Some electric toothbrushes are marketed as disposable by manufacturers. After three months of use, it is recommended to replace them with new ones. But can a thrifty home craftsman find use for an old brush?
Unscrew the round cover located at the bottom of the brush. The battery will fall out. After three months of use, it will, of course, be almost discharged, but its charge is quite enough to work for a certain period of low-power load. Try to connect it, observing the polarity, for example, to an electronic clock with an LCD indicator, or to a homemade LED flashlight with a Joule Thief type converter. In any case, do not place the battery inside the load, but outside: despite the fact that the brush is sealed from the inside, by the end of its service life the seal is broken and the battery shows the first signs of corrosion.
Then pull out the plastic frame with the motor. To do this, you will need miniature pliers. Nippers will not work. Disengage the two latches that secure the frame to the brush body, then pull it out towards you.
On the frame you will find a simple rocker switch and a motor. Separate them from each other. If they are wet, wipe them dry and then dry.
If you decide to give your child a homemade electric corset, the switch and the motor will come in handy. The first one is equipped with dielectric pushers of any design. Then install these parts on the stands, and place the clamps on them for connecting to other circuits. It remains to connect a 10-volt two-anode zener diode in parallel to the engine (or its analog of two zener diodes connected in series by the cathode to the cathode). This is necessary to protect children's fingers from self-induction surges. Remember that such a motor is designed for a voltage of 1.5 V.
It remains to find a use for the brush itself. Remember how often the do-it-yourselfer has to wash plastic items. A toothbrush that is no longer suitable for its intended purpose is perfect for cleaning plastic. Together with it, use any dishwashing detergent - but in very small quantities. Of course, the housings of electronic equipment can only be cleaned separately from the contents, and must be thoroughly dried before assembly.