For my next project I thought it would be cool to make a custom made doorbell for my house. I used the following items for this project:

• The cheapest glockenspiel I could find on e-bay.
• Arduino Duemilanove
• 2 l293b H-Bridges
• 8 small solenoids

To get the system running just connect 8 outputs from the arduino to the 8 h-bridge inputs (two h-bridges gives 8 inputs, and 8 outputs). Then connect one wire from each solenoid to ground, and the other wire from each solenoid to an output from the h-bridges. At this point you can control all solenoids from the arduino.

To get the solenoids to work as a result of a doorbell ring, you must install some kind of button. On the duemilanove all of the I/Os are floating, that is ok for the solenoids, but for the button input a pull-down resistor is needed. Once the button and pull down resistor are installed, an interrupt can be connected to the input line on a rising edge and when it fires you know someone has pushed the doorbell which means it is time to play a tune.

The code for this project is at github.

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