A long time ago, we discussed battery contacts: http://lists.en.qi-hardware.com/pipermail/discussion/2016-March/011018.html http://lists.en.qi-hardware.com/pipermail/discussion/2016-March/011019.html
I eventually settled for the Keystone 5225 / 5203 pair. Let's see how this turned out. First, we need a place to put the contacts, a sort of pockets at the ends of the battery compartment where the case holds the contacts in place. After an embarrassing start that 1) was prone to cracking, and 2) would have required teleportation for proper assembly ... http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/designed-for-teleportation.jpg ... I eventually came up with a more solid solution, one that doesn't require applied Sci-Fi: http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/contact-plus.jpg http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/contact-minus.jpg In the latter image, we see from left to right: - the side wall, - a step in the side wall, leaving room for the bottom shell, - the rear wall of the contact pocket, supporting the contact and leaving room for the cable, - the space where the base plate of the contact goes, - the front wall of the contact pocket, with an opening for the spring (minus) or nipple (plus) With the battery inserted, it looks like this: http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/with-battery.jpg Prying the battery from the compartment can be a bit difficult, but one can eject it by simply slapping Anelok into one's palm. I still have to test if the spring tension is sufficient for preventing disconnection when the device falls to the floor or such. In any case, it's easy to adjust the length of the battery compartment. This all may look pretty, but does it actually work ? Let's find out ... http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/battery-working.jpg It does indeed ! Now, what started the whole discussion was the idea that one could design the contacts such that a reversed battery would not make contact, and thus couldn't cause trouble: http://lists.en.qi-hardware.com/pipermail/discussion/2016-March/011017.html Let's see what happens ... http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/battery-reversed.jpg This is what the plus side contact looks like when the battery is reversed: http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/plus-reversed.jpg And here is it with the correct orientation: http://downloads.qi-hardware.com/people/werner/anelok/tmp/battery-contacts/plus-normal.jpg It looks a little tight, perhaps 100 um. The wall has a thickness of 1.2 mm, so I may still be able to make it slightly thinner before it starts to crumble. - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
