggedized enclosure similar to the old Nokias that lasted forever. I envisage it primarily as a teaching device and something people could hack on for fun, but the whole idea has never been especially practical or marketable. Now I know what it might be for (when I have a bit of money) - manufacturing education :) since device production has always been something I'm interested in and I do want some experience. I also want to build a handheld device with a 2G+ baseband, secure boot, and an open-source firmware (perhaps seL4, most definitely not Android). The possibilities start with end-to-end encrypted SMS and trail off infinitely. I haven't really thought of what might be possible; I'm just stuck on the academic problem of secure boot - which is quite an issue, as not even Apple (just checked, $641B valuation right now) seem to be able to get this right: https://ramtin-amin.fr/#nvmedma https://ramtin-amin.fr/#nvmedma. I'm saddened by the fact that all secure boot implementations seem to either be NDA-laden, based on security by obscurity, or both. I'm yet to find something I feel would be hard for even someone with a very very large pile of money (for arbitrary scaling of "very very large") to break. I realize that given infinite money everything is breakable, but current "secure" defenses seem to fall over much too readily IMO. (Eg, secure boot implementations have to have test modes; have these passed stringent code verification? A properly-formed legal case could subpoena any secure boot implementation's source code. This is assuming the likely-overly-idealistic case where there are no deliberate backdoors.)
    - kosma 10y ago
      My advice? Start small. You might want to build a car, but in order to do this, you first need to build a dozen skateboards before moving on to bicycles. As for Secure Boot - it takes expertise in breaking things to build something unbreakable. I have broken commercial copy protection using nothing but an adjustable power supply and some assembly code - protection that, on paper, seemed "good enough". If you think you can build something secure without decades of experience, you haven't really understood how much power a determined engineer equipped with a fast FPGA wields over your puny electronics.

by kosma 10y ago

i336_ 10y ago

Thanks so much for clarifying the specifics of what happened to you; this is one of those situations that's hard to imagine, making it that much harder to envisage exactly what can go wrong, where and how. What I'm wondering now is whether it's possible to somehow financially insure a specific level of quality control (translation: sticking to the blueprints!) in a way that doesn't scare everyone off. I'm guessing the scrapped run had to be eaten on your side? :/

kosma 10y ago
Whenever I see an inexperienced young hardware startup striving to build even just 1000 of some widget, I feel sorry for them. They often go twice over the planned budget both in terms of time and money... and only after several screwups they hire some experienced guys to help them with the process. The answer to your question? It simply experience. Start small, try to build bigger things, and put in actual time and effort to learn. Don't cut corners; learn how the big industry does things (and especially: why). Don't guess tolerances and sizes: find relevant standards. Read datasheet thoroughly and with comprehension. Ask your assembly house for guidance. Get a book or two on process & quality control. The effort you invest will pay itself off sooner than you think. Not in revenue, mind you - but greatly reduced losses and delays. PS. The world of manufacturing is wonderful. It's vastly different from programming, as it involves much more interaction with suppliers, vendors, teams and assembly line employees - but the feeling of holding a finished product in your hand is worth it.
- i336_ 10y ago
  Thanks very much for this info. For a few years now I've wanted to build a handheld device that captures the essence of Lisp machines, Forth, and systems like the Commodore 64 and Canon Cat, in a portably accessible/usable form, wrapped in a highly pocketable but ruggedized enclosure similar to the old Nokias that lasted forever. I envisage it primarily as a teaching device and something people could hack on for fun, but the whole idea has never been especially practical or marketable. Now I know what it might be for (when I have a bit of money) - manufacturing education :) since device production has always been something I'm interested in and I do want some experience. I also want to build a handheld device with a 2G+ baseband, secure boot, and an open-source firmware (perhaps seL4, most definitely not Android). The possibilities start with end-to-end encrypted SMS and trail off infinitely. I haven't really thought of what might be possible; I'm just stuck on the academic problem of secure boot - which is quite an issue, as not even Apple (just checked, $641B valuation right now) seem to be able to get this right: https://ramtin-amin.fr/#nvmedma https://ramtin-amin.fr/#nvmedma. I'm saddened by the fact that all secure boot implementations seem to either be NDA-laden, based on security by obscurity, or both. I'm yet to find something I feel would be hard for even someone with a very very large pile of money (for arbitrary scaling of "very very large") to break. I realize that given infinite money everything is breakable, but current "secure" defenses seem to fall over much too readily IMO. (Eg, secure boot implementations have to have test modes; have these passed stringent code verification? A properly-formed legal case could subpoena any secure boot implementation's source code. This is assuming the likely-overly-idealistic case where there are no deliberate backdoors.)
  - kosma 10y ago
    My advice? Start small. You might want to build a car, but in order to do this, you first need to build a dozen skateboards before moving on to bicycles. As for Secure Boot - it takes expertise in breaking things to build something unbreakable. I have broken commercial copy protection using nothing but an adjustable power supply and some assembly code - protection that, on paper, seemed "good enough". If you think you can build something secure without decades of experience, you haven't really understood how much power a determined engineer equipped with a fast FPGA wields over your puny electronics.