You can order the AASaver from my hobby shop. The kit comes with a pre-soldered circuit board, four AA battery clips, a pair of bright white LEDs and resistors (for use as flashlights), and two 2-pin headers (for use as breadboard power supply).
When your electronic devices report that the batteries are ‘dead’ and need to be replaced, do you ever feel frustrated that there is often still a lot of juice in them? Don’t throw away the batteries yet! You can use the remaining energy to do a lot of things, such as powering LED flashlights. This is possible by using a boost converter, which can bump the low battery voltage to a higher voltage, enough to light up LEDs or even power breadboard circuits.
Based on Microchip’s MCP1640, the AASaver is a small boost converter that can help you harvest the remaining energy in AA batteries. It has a few nice features:
- Takes up to two AA or AAA batteries. Start-up voltage as low as 0.65V.
- Outputs regulated 5V or 3.3V, selectable by an on-board switch.
- Up to 300mA output current (actual current output depends on the battery condition and the selected output voltage).
- Fits two on-board flashlight LEDs, so the circuit can be used directly as a flashlight.
- Three sets of pinouts to provide power for breadboard.
It works perfectly as a small flashlight. The boost converter generates enough sustained current to power bright LEDs. Even running on a single low-voltage battery (starting 0.65V), it can still power the LEDs for a long time. Now I never have to worry about keeping fresh new batteries for my flashlights — I have so many old AA batteries that are pronounced ‘dead’ by various electronic gadgets, remotes, clocks. I can use them all! This makes me feel a little greener
I also enjoy it a lot as a compact breadboard power supply. It does not require any external power adapter, which is quite convenient. It also allows me to choose between 5V or 3.3V output, which is flexible. With a pair of fresh AA batteries, it can provide more than 300mA output current, enough for many breadboard circuit experiments.
Version 1.1 has the following changes from v1.0:
- Moved both flash LEDs to the same side so they point to the same direction.
- Added an on-board resistor (R1) for the flash LEDs.
- Added a separate flash LED switch.
- Moved the power switch to the bottom side.
These changes were made to improve its usability and convenience.
To find out usage details, including how to use it with only one battery or AAA instead of AA battery, check out this page.
The schematic and board design are available for download here.
Feel free to leave a comment or suggestion below. Thank you.
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