====== Need ======

Power a sensor or other 5v thingy from one of those common portable battery-powered cellphone rechargers.


Problem: those portable battery packs that output usb power for phone recharging have a **minimum** current requirement: draw too little and they figure the phone must be fully charged and they shut down completely.

====== Prototype ======

{{ :usbbattery-sensorpower.jpg?600 |}}

TODO: explain

====== Future/Improvements ======