This is the circuit diagram of car parking guard based IR sensor to detect the distance between car bumper and garage wall. this circuit which will help the person in the driving seat and give alarm if there is any obstacle or a wall while parking or while driving in reverse. While parking the car the driver should be more careful because he cannot see the back of the car while parking or taking reverse, if there is any obstacle and ran over it might be get damage to the car.
This circuit was designed as an aid in parking the car near the garage wall when backing up. LED D3 illuminates and the buzzer beeps when bumper-wall distance is about 100 cm. In this manner you are alerted when approaching too close to the wall.
All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity.
- The Q1 photo detector picks-up the infrared beam generated by IR LED1 and IR LED2 and reflected by the surface placed in front of it.
- IR LED1, IR LED2 and Q1 are placed facing the car on the same line, a couple of centimeters apart, on a short breadboard strip fastened to the wall. Q1 picks-up the infra-red beam which generated by IR LED1 and IR LED2, and reflected by the surface placed in front of it.
- If there is a obstacle the IR beam will radiate back to the IR sensor and the 20KHz modulated signal is given to the pin3 of LM567 through photo Darlington transistor, at this point the pin8 of the LM567 is turned to low and also gets locked to detect the 20Khz signal. By this the LM555 is turned low and disabled by this the led will remain lighting and buzzer makes the continuous sound to alert the driver.
Mount this car parking guard circuit at the back bumper and placed at the center. The piezobuzzer and LED indicator should be placed on the dashboard so the driver able to hear the sound alert clearly and can clearly see the indicator LED.
Make the connection to the reverse indicator light and the circuit in parallel and beware of the polarity (not to reserve).