Parking Lights are extremely useful especially during night. These lights will assist you to park vehicles in your garage properly and avoid damage of your vehicle from hitting nearby objects. This parking lights circuit uses light beam from headlight of your vehicle to detect the incoming vehicle and turn the garage lights accordingly. You can operate this circuit in manual mode to hold the light control as well.
This circuit uses a simple LDR to detect the incident light from the vehicle. It was paired with a simple variable resistor RV1 to form a voltage divider which feeds the bias voltage for the transistor. The Transistor was used as a switch here to turn ON/OFF the relay connected with it. The Relay in turn will be used to turn a Lamp or any high power light connected to it.
The circuit can be operated in both Auto and Manual mode where a SPDT switch was used to toggle the mode. When Auto mode is selected Transistor will be used as switch which will be controlled by the LDR and RV1 pair. This pair automatically turns the Transistor and in turn relay when light is incident on it. Meanwhile in Manual mode a simple switch was used to turn the relay ON and OFF.
Now to set up the above circuit the LDR must be exposed to Light from the vehicle in darkness and adjust the RV1 until the relay turns ON. This makes the potential divider section to provide bias voltage to the transistor only when vehicle light is incident on it and this makes the relay to turn ON at the same instant.