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How to Build an Electric Music Box

Music boxes are mechanical devices that play music automatically. To build an electric music box, use a 4017 decade counter and two 555 timer ICs. The decade counter functions like an electrical switch that can control 10 components. The components for the music box are diodes, which limit the direction of the current, and resistors, which change the sound. The 555s are used as Schmitt triggers. Schmitt are able to control input noise and create clean rectangular waves. If a large breadboard cannot be obtained, combine two or more small ones to hold all the parts.

Things You'll Need

2 555 timer ICs
4017 decade counter
8 1N4158 diodes
3V Piezo buzzer or speaker
2 33k-ohm resistors
3 10k-ohm resistors
3 15k-ohm resistors
2 22k-ohm resistors
33uF capacitor
10uF capacitor
0.01uF tantalum capacitor
2 AA batteries
Battery holder
Large Breadboard
Jumper wires

Instructions

- 1
  Insert the 555 and the 4017 chips into the breadboard. Their notches must face left, and they must all occupy separate columns. Their individual pins must also be in separate columns. To do this, insert each one so that it straddles the upper and lower sections of the breadboard. The two 555s must be near each other.
- 2
  Select a row or column on the breadboard that will serve at the plus voltage source. Select another row or column as ground.
- 3
  Wire the first 555. Connect pins 4 and 8 to the positive voltage source, and use a jumper wire to connect pins 6 and 2 together. Add one end of a 33k resistor to pin 3, and the other to pin 2. Add one end of the first 10uF capacitor to pin 2, and attach the other to ground. Attach pin 1 to ground.
- 4
  Connect the second 555 exactly the same way as the first, except insert the 0.01uF tantalum capacitor between pin 2 and ground. Place one end of the second 10uF capacitor at pin 3, and its other end into an empty column. Connect the positive side of the buzzer to this column, and attach its negative side to ground.
- 5
  Wire the 4017. Connect the positive end of the 1N148 diode to pin 1, and insert its negative end so that it is vertical to the breadboard. Use the same method to attach diodes to pins 2, 3, 4, 6, 9, 10, and 11.
- 6
  Connect a 10k resistor vertically to pin 3. Its other end must be connected to ground. Use the same procedure to connect the two other 10k resistors to pins 4 and 9. Likewise, connect the 15k resistors to pins 1, 2, and 9, and the 22k resistors to pins 10 and 9.
- 7
  Attach pins 8, 13, and 15 to ground. Connect pin 16 to the plus voltage source.
- 8
  Connect the 555 chips to the 4017. Place a jumper wire between the first 555's pin 3 and the 4017's pin 14. Connect a jumper wire between the bottom of the resistor at the 4017's pin 1, and the second 555's pin 5
- 9
  Place the battery inside of the holder, and connect the holder's wires to the plus voltage source and ground. The music will begin playing.

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