Touchless sanitizer dispenser Using NPN Transistor BC547

Circuit Description:

1. NPN Transistor (BC547):
   • The NPN transistor is used as a switch. It is controlled by the output of the infrared proximity sensor.
2. Infrared (IR) Proximity Sensor:
   • The IR proximity sensor detects the presence of a hand or object in front of it without physical contact.
3. Resistor (R1):
   • R1 is connected between the positive voltage rail and the base of the NPN transistor. It is used for biasing the transistor.
4. Diode (D1):
   • D1 is connected in reverse-bias across the solenoid or pump to protect the circuit from voltage spikes.
5. Solenoid or Pump:
   • The solenoid or pump is activated when the NPN transistor is turned on. It dispenses sanitizer.

How It Works:

1. The infrared proximity sensor detects the presence of a hand or object in front of it.
2. When an object is detected, the sensor sends a signal to the base of the NPN transistor.
3. The biased NPN transistor turns on, allowing current to flow through the solenoid or pump.
4. The activated solenoid or pump dispenses sanitizer without the need for physical contact.
5. When the object is no longer detected, the sensor signal decreases, turning off the NPN transistor and stopping the dispenser.