An almost no-cost power supply for my Canon IXUS 860 IS. Using CHDK I can do timelapses for hours and days now. Even on the go, if I bring my lead battery.
A diode steps down the 5V from a regular USB port. First I integrated the diode into my modified cam battery, but I didn’t want the camera to become too warm and so then outsourced the diode into the wire.