Bell cum Light Controller

—> Many times it happen when somebody comes home in night and press the door bell, We search for the porch light switch. To identify that the visitor who as press the door bell is known or unknown person before opening the door. This circuit will help you to solve the problem.

—> When a visitor press the doorbell switch it will automatically on the porch light after sometime so that when you reach near the door you don’t have to search for light switch.

—> This circuit will automatically off the light after some time.

—> This bell with automatic light circuit also has the facility to on the porch light from inside the house.

—> In day time you can off the light with the help of switch S3.

—> Doorbell cum light has inbuilt doorbell so you do not require to purchase a door bell.

—> You can connect a bulb through a relay which can be operated with help of AC.

This simple circuit is built around a commonly known IC CD4060, melody generator IC UM66 and few more components.

IC CD4060 is 14 stage ripple carry binary counter, divider and an oscillator. Its built in oscillator is main feature of this IC that’s why it can be used in numerous application like flasher, clock generator in timer circuits.

Fig. 1: Pin Diagram of CD4060 IC

Hear IC1 CD4060 is working as frequency dividing circuit. Its inbuilt oscillator is based on three inverters. The basic frequency of the internal oscillator is determined by the value of the capacitor connected to its pin 9 and the resistor connected to pin 10. By increasing or decreasing the value of capacitor and resistor we can change the time delay for the period of on and off. Internally the oscillator signal is applied to the first bistable which drives the second bistable and so on. Since each bistable divides its input signal by two, a total of fifteen signals are available, each of half the frequency of the previous one. Output Qn is the nth stage of the counter, representing 2ⁿ, for example Q4 is 2⁴ = 16 (¹/₁₆ of clock frequency) and Q14 is 2¹⁴ = 16384 (¹/₁₆₃₈₄ of clock frequency). Note that Q1-3 and Q11 are not available. Pin configuration of is shown below-

Working of this bell with automatic light circuit

Before understanding the working first of all understand the use of three switches-

1.Switch S1 – It is used to on the porch light from inside the home. Install the switch S1 inside the home near to the door.

2. Switch S2 – It is used to on the porch light and doorbell by the visitor. Install the switch S2 outside the door.

3. Switch S3 – It is used to on and off the light. In day time off the switch S3 so that bulb will not glow and in night on the switch S3 so that bulb will glow to light the porch.

Fig. 2: Prototype of CD4060 IC based Bell Cum Light Controller

When a visitor come and press the switch S2 it will bring the transistor T2 into conduction and the bell start sounding for a specific period of time. When switch S2 is released it will reset the pin 12. When this pin goes high it will start the counter and first output Q4 pin 7 goes high( refer pin diagram) for specific period of time. Time period is set with the help R3 and C1 then pin 5 output goes high similarly all output goes high, and when Q13 pin 1 goes high it will bring the transistor T1 into conduction and relay connected to it will energize and on the bulb(we have connected LED in our circuit) for 15 sec approx. You can connect bulb at any of the output according to your requirement.

From the circuit diagram you can see that we have connected the pin 2 of IC1 to pin 11 with the help of a diode so that when 2 goes high it will disable the counter until reset pin 12 again goes high. So that bulb will only glow when a switch is press next time.

Now you want to on the light from inside just press switch S1 it will again reset the pin 12 to high and counter starts so that when you reach near the door light will be on. Note that this will only on the light not the bell. And in day time you want only doorbell than off the switch S3.

If you want to increase or decrease the time period for which light remain on. You can do it just by changing the value of resistor and capacitor connected at pin 10 and pin 9. When you increase the value of resistor and capacitor time period will increase and when you decrease the value time period will decrease.

Component used