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Showing posts with label hardware. Show all posts
Showing posts with label hardware. Show all posts

Monday, 18 January 2016

Watch Prototype Failure

Drat! My watch prototype now only ever looks like this:


There's no response to anything and attaching the battery just causes it's voltage to drop to about a volt, which isn't good. I noticed that the battery voltage had started to drop quite quickly a few days ago, but after coming back from a weekend away I found it was completely dead, the battery at a low voltage and no way to resurrect it.

I'm not too surprised, as I was using rechargeable 2032 batteries and they run at 3.6V not 3V, and the PIC16LF707 has a maximum operating voltage of 3.6V. All would be OK, except that the actual voltage of a charged battery is about 4V, so i have been over-volting the part. So in a way there's good news as I know what the problem is. For the PCBs i have some PIC16F707 parts which I will use, they have a maximum operating voltage of 5V so should be OK. I think the power for that part may be a bit higher, but as I'm probably planning to use rechargeable batteries now that shouldn't be a problem. With the display active all hopes of a long battery life go out of the window anyway...