The new prototype is coming along nicely. I've now placed most of the components. Besides rfkill acting as system-kill, the design seems to be free from embarrassing mistakes so far.
Top view, without OLED: http://downloads.qi-hardware.com/people/werner/anelok/tmp/brd1-top-0818.jpg Top view, with OLED: http://downloads.qi-hardware.com/people/werner/anelok/tmp/brd1-oled-0818.jpg Bottom view: http://downloads.qi-hardware.com/people/werner/anelok/tmp/brd1-bot-0818.jpg Cheat mode alert: the memory card holder isn't soldered. There are a number of traces that pass underneath it and I'm a bit concerned that it may short them. If that happens, fixing it would be somewhat messy. So I'll keep that experiment for later. The ugly mess of colored wires should of course disappear. Side view: http://downloads.qi-hardware.com/people/werner/anelok/tmp/brd1-side-0818.jpg Note that the two boards (main and battery) will not be at the same height, so there won't be the sort of huge empty space this picture suggests. You may wonder why it's taking me so long to put together the board this time. After all, this is something that should take a day or two, not weeks. The reason is that I'm also measuring the system's idle current (and sometimes other parameters) when adding a new component. This is to make sure that any troublemaker I may add will be found quickly, not after it can hide comfortably in the company of a dozen other equally untested components. The list of current measurements begins here: https://gitorious.org/anelok/anelok/source/0be9a73015cf8ada190d8d6b568bacab94717c91:fw/2014/main.c#L51 So far, things look reasonable. The poorly fitting VUSB diode D1 costs about 1.2 uA, but this can be improved. When disabled, the boost converter draws about 1.5 uA more than expected. Not sure why. The FETs gating power to display and memory card work well, despite measurements that look horrible. The trick there is to look at the system current and not at the the leakage current. Since the FETs have very little leakage (less than 100 nA), the latter basically floats and picks up noise from the air. The overall result so far is that idle current with only the RTC operating is below 6 uA. I have yet to try to make the capacitive sensor work in low-power modes, but I think it should be possible to stay below 10 uA on average, allowing Anelok to sit in a drawer for something like two years on a fresh CR2032 cell. Of course, once you turn it on, power consumption jumps up by a factor of about 1000. But that's the next part of the story ... - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
