Difference between revisions of "Hack Notes CVA 090619"

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(North Paw Hack Notes, June 19th, 2009)
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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.
 
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.
 
==BOM Pricing==
 
 
Eric went through all the parts in the BOM today and figured out pricing for 1, 10, 25, and 100 "kits": $57.72, $53.12, $48.15, $45.97.  This includes a FIXED $10 for the custom board + custom armature.  Additionally, there may be a couple more dollars in discounts on the compass for the 100 quantity - parallax doesn't give that discount level. I think it clearly shows that ~25 is the right quantity to target for the first run of kits - it gets us most of the price break, without making capital outlay too much (25*$50 = $1,250).  Since the compass actually breaks at 20, we could actually buy 25 of those things which break at 25, and only 20 compasses, as a kind of compromise point.  We'd just just to keep the extra 5 parts for the next round...
 
 
The only problem is that we have only ~124 motors, enough for only 15 kits (and this includes 24 more expensive motors).  Furthermore, the pricing assumes the 50 cents from China motors, not the $2 from the USA motors.  So we'd have to get ~80 more motors from the Chinese company to finish 25 kits, otherwise face paying over $10 more per kit... I wish I had just bought 200.
 
 
It looks to me like $50 would be a very aggressive price for the first round of kits - more reasonable would be $59.
 

Revision as of 01:42, 20 June 2009

North Paw Hack Notes, June 19th, 2009

New Jack Part

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

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

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

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 peice) 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.

Board Design

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.