RoboCar Making Tutorials - PART:3 || Line Follower Robt-Car Using IR Proximity Sensor

Hello Everyone,

GOOD DAY !!! Recently I made some simple Robocar projects for my friend's son. For that I made a report in step by step and also made a video tutorial for all the robo ideas. Total I think around 6 different Robot ideas. So I thought it is better to share all the information with you guys also. Because information is not a thing to hide. So you can use it. If you are facing any issues, you can ask me without any hesitation. I am dividing my Robocar tutorial in four parts, Here it is third part. Let's start....

Limit Switch SPDT three 3 pin 1A/125V or 2A/125V : 6 Nos

Limit Switch SPDT three 3 pin 5A/125V : 4 Nos

Female Spade Crimp Connector Size: Suitable for above limit switch lever (for both) :4 Nos each

170 point mini Breadboard : 1 Nos

3x1.5V AA Battery Box Holder : 1 Nos

IR Proximity Sensor Board : 3 Nos

LM293D Motor Driver Board : 2 Nos

Male-Male breadboard jumper wire : 30 Nos

Male-Female breadboard jumper wire : 10 Nos

Nuts & Bolts

M 2.5 x 25mm (diameter 2.5mm*length 25mm) : 8 Nos

M 2.5 x 10mm (diameter 2.5mm*length 10mm) : 10 Nos

PCB Single Stranded Wire : 4 Meter

Single Stranded Wire 1 mm : 1 Meter

Heat Shrink Tube – 2.5mm : 1 Nos

Double Side Foam Tape : 1 Nos

1.5V AA Cell : 4 Nos

3 mm LED RED : 2 Nos

Resistor 1KΩ ¼ W : 2 Nos

In the previous project we used limit switch to detect the obstacle and based on that the circuit turn the robo car to avoid the obstacle. But it is a contact method which mean that the obstacle detect by touching the antenna on the obstacle. But in this IR sensor method the obstacle is detect without any physical contact. The IR light (radiation) is invisible to human eye, the LED produce the IR light and it hit on the obstacle and the reflected IR light is detect by the IR sensor in the sensor module PCB. In this way we can detect the obstacle very easily and efficiently. But one problem is that this type of IR module is produce false signal when it expose to the sunlight. The sensor will detect the IR light in sunlight as reflected light and produce output. So this type of sensor is only works in dark condition or in the presence of artificial lights such as LED light, CFL light etc… which is not emit IR light. There are some different IR sensor modules available in the markets which are capable of avoidingthe sunlight false triggering by some modulation techniques.

Let’s start our project…

• Remove all the previous project connections and remove limit switches
• Place IR sensor module instead of limit switch
• Fit it by using nut and bolt or use double sided tape
• Take the motor driver module PCB
• Connect the motor wires to the PCB screw terminal using a small screwdriver, do it carefully without applying extra force otherwise it will damage the PCB
• Connections are like white wires to the inside terminal and ash wires are to outside terminals, check the given image (if colours are changed then the motor will rotate in opposite direction)
• Fit the motor drive PCB in the front side of the robocar using double sided tape as given in the image Now the remaining part is the wiring section. Let’s do it….. Wire the circuit based on the given wiring diagram. It is easy to use the same colour wire which used in the wiring diagram and in the real image
• First connect the batteries in series by connecting the ON/OFF switch in-between the two battery boxes
• The +ve and the –ve (red and black) wires from the battery box connect to the breadboard +ve and –ve rail respectively
• Connect the blinking LED circuit as we did in the previous projects
• Connect the IR sensor +ve and –ve (VCC and GND) to the breadboard +ve and –ve rail respectively using male to female jumper wires
• Connect the motor driver board +5V and GND pin to the breadboard +ve and –ve rail respectively (don't connect positive to 12V pin only to 5V pin)
• Connect the motor driver board input signal pin 1 from each side to the +ve rail of the breadboard using jumper wires
• Connect the motor driver board input signal pin 2 from each side to the IR sensor module OUT pin through breadboard using jumper wires, connect left sensor OUT to right side input of the driver board and right side sensor OUT to left side input of the driver board
• Double check all the connections with the given wiring diagram
• Check the circuit by turning on the switch and test the sensitivity of the IR sensor by putting hand in front of the sensor. You can adjust the sensitivity by rotating the poterntio-memter on the sensor board, do the setting carefully otherwise it will damage the PCB

Done!

It is a robocar which will run through a black line. It is always follow the black line and run through the line in any route shapes. We can easily modify the above robocar into a line follower by making little bit change in the circuit. This circuit also affect by the sunlight or any other IR sources. When there is other IR sources the sensor always shows the obstacle detection signal (red LED). So place our robocar away from such IR sources.

Let’s start…..

• We are going to modify the previous project
• Bend the IR LED and IR sensor in downward direction
• Keep both the sensors little bit outwards with a small angle as shown in the given image
• Check the given wiring diagram and follow the given procedures
• Remove both the input signal wires from the motor driver board
• Remove the connection from the IR sensor OUT pin
• Connect the 2nd input signal pin on the driver board to the –ve rail on the breadboard using jumper wires in both sides of the driver board
• Connect the 1st input signal pin on the driver board to the IR sensor Out pin through the breadboard using jumper wires
• The connection is like, left sensor OUT to left motor input signal pin and right sensor OUT to right motor input signal pin on the driver board
• Double check the connection with the wiring diagram
• Make a black line with width of 4c.m (line width must less than the distance between two wheels); you can use black coloured paper or black insulation tape. You can make your own shapes. Here in this case it is a round loop. So the robocar move in a loop continuously. Avoid 90 degree sharp bends.

For proper working you want to fine tune the IR sensor module sensitivity. You tune the potentiometer for satisfying the given conditions.

• IR module give output (red LED on) when it faces the floor other than the black tape
• IR module never give output (red LED off) when it faces the black tape

Theory: When the sensor detect black surface (no output), that side motor will stop and try to again move away from the black surface. In this way the robocar try to maintain both the sensors give output (red LED on) by keeping the black line in between the sensors.

THANK YOU

“Stay Creative and Stay Safe”

Part 3 is Over. Part 4 will Come Soon…………

Please watch Part 3 video for more understanding.

For more interesting projects please visit my webpages,

https://www.instructables.com/member/YADUKRISHNAN%20K%20M/instructables/

https://www.youtube.com/channel/UCTaMdoiwlfG7iGWML0kQKIA/videos

https://0creativeengineering0.blogspot.com/

Created By,

Yadukrishnan K M