It can be tough to assess distance when parking a car if you are a new driver. The reverse parking sensor circuit solves this problem by using three LEDs to indicate the distance. This system is simple to set up in the back of the automobile. This system is powered by a rechargeable 12V battery. This guide will show you how to create a reverse parking sensor. The same approach can be applied to an IR Water Level Detector Circuit.
The set of LEDs can tell how far away the car is from the obstruction (D5 to D7). D7 will illuminate if the distance between the car and the barrier is 25cm. D7 and D6 LEDs light on at a distance of 20cm, and all LEDs (D5, D6, D7) glow at a distance of 5cm. When the distance between the LEDs exceeds 25cm, all of the LEDs will turn off.
- Reverse Parking Sensor Circuit Principle:
- Reverse Parking Sensor Circuit Diagram:
- Reverse Parking Sensor Circuit Design:
- How to Operate this Reverse Parking Sensor Circuit?
- Reverse Parking Sensor Circuit Applications:
- Limitations of this Circuit:
Reverse Parking Sensor Circuit Principle:
The parking sensor circuit is divided into two portions, one for the transmitter and the other for the receiver. The NE555 timer IC is used as an astable multivibrator in the transmitter part to drive the IR transmitter. The frequency of the transmitter is set at 120Hz.
Because of the obstruction, the IR pulses sent by the IR transmitter are reflected back and received by the IR receiver.
The U2:A amplifies the receiving signal. The Peak detector’s output voltage (R4 and c4) is proportionate to the distance between the car bumper and the obstacle. The peak detector’s output voltage is fed into the inputs of three comparators: U2: B, U2: C, and U2:D. The input and reference voltages cause these comparators to flip the status LEDs on and off.
Reverse Parking Sensor Circuit Diagram:
- NE555 timer
- IR transmitter
- Electrolytic capacitor – 1uF, 16V
- Resistors – 10k, 1k, 330 ohm
- LM324 IC (low power quad op-amp)
- IR receiver
- 1n4148 diodes – 2
- Electrolytic capacitors – 100u (2), 10u, 47p, 1u
- LED’s – 3 (5mm)
- 1k resistors – 7
- 1M ohm resistors – 2
- 4.7k , 1.5k resistors
- 12V DC battery
- Connecting wires
Reverse Parking Sensor Circuit Design:
A 555 timer is used in the transmitter part to generate a signal with a frequency of 120 Hz. To avoid unexpected resets, the 555 timer’s fourth pin is connected to the power supply. The output pulse is generated by the 555 timer’s third pin. The output frequency of the 555 timer is set by resistors R1, R2, and C1.
The operational amplifier U2:A amplifies the signals received by the IR receiver. To identify the peak of the amplified signal, resistor R4 and capacitor C4 build a peak detector.
Op – amp as Comparator:
The op-amp has one output and two inputs (non-inverting and inverting). When the non-inverting voltage is greater than the inverting voltage, the output of an operational amplifier is high.
When the inverting voltage is greater than the non-inverting voltage, the output voltage is low.
The voltages at the non inverting pins of the comparators serve as a reference voltage in the aforementioned circuit, and the inverting input voltages of the comparators are compared to the reference voltages to create the output.
Here resistors R8 to R11 are used to set different reference voltages at their non inverting pins.
Resistors R12, R13 and R14 are used to protect the LED’s from high voltages.
How to Operate this Reverse Parking Sensor Circuit?
- Connect the wires as shown in the circuit diagram.
- When an obstruction is present, arrange the transmitter and receiver so that the IR receiver receives the IR rays.
- When you turn on the power and move the obstacle beyond 25cm, you’ll notice that no LEDs will light up.
- Reduce the obstacle distance to 25 cm, and the D7 led should now shine.
- Reduce the distance to less than 20 cm, and both D7 and D6 leds will light up.
- Even if the distance is reduced to 5 cm, all LEDs will turn on.
Reverse Parking Sensor Circuit Applications:
- This circuit can be used in auto mobiles to park the vehicle safely.
- We can use this circuit to measure the distance.
- We can also use this circuit as IR Liquid Level Detector by making few modifications.
Limitations of this Circuit:
- IR receiver may receive the normal light. As a result, parking sensor may not work properly.
- We should arrange IR sensors accurately; otherwise they may not detect the obstacle.