We have all used something like these battery operated stick-up lights for closets and dark places. And we forget about them. Note: You should check all of your Battery things and devices at least once a year. When Batteries Leak they can damage everything and rust metal contacts. Most of the older stick-up lights use Light Bulbs not LEDs. This is a good thing. Why? You can do more with more voltage. Four AA batteries equal SIX volts. That will run electronics like the 555 timers and Microprocessors (like the Basic Stamps and Arduinos) and that makes much more fun projects.
Get your light and open it up. Clean battery contacts and any places where wires connect. I cleaned off all of the old wires and I had to clean all of the contacts with a wire brush before I could solder to them. A Dremel works great for this.
Modify the basic wiring of your light to fit you plans.
Step 1: Old Light
Find where to tap into the voltages you need. See my wiring diagram. The RGB LEDs use 25 to 60 mA each so three will give you about an evening of fun. The work LEDs use about 200 mA so they won’t last too long, but that is OK. The brighter the LED the more current they use. If you need more power you may need a wall adapter.
Some Professional LEDs have a resister or a circuit in them that controls the current and voltage for that LED. They do not light up until they reach their minimum operating voltage. These LEDs can usually run up to 9 or 12 volts, but test them first. My work light LEDs work perfectly at 6 volts and that is all I needed. I did completely rebuild my light and re-do all of the wiring. My work LEDs were not bright enough through the dome so I moved them to the rim.