I was on Show and Tell two weeks ago and I demonstrated my project called AASaver. Thanks a lot for providing this great opportunity for DIYers to talk about projects. Here are some details about my project, in case you find it interesting to post on Adafruit blog.
What is the AASaver? Simply speaking, it is a small boost regulator (based on Microchip’s MCP1640) that converts the voltage from two AA batteries to a selectable 3.3V or 5V, which you can use to power breadboard xperiments or use directly as LED flashlights. My main motivation to work on this project is that I have collected a large bin of old AA batteries that have been reported ‘dead’ by various gadgets like remote controls, computer mouse, keyboard, smoke alarm etc. I measured the voltages on them and found that they still have quite a bit of juice in them. So I thought about designing the AASaver circuit to help me harvest the remaining energy in these batteries.
The AASaver has on-board high luminance LED lights, which make it directly usable as an LED flashlight. The brightness can be changed by switching between the two votlages. I have a number of these around my house: they are all powered by almost ‘dead’ batteries. As a flashlight, they can last for a long time. I also want the circuit to be dual-purpose — I designed pin headers that match standard breadboard, so I can plug it directly into a breadboard for my circuit experiments that require 3.3V or 5V supply. I find this really convenient as it only needs two AA batteries instead of a DC power adapter. Of course, for breadboard power supply, you will get higher current output if using fresh batteries.
The details of the project can be found at: