Jingle Bells playing Christmas Tree

 

Jewi from Germany built this Jingle Bells playing Christmas Tree that will actually teach you how to play Jingle Bells. It uses an ATmega to play the song on a speaker and at the same time it lights appropriate LEDs on a keyboard display. You can see on the project page that Jewi used a bunch of SMD parts in the project where some large parts with some large leads might have made construction a bit simpler. The code is available here if you want to make your own.

 Via: HG Forum

 “We have 9 control lines for the LEDs and 1 line for the speaker signal. We want the device to start playing if a push button is pressed and when done playing the device shall be switch off automatically. For this, we use a pushbutton in parallel to a relay switch which is controller by the ATmega. If someone presses the push button then the ATmega starts running and holds the relay closed.”