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  • Any thoughts on a sensible preorder platform? KickStarter's still kind of a pain, especially if I want to offer different PCB types alongside (eg. 0.1" breakout, buttons, plant moisture).

    Someone suggested Massdrop - but the fact that it makes everyone sign up before even browsing makes it very likely a good 50% of people won't bother with it.

    I guess I could just try doing something myself? I've wanted to add a shopping basket to for a while anyway as I'm giving 10% of every sale to Tindie at the moment.

  • Have you any example alpha/beta designs you can share ? You might get some feedback here which will help you narrow your offerings.

  • The only real breakout board I have at the moment is actually what kicked off this thread (the start of the video shows the board layout). It's just the module, with an (optional) voltage regulator if you're going above 3.6v input - then the end of it shares the same pinout as the FTDI cable if you want to program it serially rather than via bluetooth.

    Some simple layouts might be:

    • Arduino footprint
    • Arduino Atmega328p footprint
    • Pi Zero W footprint (there are quite a few 'hat's out there now)
    • Plant moisture sensor
    • BME680/etc sensor board
    • LCD/ePaper display - although some of those are (IMO) too difficult for most people to hand solder so I'd have to be careful
    • Adafruit Feather footprint
    • Adafruit Trinket
    • micro:bit clone

    But obviously there's a balance between offering stuff people are interested in, and actually getting something out there ASAP :)

  • @Gordon Have you seen this ESP-WROOM-32 (ESP32) programming board with spring contacts? I know the nRF52-based MDBT42Q is smaller, but I'm wondering if something similar could be made from one of these boards. I've found this one very easy to work with.­OM-32-Module-Minimum-Development/dp/B071­3PR4RZ

    (If you Google Image Search "ESP-WROOM-32 fixture" you'll see some better images. The ESP-WROOM-32 just clicks into place and stays there until you snap it out)

    Looking at mine, I think you might be able to hack the contacts off one of these and onto your own board, with a Dremel, a tiny iron, some tweezers and a lot of patience.

    Edit: or, come to think of it, if you don't need the short-edge contacts, you could probably just saw out the two rows of side contacts and move them closer together!

  • @tom.gidden that's a thought - I hadn't seen things like that before - they're using a slot in the PCB itself as a guide aren't they? Looks neat - I think the pin spacing is different as well, but with a bit of careful cutting I might be able to get it to fit as you say!

  • Yeah. The springy pin goes through a slot, then loops back and goes through-hole to solder on the other side. The kink in the pin just before it goes through the slot keeps the ESP32 board itself pulled against the base-board. It's 0.05" pitch as far as I can see, but obv. a different number of pins.

    It's silk-screened to hell and back, so I can't see what the connections to the other gubbins on the board are, but some Stanley-knifing with extreme prejudice should work. Anyway, it wasn't expensive. I seem to remember mine came over on the slow boat from Shenzen, though.

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  • Thanks! Looks like a neat idea. The MDBT42s are ~0.7mm spacing compared to that 1.27mm spacing though, so it could be a bit painful to make it work. It wouldn't be so difficult since only 4 pins are needed, but the two SWD pins are right next to each other!

    The current method I have does work fine though, and with minor tinkering (adjusting the angle of the two Pogo pins) would be really easy to use - so there isn't a huge rush to get something better.

    Also, it looks like if I place an order for 100 or more modules I can get Raytac to program them, which realistically is going to end up being quite a bit cheaper. It's really just making sure I'm not stuck with a bunch of modules with out of date firmware - but I'd have thought finding 50 people to buy 2 or more modules wouldn't be too difficult.

  • Great news for small order size, I'd imagine these forums alone will get you well past 100 units. I vote for the small pcb as per the thread :-).

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Next BLE

Posted by Avatar for Adam79 @Adam79