My digital camera uses a 2CR5 lithium battery (6V) which is quite expensive and it doesn't last long. Unfortunately, the camera doesn't have an input jack for external power. The manufacturer sells an AC adapter which is a dummy 2CR5 battery with a cable to an external AC supply. I didn't feel like shelling out $80+ so I built one.
The adapter is made from a piece of 1.25" diameter acetal rod. I should have used a slightly smaller diameter, but I didn't have any other material. I sanded the curved sides a bit after machining to make it fit. The adapter fits into the battery compartment of the camera and the wires are connected to an external rechargeable 6V battery pack or AC adapter. The contacts are made of copper clad printed wiring material that I cut to shape and glued in place. The contacts are made more durable by applying a very thin layer of solder to them.