Melody Door Ringer


In all the houses exist the bells in the door. All want, they have the possibility of being possible to change the intensity, the tone of sound. With this circuit we have this possibility. With the materials round the gates, we can change the sound. For the materials that exist in the circuit the frequencies are roughly 5 KHZ and 2 KHZ. The circuit functions only for small time interval afterwards the pressure of switch. Simultaneously with the sound we have also optical clue from LED D2. Changing the capacitors C2-C3, with different price of capacity, we create new sounds.

Circuit diagram

Circuit diagram

Part List

  • R1=470Kohm
  • R2=22Kohm
  • R3=3.9Kohm
  • R4-5=330 ohm
  • R6=2.2Kohm
  • R7=1.2Kohm
  • C1=22uF 25V
  • C2=470uF 25V
  • C3=1 uF 25V
  • D1=1N4001
  • D2=LED RED 3mm
  • IC1=7413
  • Q1-3= BC 550
  • Q2= BC 560
  • BATT=4X1,5V or external pack 6Vdc
  • SP= Speaker 8R /0,5W

All Resistors is 1/4W 5%