Introduction: Elisen Lebkuchen - Musicbox - Non Stop Sound!
In Germany they bake these wonderful "Elisen Lebkuchen". It's a special from the city of Nuernberg. They also sell these cookies in music boxes as agift ( http://www.lebkuchen-markt.de/ , http://www.manufactum.de/Produkt/193510/779545/ElisenlebkuchenSortiment.html ).
After winding up a spring the music i beeing played. It costs some energy to wind up the "music player", so that you have to eat some Lebkuchen ... ;-)
After eating all the Lebkuchen, how can you manage to hear the nice music while beeing so weak?
Just put a motor in and keep it running, powered by battery. This instructable shows you how ...
Step 1: Dismantling
Looking inside the box the music mechanism can be seen. Take it out of the box.
There is a black plastic housing that contains the spring and some gear wheels. It needs to be removed because we want to take out the spring and get rid of some other unused parts.
The housing is held by some bolts. Use a dremel tool to remove the top of them. Now carefully pull of the plastic housing. Try not to break it because you need it later. Be very careful with the cylinder containg the music. After the housing is taken off, pull the spring out.
Step 2: Reassembly
To make the thing work you need a small motor that is strong enough to turn the cylinder. The motor also needs to run on low speed. I found this one in an old ccd camera. The motor was used to adjust the autofocus of the camera. The motor contains some gear. That makes ist strong and slow.
Mount the motor onto the plastic housing with some hot glue.
Now you have to do a test run. In my case the motor ran too fast. I had to slow it down. Therefore I built a small pwm generator with the famous NE555 timer. It would be ok to use a Arduino too but I think there to much tiny microprocessor circuits around already ;-)
Using the trimmer you can adjust the speed of the motor. The values of the timing resistors and the timing capacitor are just examples. Depending on the motor you have you may need to find other values. If the frequency is too low the motor will rattle and that does'nt sound well, does it? If the frequency is to high the motor will "sing", very much like a small speaker.
Step 3: Listen ...
Btw. if you have a baby that needs some music to fall asleep, and this takes longer than a standard music box plays, this may be something for you. Just add a second timer that switches of the motor after some minutes. You may use the famous 556 double timer for that ... or is THIS really some thing for a microprocessor?