The 111701 is a DC-DC switching booster module that can handle an input between 1 and 5V, and has a fixed output of 5V. It can be found on dx.com and it is the cheapest switching module of its kind I could find, currently priced at 1.47€. Unfortunately I couldn’t find any docs about this module, so here is some of my tests.
The first thing to know about this module is: never reverse the polarity. Things get really hot really fast.
Some specs I gathered:
- Size: 2.6 cm x 1.8 cm x 0.6 cm
- Input: 1-5V
- Output: 5-5.36V (see below)
- Max output current: rated for 600mA (unconfirmed, maximum I got is 420mA for now)
The board also has two screw mounts, not sure about the size (surely less than 3mm, probably 2.5mm). The screws are meant to mount a female USB connector. The board also offers D+ and D- pins for USB purposes; they aren’t wired to anything.
By using 4xAA batteries I measured an input voltage of 5.15V and an output of 5.36V. This might not be a problem depending on your need. Using a single AA battery (input 1.24V) yields a perfect 5.00V. Below is a chart of the input/output voltage I measured.