Some things seem like, for all time, they will evoke a response. The humble music box, the plinking of tines on a rotating drum… falls right into that category for me. This Happy Birthday Song Mechanical Music Box has been brought wonderfully into the modern age by means of a DC motor and a small PCB.
It’s quite elegant! Looking at the pictures on the product page, the rotating drum with the tine actuating pins on it has a gear on the edge. There is then another gear meshed and a shaft running out with another spur gear on the end which sits on a worm gear on the DC motors output. The motor is hooked up to two pins, EN and GND. If you apply a PWM signal between 3 and 5V to the EN pin you will enable the drum to turn and the music to play. Of course, varying the PWM means that you can vary the tempo of the playback.
Over on the product page, you can find an example where they have hooked up the device to an Arduino and patched in a rotary encoder and a button. They can then use the button to start and stop playback and the encoder to vary the tempo. While the Arduino demo is great, we can imagine it being pretty straightforward to hook this up to any microprocessor. Adding sensor-based control for example could lead to some fun projects.
If nothing else, it’s a wonderful electro-mechanical way to say happy birthday to someone and could be incorporated into a wonderful gift!
