Make:

Nice project from the PopSci folks on instructables -- how to take 1.5V to 5v, and of course jam it in an Altoids tin.

Yes, you read that project title right; this simple circuit will enable you to generate 5V DC from a single 1.5V DC AA battery. How can you pump 1.5V up to 5V, you ask? It's simple with a little piece of electronic steroids from MAXIM IC.

The MAX1674 IC is a DC-to-DC step-up converter that can take in voltages as low as .7V and crank out a digital circuit enriching 5V. Or, for more finicky projects, the MAX1674 can also output 3.3V. A simple pin-selectable preset determines the output voltage.

There is one small caveat with this project, however. Whether a blessing or a curse, the MAX1674 generates a steady-state output current ranging between 180-420 mA. Therefore, high current projects involving motors won't be able to benefit from this voltage amplifying circuit.

On the other hand, powering lightweight projects involving TTL/LS circuitry or LEDs are ideal applications for Voltoids. In fact, with such a low operating current, the MAX1674 is able to drive a 3.3V LED without the ubiquitous power-limiting resistor. All from a single 1.5V AA battery.

If this project seems beyond your talents, but the benefits of powering a digital circuit from a single 1.5V DC power source sounds enticing, you can opt to purchase a similar circuit from Spark Fun Electronics. Costing less than $10, this clever little device which is designed by Bodhilabs.com is housed discretely on the back of an AA battery holder.

Unfortunately, with this commercial product you are limited to a fixed 5V output and it isn't housed in a cool Altoids tin. Enter Voltoids.

instructables : Weekly Project: Voltoids; or, How to Make 5V from 1.5V - Link.