At night, parking lights make your parked vehicle more apparent to passing cars, reducing the risk that they will collide with it. However, these lights will draw a significant amount of electricity from the battery in your vehicle. The following description is of a straightforward automatic parking light system that requires no standby current to function. When the light of an oncoming car is detected from either the back or front side, the circuit is programmed to switch on the parking lights automatically for a period of thirty seconds. This automatic feature offers increased protection to a parked car during the night. Circuitry for an automatic parking light system The circuit is constructed using discrete components along with the transistors T1 through T3, the MOSFET T4 (BS170), and other transistors. The front and rear sensors are represented by the Darlington phototransistors T1 and T2 (both of which are L14F1) When the light from an incoming vehicle shines on the relevant photo- transistor, it causes transistor T3 to current, which in turn triggers the gate of MOSFET T4 via resistance R3. When resistor R4 and capacitor C1 are energized for a certain amount of time, relay RL1 becomes energized. This turns on the parking lights (B1

through B4) that are connected to its N/O contacts. When the allotted amount of time has passed, the relay labeled RL1 will become deactivated, which will result in the parking lights being turned off. Construct the circuit using a PCB designed for general use and enclose it in an appropriate housing. Mount the front and rear phototransistors (T1 and T2) in such a way that they receive light directly from an approaching vehicle rather than receiving light from an ambient source such as a street light. Install the 12V bulbs marked B1 through B4 in the appropriate locations inside your car or outside in the parking lot.