• Lesson learned from pogo pins: Stick to the standard process for all PCB orders! Do anything non-standard yourself.

    Greg • 07/04/2024 at 21:39 • 0 comments

    Batteries come in many sizes. Even within one size, for example AA allows +/-0.5mm length tolerance. That's 1mm of uncertainty. It's not much, but enough to make having some sort of moving (or flexing) part essentially unavoidable.

    I've tried lots of different design ideas (pics coming soon) for accomodating different battery sizes, including:
    - Two PCBs riveted together (rejected due to short life span)
    - Bent paperclip (worked welll but too unprofessional)
    ...and the pogo pin solution has won.

    Okay, pogo pins it is then. Problem is, that's the only part that I didn't already have in stock and would've had to order from LCSC... and I wanted the boards quickly, so DHL shipping it is for this one... but paying that much TWICE, just to also get few bucks worth of 1 item seemed unjustifiable.

    Idea: Let's add the pogopins to the board spec and add a note:
    "No need to solder pogo pin parts (YTC1P-5025-01). Just please include the parts in the shipment."

    Well, that didn't work. Board didn't get to production and the next morning I saw a response:
    "Sorry that we cannot add the parts to clients' parcels since you and us might meet big problems if the customs check the parcels. Could we ignore your remark for this part and solder the parts as your BOM and CPL?"

    ...what followed was a 12 emails long chain, an additional payment (18$ for 30 boards) and 2 weeks delay, until my boards finally got DHL Express shipped with the pogo pins soldered by the fab. 

    They actually did a good job for the price. I imagine they needed to re-do some of the boards, as it's very easy to accidentally get solder to flow into the pins and disable them. In fact, 2 out of 30 boards had this issue on at least one of the pins and I don't blame them (I should have specified slightly longer pin variant as per render, thought I did).

    I've gone along with the long email chain and all of that, mostly to see what would happen and gain experience for the future. The "special requirement" increased fulfillment time from 2 days to 2 weeks, but they did the job... but then again, 12 emails and 2 weeks, and that was with what I'd call "good communication" and renders like the one below... It's good to know that the option is available, but I know for sure I'm gonna avoid anything non-standard with my future PCB orders.

  • Documentation published, deadline appreciated

    Greg • 07/02/2024 at 01:25 • 0 comments

    Finally! Thanks to the imminent Hackaday Contest deadline, I don't care anymore about making it perfect first. 

    The design files, including some terrible code that makes the thing work, have been published on GitLab. 

    https://gitlab.com/v3611/businesscard-battery-tester

    I'll probably be using Hackaday.io for the more social side and irregularly post major releases here (like, whenever I'll order more cards I guess). Still figuring things out. I've been looking forward to joining the contest and am so glad I didn't miss the deadline.