Introduction: Simple Contactless Infra-Red Controlled Car

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About: I am an electrical student who likes to work with different electronics. I have been working on a different project for years now and I can't wait to share it with everyone!

In this project, I will be building a simple car for my small brother. This car contains two infrared sensors at the back so you can control/steer the car by just placing your hand.

I have used only basic circuitry to make this project, no microcontroller or coding is needed. Let's start with the equipment needed.

I made this project originally back in 2019 and I cant wait to share it with everyone!

Supplies

List of tools needed:

2 x BD136 PNP transistor

2 x TCRT5000 infra-red sensor

2 x 220-ohm resistor

2 x 1n4007 diode

2 x DC motor

3 x DC motor wheels

2 x 18650 Li-ion battery

2mm PVC boards

Connecting wires

Glue gun

Step 1: What It Does?

I can control and steer the car with my hand! As you can see from the video above, I have placed a lot of load over the car just for fun :)

Step 2: Working Principle

The sensor contains two parts, sender and receiver. The IR led continuously sends an Infrared wave. Any obstacle that is not black reflects an IR wave and it can be detected by the IR receiver.

The IR receiver is basically an NPN transistor whose gate is light-sensitive. So if infra rays hit the base the transistor turns on (it is basically acting as a switch).

When the sensor detects an object it supplies base voltage to the PNP transistor. This transistor is connected to the motor. As the PNP transistor turns on, it turns the motor on.

Step 3: Outline the Base

I have used a pen and paper to outline the base of the car. This sketch would help me while cutting the PVC boards. It also helps to visualize the dimension and make any modifications if needed.

The PVC boards can be cut using an anti-cutter. Be careful while cutting the boards!

Step 4: Assemble the Motor

I approached the simplest ways to build the project. Thus, I used some zip ties to connect the motor to the base. Each motor is connected via two zip ties mounted on the base.

Step 5: Attach the Sensors

I made two rectangular holes using the anti-cutter to attach the sensors. The orientation of the sensor is important. If possible mark the pinouts of the sensor using a pen.

Step 6: Circuit Diagram

Batteries:

The two batteries connected in series supply 8V to the circuit

Switch:

The switch, connected in series, connects the battery with the circuit

IR sensor:

Anode of the IR emitter is connected to the positive supply via a 220ohm resistor

cathode of the IR emitter is connected to the ground

Collector of the IR receiver is connected to the base of the PNP transistor

Emitter of IR emitter is connected to the ground

Motor:

Collector of the PNP transistor is connected to one pin of the motor

The other pin of the motor is connected to the ground.

A diode is connected parallelly to the motor to prevent back emf.

Step 7: Complete

Connect all the circuits as shown in the circuit diagram and you are done! Even though this is a simple project it is quite fun to play with.

The design is not perfect, there is a lot of room for improvement. I have plans to add additional sensors to make it more interesting! So stay updated.

I hope you have learned something from this project and will be able to apply it in real life. Cheers!!