2 Digit Door Bell Counter

A 2-digit doorbell counter electronic project circuit can be useful for keeping track of how many times someone has visited your home or office.

To build a 2-digit doorbell counter electronic project, you will need the following components:

1. 2-digit 7-segment LED display
2. 74LS90 decade counter IC
3. 74LS47 BCD to 7-segment decoder IC
4. NPN transistor
5. Diode
6. Resistor
7. Capacitor
8. Push-button switch
9. Doorbell or buzzer

Here are the steps to build the circuit:

1. Connect the doorbell or buzzer to the input of the circuit.
2. Connect a push-button switch between the input and ground. This will allow you to manually trigger the circuit for testing purposes.
3. Connect the output of the doorbell/buzzer to the clock input of the 74LS90 IC.
4. Connect pins 1, 2, and 3 of the 74LS90 IC to ground.
5. Connect pins 8 and 9 of the 74LS90 IC to Vcc.
6. Connect pin 10 of the 74LS90 IC to the reset pin (pin 4) through a capacitor and resistor in series.
7. Connect the output of the 74LS90 IC to the input of the 74LS47 IC.
8. Connect the 7-segment LED display to the output of the 74LS47 IC.
9. Connect a transistor and diode in series to the anode of the LED display to provide sufficient current to drive the display.
10. Connect the common cathode of the LED display to ground.

Once the circuit is built, the 2-digit LED display will show the number of times the doorbell has been pressed. Each time the doorbell is pressed, the 74LS90 IC will increment its count by 1, and the 74LS47 IC will decode the count into BCD and display it on the LED display