This will show you how to add a timer... plus add a much larger battery supply. The voltage of 4.5v is the same, but the D Cell batteries will run a whole lot longer!
Wikipedia tells us that a AA battery has 1/5th of the life power (Amperage) in relation to a much stronger (and larger) D Cell. A D Cell will simply last longer when in use.
Buy a Fling-ama-String for your feline, they'll love it! After you've plugged the third set of AA Batteries in it, you'll be back here for sure!
This modification will make a great toy quite economical!
Here's Gracie, playing with her Fling-ama-String:
Here it is... shown in a mirror so you can see both sides....
Step 1: Parts Needed
Step 2: Size Up a Piece of Wood
Step 3: The Wiring Explained
We're going to connecting the BLACK wires to the RED wires, just like shown here.
This is called "SERIES" wiring. http://en.wikipedia.org/wiki/Series_and_parallel_circuits
Step 4: The Timer Added to the Circuit
Step 5: Mount Hook
If you want to go "low tech", you could also use a small "eye" hook (no need to pre-drill a hole), and then loop a piece of cord through it- to hang over the door knob. You don't have to get as fancy as this bicycle storage hook, but for 40 cents, why not?
Step 6: Connecting the Wires- Various Methods
Shrink tubing is easy to use. Twist your wires together really well- I like to then bend the joint over in a hook loop. Then cut a piece of tubing to fit. Shrink it down with a heat source. Another cool thing you can get at Radio Shack.
Step 7: Secure the Components to the Board
I tucked the wires up and behind the battery holder to keep it neat.
Step 8: What It Should Look Like
Let's put some batteries in....
Step 9: Connect the New Power Supply to Your Fling-ama-String
Touch the POSITIVE (+) RED lead to the flat coiled-up spring in the upper right hand corner of the Fling-ama-String battery case.
Touch the NEGATIVE (-) BLACK lead to the cone shaped spring in the lower left corner of the Fling-ama-String battery case.
The toy should operate and the band should be going in the proper direction. If not, reverse the wires at the battery compartment springs in the Fling-ama-String battery compartment.
Me? I just smoosh the wires into the springs. You can wrap the wires around the sprigs, or you can get real fancy and get tiny "alligator clips" to bite them with. Unnecessary, but another Radio Shack item for $1.
Step 10: The Battery Door Cover
I was too lazy to go to the basement for a file, didn't want to bother with my Swiss Army Knife, so I used a nail file that my wife left laying around. Just cut a notch. If it's snug, that would be good. That way, it won't allow any tugging of the wires from the outside. That might cause the wires to come off the springs- and kitty wouldn't want that!
Step 11: Set It Up
You would never want to do this with a regular household current power line, but a tiny 4.5v line is not dangerous. This narrow door frame gap is why you might want to buy and use multi strand "speaker wire' while you're at Radio Shack. It's thin and very flexible. If you use scrap lamp cord (extension cord wire), it's a lot thicker- so your door's closing might be blocked.
Step 12: Sit Back in Wonderment
You'll find that these D Cell Batteries seem to last forever (certainly when compared to leaving the original standard 3 AA Batteries run down if you leave the room).
Remember- to operate, the switch on the Fling-ama-String should be left in the "on" position. Control the power to the unit by a twist of the timer.
Kitty likes Fling-ama-String!