Hack Notes CVA 090619

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North Paw Hack Notes, June 19th, 2009[edit]

New Jack Part[edit]

Old jack part was 10mm tall, huge! New part is CP-036D-ND, only 5mm tall. Footprint was tricky - stat sheet is very misleading about the size of the contacts, and Eagle complained, and then we found real size...

Sample of Display Loop[edit]

I contacted Buy Loop and Hook today and they (a) don't have any "strips" or "ribbons" of the Display Loop material but (b) do send out samples of the material. We will be getting a 1'x1' piece of gray display loop, should be sufficient to evaluate whether it will work for us.

Searching for Small Enclosure[edit]

Turns out enclosures are very hard to search for. After much agony, I found only a couple of suitable parts. But first, some criteria: we wanted plastic (cheaper, doesn't short, lighter, etc), we needed at least one and preferably two "panels" (ends that are removable/customizable), and wanted small: <3x2x1, and we wanted some kind of mount points for a PCB. The hardest part was the height: almost everything is more than an inch in height. In fact we finally had to settle on this front.

The part we chose finally: PanTec JM-22, 2.4 x 2.2 x 1 in, 2 screws, enclosure presses against PCB to hold it in place, 2 panels. $2.84 for <100, $2.20 >=100. Eric will try to get samples, or purchase several if necessary.

Other parts and links that might be handy for other people: Industrial Enclosure - too long for us, but they do have small heights. Hammond Mfg - either too tall, or too long. PolyCase - nice size, but lacks panels. SimcoBox - too big, lack of panels.

Velcro Enclosures[edit]

Eric proposed that the exposed side of the armature should just be made of a velcro strip, because we have so much velcro on it now anyway (for the closing mechanism, mounting for both the electronics and battery chamber). This would greatly simplify armature sewing, leaving basically only four steps:

  • zipper to rayon
  • zipper to velcro
  • velcro to rayon
  • velcro hook (small piece) to end of velcro

We might also need to have velcro "latches" to go over the electronics and battery and hold them more firmly i place - this needs to be tested.

Skory also found a velcro ribbon with sticky stuff on the back - perfect for use on the battery pack and electronics as part of the kit. Some distributors thereof:



Board Design[edit]

With the new low height jack, low height cap, and enclosure dimensions, we feel ready to move unto actual layout of the board. Skory says he's going to work at home on it this weekend.

Small Motors Anklet Works[edit]

I (Eric) finally have a complete working anklet again. I am using the smaller size motors that I got in China. I have to run them at full power (255) to feel them properly - they seem fine with full power. The battery is held with velcro, but the electronics I still have in a pocket. It's a genius idea to rotate the electronics board - the way it is now, the ribbon cable can't help but be way above the armature, making it look funny. Once we get the jack on the side, it'll be possible to internally route it and have only minimal exposure, which will be awesome. Same for the (now necessary) power wires.

NorthPaw SmallMotors Beta1PCB.jpg