DIY Parking Sensor Circuit using IC 555 and IC LM324

A parking sensor is a cool electronic device that helps drivers park their cars by spotting things nearby that could get in the way.

It uses a special system with an infrared IR transmitter and receiver that work together to figure out how close any obstacles are.

The whole setup has two main parts:

Transmitter Circuit: This part sends out infrared light using an IR LED, which sends signals into the area around the car.

Receiver Circuit: This part picks up the infrared light that bounces back from nearby objects.

It figures out how far away the obstacle is and lights up LEDs to give the driver a visual warning.

Circuit Working:

Parts List:

The circuit diagram above has two main parts:

Parking Sensor Transmitter: This part uses the IC 555 timer chip set to astable mode, which makes it control the IR LED to send out pulsing infrared light.

Parking Sensor Receiver: This section uses an IC LM324 operational amplifier to pick up the bounced back infrared signal and processes it to turn on the LEDs.

Below are the working of transmitter and receiver section in the circuit diagram:

Transmitter Section:

In the transmitter part of the circuit there is a 555 timer chip IC1 set up in a way called astable mode.

This clever arrangement makes the 555 create a square wave output, which powers an infrared IR LED.

This causes the IR LED to send out pulses of infrared light.

The speed at which this infrared signal blinks is carefully controlled by the resistors R1 and R2 along with capacitor C1 using a specific formula: f = 1.44 / ((R1 + 2R2) * C1)

Receiver Section:

The receiver setup includes an infrared photodiode IR LED2 and an LM324 quad operational amplifier.

The infrared photodiode IR LED2 is important because it detects the infrared light bouncing off an object and turns it into a small voltage signal.

This tiny signal from IR LED2 is then boosted by the operational amplifier in the IC2 LM324

LM324 IC2 work as comparator checking the amplified signal against certain voltage levels set by the resistor dividers R7,R8, R9 and R10.

The strength of the signal which shows how far away the detected object is controls the lighting of one or more LEDs LED1, LED2, LED3

This gives a visual clue about how close the object is.

Distance Indication

LED1 is the Green LED which lights up when the object is far away.
LED2 is the Yellow LED which turns on when the object is somewhat closer.
LED3 is the Red LED which lights up when the object is very close.

Formulas with Calculations:

Below are the formulas with calculations for DIY Parking Sensor Circuit using IC 555 and IC LM324:

Transmitter Circuit Frequency (IC 555 in astable mode):

f = 1.44 / ((R1 + 2R2) * C1)

where,
R1 = 10k, R2 = 1k, C1 = 1µF

Substituting the values:

f = 1.44 / ((10,000 + 2 * 1,000) * 0.000001)
f = 1.44 / (12,000 * 0.000001)
f = 1.44 / 0.012
f = 130.91 Hz

Comparator Threshold Voltage:

V_threshold = V_supply * (R_divider / R_total)

Substituting the resistor values for the voltage divider network will give the threshold voltage levels for each comparator.

Example: If R_divider = 1.5k and R_total = 10k, with V_supply = 12V:

V_threshold = 12 * (1500 / 10000)
V_threshold = 12 * 0.15
V_threshold = 1.8V

How to Build:

To build a DIY Parking Sensor Circuit using IC 555 and IC LM324 follow the below steps for connections and assembling:

• Gather all the components mentioned in the above circuit diagram.
• Connect pin 1 of IC1 555 to GND.
• Connect pin 2, 6 and 7 of IC1 555.
• Connect resistor R1 from pin 7 to positive supply of +12V DC.
• Connect resistor R2 between pin 6 and 7 of IC1 555.
• Connect positive of capacitor C1 from pin 2,6 and 7 and negative of capacitor to GND.
• Connect IR LED1 transmitter and resistor R3 from pin 3 of IC1 555 and positive supply.
• Connect pin 1 and pin 2 of IC2 LM324, connect a capacitor C2 and resistor R4 in parallel.
• Connect pin 1 to pin 13 of IC2 LM324 through positive of capacitor C3 and negative of capacitor to diode D1.
• Connect resistor R5 and diode D2 between capacitor C3 and diode D1 and GND.
• Connect resistor R6 between resistor R5 and diode D5 to positive supply.
• Connect pin 3 of IC2 LM324 to GND.
• Connect IR LED2 receiver from pin 2 of IC2 and GND.
• Connect pin 4 of IC2 to positive supply of +12V DC.
• Connect pin 6, 9 and 13 of IC2 to one end of resistor R11 and other end of resistor to GND.
• Connect resistor R7 one end to positive supply and other end of resistor to pin 5 of IC2.
• Connect resistor R8 one end to pin 5 of IC2 and other end of resistor R8 to pin 10 of IC2.
• Connect resistor R9 one end to pin 10 of IC2 and other end of resistor to pin 12 of IC2.
• Connect resistor R10 one end from pin 10 of IC2 and other end of resistor to GND.
• Connect positive of capacitor C4 from pin 13 of IC2 and negative if capacitor to GND.
• Connect pin 7 of IC2 to one end of resistor R12 and other end of resistor to cathode of LED1 and anode of LED1 to positive supply.
• Connect pin 8 of IC2 to one end of resistor R13 and other end of resistor to cathode of LED2 and anode of LED2 to positive supply.
• Connect pin 14 of IC2 to one end of resistor R14 and other end of resistor to cathode of LED3 and anode of LED3 to positive supply.
• Connect a positive of capacitor C5 to positive supply and negative of capacitor to GND.

Conclusion:

This DIY parking sensor circuit is an easy and affordable method to spot obstacles and help with parking your car.

It uses an IC 555 timer to create modulated infrared signals and the IC LM324 chip works with the reflected signals to show how far away things are using LEDs.

You can also improve the circuit by adding buzzer sounds or digital screens to make it even more user friendly.

References:

Parking Sensor 1