Nowadays, different types of doorbells are available in the market and they produce different types of sounds depending on their circuitry. The most commonly used doorbells in the home produce “ding dong” sound and we can easily design this circuit using basic electronic components.
In this tutorial, we will show how to make a Ding Dong Door Bell Circuit using a 555 timer IC. For this circuit, we will use two 555 Timer IC instead of one.
Hardware Components
Following are the necessary hardware items for Door Bell Circuit:
| S.NO | Component | Value | Qty |
| 1. | Breadboard | – | 1 |
| 2. | Battery | 9v | 1 |
| 3. | Connecting Wires | – | 1 |
| 4. | IC | NE555 Timer | 2 |
| 5. | Variable Resistor | 100k ohm | 2 |
| 6. | Resistors | 2.2K ohm | 2 |
| 7. | Capacitors | 1uF, 47uF, 0.01uF, 0.1uF | 1, 1, 1, 1 |
| 8. | Speaker | 8 ohms | 1 |
Connection
- Place both the 555 Timer IC on the breadboard and connect Pin 8 to VCC and Pin 1 to GND.
- Connect Pin 4 of both the IC’s to VCC.
- Use 2.2K Resistors to connect Pin 7 of both the IC’s to VCC.
- Use a 0.01uF Capacitor to connect Pin 5 of IC (1) to GND.
- Connect Pin 7 and Pin 6 of both the IC’s to Variable resistors.
- Connect Pin 2 of both the IC to the middle Pin (Wiper) of Variable resistors.
- Use a 47uF Capacitor to connect Pin 2 of IC (1) to GND.
- Use a 0.1uF Capacitor to connect Pin 2 of IC (2) to GND.
- Connect Pin 3 of IC (1) to Pin 5 of IC (2),
- Connect a 1nF Capacitor and a Speaker to the Pin 3 of IC (2).
Working Explanation
In this circuit, we are using 2 separate 555 timer IC and both the ICs will operate in astable mode. The output of the first IC is connected to Pin 5 of the second IC. Both the ICs will operate at different frequencies and we can adjust the frequency with the potentiometer. We can adjust the ding dong sound time interval by RV1 and the sound signal can be adjusted by using RV2. The output pin of the second IC is connected to the speaker through a capacitor of 1uF. Pin 2 of both the ICs are connected to the ground through a 0.1uF capacitor. And the potentiometers are connected to Pin 6 and Pin 7 of both the ICs.
Application
- We can use this circuit to make an emergency alarm.
- We can modify this circuit to produce different types of sounds.
Circuit Diagram
