This ible (instructable) will not show you how to hack something into a useless item that's only nice to look at, it won't show you how to make an overcomplicated gadget, it will not take you months to accomplish, and this ible will not cost you your firstborn to make. If you are looking for any of these things in an ible you may be disappointed with this how-to. In this quick and easy (and very low cost) Ible I'll show you how I hacked my Crest Spinbrush into a money saving power tool. This will not only save you money, but you are likely to use and benefit from it every day (hopefully at least twice a day)!
The Crest Spinbrush as it comes out of the package is easy to use, cleans your teeth quicker than traditional toothbrushes, is effective, very cheap (I've seen them for as little as $5), and only operates on 2 AA batteries. This is all very nice for about two weeks when you realize you will need to replace the batteries soon. After about a year of constantly changing batteries I decided to do a little tweaking and this "hack-brush" is the result. With the hacked spinbrush you will be able to clean your teeth even quicker than the original spinbrush, it will be more effective, and you will never need batteries again, saving you more money!
Step 1: Parts
Step 2: Precautions and Power
The instructions that follow are very technical, please have a physics book, several electronics reference guides, and a computer programming manual nearby to assist with the process. Just kidding, this will be the easiest project you've ever done. All joking aside now be advised, the misuse or mishandling of the tools (dremel, hot glue gun, wire strippers) can be dangerous; however unlikely, don't kill yourself hacking your toothbrush. Ok, let's begin!
First we will prepare the power source
For this we will be using a used cell phone charger. If you don't have one ask around. I don't know anyone that doesn't have an unused charger in their junk drawer. If that doesn't work you can always find chargers at your local electronics store. Notice that most cell phone chargers (I haven't seen differently) have an output of 5 volts. The AA batteries supplied the Spinbrush with 3 volts (1.5 volts * 2) so we will have a gain of 2 volts. More power for you!
Cut off the end that attaches to the cell phone, I used wire strippers for this. Strip the sheath exposing the two wires inside to about 1/2 an inch. Now strip the two wires exposing the copper wires. Set this aside and move on to the battery cap.
Step 3: Dremel Time
Drilling through the Cap
Now that the wire is ready we need a way to get it into the battery compartment. Take the battery compartment cap and look inside. You'll see the wire coil that connects to the batteries. Remove this with some needle nose pliers or any other way you can. Mine just came off when drilling through the cap so no worries if you don't remove it first. On the bottom of battery cap is a small notch, at least there was on mine. Take your dremel with an appropriately sizeddrill bit and (using the notch as your mark) drill through the cap.
Feel free to take a break here, grab a beverage, maybe a snack, and pick up when you're done. Next we'll attach the wires to the toothbrush.
Step 4: Wire It Up
Attaching the Wires
Take the cap that you just drilled. Make sure the wire coil is gone from the inside. Now slide the wires through the cap, outside to inside. Give yourself some slack for this next part. Solder one wire to one of the metal pads on the inside of the Spinbrush where the batteries used to be housed. Then solder the second wire to the remaining pad.
Plug in your soldering iron and allow it to get hot, I was able to do this easily with a 15 W iron from radio shack. Apply a small amount of solder to the tip of the iron. Apply solder to one of the pads by holding the tip of the iron to the pad. As the pad heats up hold the tip of a strand of solder to the pad until it melts into place. Remove the iron and the solder, if it didn't work try again. You may need to brace the spinbrush in place to prevent any unwanted movement. Repeat to second pad.
To apply the wire to the pad hold the copper tip of one wire to one of the pads (actually to the solder on the pad) and at the same time apply the tip of the iron to the solder. This will heat the solder joining the copper wire to the metal pad. Repeat this process with the second wire and second pad.
Step 5: Waterproof It
To prevent any leaks I used a hot glue gun to waterproof the hole where the wire is inserted into the cap. I glued around the wire on the inside and the outside. Once this has dried I also applied glue around the cap where it snaps into place with the body of the toothbrush. For added safety always use your tweaked Spinbrush on a GFCI outlet.
Edit (16 Nov. 2011):
I understand it sounds scary to use this in your mouth when it is plugged into a wall. It's completely safe, just make sure it's plugged into a GFCI outlet. For further reference check out this article on GFCI outlets.
That's it! I hope you enjoy your new toothbrush in all it's spinning glory! Don't forget to VOTE for this ible in the Hack it Challenge!!!