Basically we have an Ultrasonic sensor that measures the distance and the LED’s bar graph will light up according to our distance from the sensor and as we get closer the buzzer beeps in a different way. This circuit can work as a parking sensor! It's easy and cheap.

Components Used:

 

1x Arduino
1x 74HC595 8 Bit Shift Register
1x Breadboard
8x LED’s (for example: 3x red, 3x yellow, 2x green)
9x 220 Ohm Resisters
1x Buzzer
1x Ultrasonic Sensor (for exemple: HC-SR04)
Jumper Wires