Build a RC car that uses ultrasonic sensor to detect objects in front of it. And cuts power to the forward motion when reaches a certain distance from an object (specified in code) while retaining the ability to move backwards.

Step 1: What You Will Need.

With your Arduino, you will need:

1: 9v battery

1: ultrasonic sensor

1: Red LED(any will work)

1: 220ohm resistor

1: Transistor(NPN-2222)

1: Diode Rectifier

1: 5v Relay

Step 2: Use RC Car

Use a RC car, any model should work, and cut out sections of the top large enough for the ultrasonic sensor and battery to fit in the front and back respectively.

Note on pictures: We used cardboard pieces to act as "blinders" for the ultrasonic sensor. Not specifically needed...Entirely up to you.

Step 3: Build the Brain

Assemble your Arduino circuit board as shown in the diagram. One thing to note, is that when you hook up the Arduino to the RC car's motor you will need to cut the wire from the motor to the RC mother board in order to connect to the Arduino. .

Note: There should be a Trigger and an Echo pin for the ultrasonic sensor, Trigger goes to pin 3 and Echo goes to pin 2