RE: Month of Robots - MeArm test update

dubbie — Mon, 17 Jun 2019 10:14:38 GMT

James,

Well done on working out battery life and getting it accurate. I have done some battery calculations like this myself and gettingaccurate results is quite difficult. It can depend on the current flow when in operation, how long you use the current for and the time between uses. Being a chemical process there are all sorts of osmosis, depletion areas and recovery times to consider. My best result was a system that came on once every hour using an interrupt to move out of sleep mode, which flashed an LED if it was dark, comprised of a an low voltage 8 pin PIC powered by two AA batteries. It had an engraved block of Perspex above the LED with a logo on, which was created as a give-away for a conference. The case/holder was a 3D printed spring affair. It was all designed to promote the electronics, programming, manufacturing and design capability of the University. My prototype lasted for over two years with the same batteries and I retired before the batteries ran out so I never found out it's maximum life.

Dubbie