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gmurphy

Member since Feb 2021 • Last active May 2021
  • 3 conversations
  • 16 comments

Most recent activity

    • 14 comments
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  • in Projects
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    Thanks all - I do have a stencil, but the 2D array of pads makes it much tougher than the edge-contact ones I've tried before (can't visually inspect, and can't fix with a soldering iron), so a lot of my issue is "how do I know if I've got it right".

    Gordon's method ended up being the most successful - the squeezed-out solder balls inspired a lot of terror ("if solder is coming out the side, might it not be squishing across pads internally?"), but everything seems to be working. To mitigate my own terror, in my next version of the PCB I've also omitted the pads I'm not using, which is almost certainly a mistake for a variety of reasons, but its made layout much easier and I can only learn by doing :)

    Attached is a shot of the latest version, with Micro-USB charging. I swapped some pins and setWatch isn't working on the ones I swapped it to (11, 28, 30) - might be a soldering issue again, but just in case the next version goes back to 0,2,3,4,5,29

  • in Projects
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    Despite my first success, over the past 24 hours I've failed at five of them - it could be my PCB design, but regardless of whether I use a hotplate or hot air, I invariably end up either not getting a connection or delidding the MDBT42V. Any tips? Are you using a solder stencil? Very very precisely pasting each pad? Smearing paste on both and heating?

  • in Projects
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    Inductive is a cool idea - I'll take a look, thanks! I would love in the fullness of time to do magnetic/pogo pins/pads and something like a Grepow 160725 curved battery too.

    Soldering the MDBT42V is tough - with my hotplate, hot air gun, and total-amateur skills, it took several attempts to get it connected properly - I eventually found that I needed to apply a bit of downwards pressure to it while soldering to get all the contacts to connect - I guess because my solder paste wasn't evenly distributed so there was a little lift (turns out Raytac even warn about this).

    Not sure you want to sign up for all the bug reports from the consequences of similarly tough soldering situations, but I would definitely buy a few if you stocked them - especially since I bought all the remaining stock Amazon had :)

  • in Puck.js, Pixl.js and MDBT42
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    My meter updates at about 5hz (whereas @AkosLukacs' spikes seem to occur every few seconds), and has been quite good at instantanteous readings so far, but given that no-one else seems to see this I'll tinker some more and report back. FWIW I flashed a second MDBT42V, and that also got the 20uA readings.

  • in Projects
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    No IMU - finger tracking is through an Ultraleap. I'm hoping 2-antenna UWB becomes a readily-available thing faster though.

    Not sure about battery life yet, because I keep making mistakes faster than my testing intervals, but so far it looks like its 11mAH battery can give about a day of paired usage with moderate amounts of clicking (I also use it as my mute button in all my VC meetings).

  • in Puck.js, Pixl.js and MDBT42
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    Thank you Gordon! Adding a capacitor appears to have prevented a bunch of dropouts :)

  • in Projects
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    I couldn't wait for the MDBT42V Espruino, so following guidance from Gordon, flashed one myself and made a little PCB and ring mount for it - the ring is currently bigger than it should be because it'll eventually have micro-USB charging.

    It's mostly so I have a way to press buttons when using hand tracking in flight sims, but it turns out it's good for other things too (see video).

  • in Puck.js, Pixl.js and MDBT42
    Avatar for gmurphy

    Ah that's super interesting - all my modules were purchased in the past month, from a mix of Adafruit and Amazon (I needed next day, so I bought the kit).

    • The official Espruino boards were just flashed up to 2.08_189 with NRF Connect
    • The bare modules were SWD/J-Flashed with espruino_2v00_mdbt42q.hex, then NRF Connect flashed up to 2.08_189

    But interestingly, I also got it running on an MDBT42V (the super tiny new one from Raytac) using the same method, and on that board I do manage to get ~20uA sleep!

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