IR module sensor query for Line Follwer Robot

Question

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Are the IR sensors used in Line following Robot and Obstacle avoidance Robot with Arduino UNO different ? If yes , where do we buy these parts online ? I used the following sensor in my Line Follower and am not getting result as it’s detecting obstacle instead of black line .

Answer 1

The sensor you have used is fine. There is a potentiometer on the sensor PCB that is used for the range. For the line following robot you would want the range small, between 1-4cm. However, for the obstacle avoidance robot you would want to set this for a much larger range, say 10-45cm.

To make an effective line following robot you need at least 2-3 sensors.

Here is one using 2 LEDs either side of the line:
2 sensor robot

And here is a 3 sensor robot:
3 sensor robot
Notice that one LED stays on the line.

And finally a 5 sensor robot:
5 sensor robot

The following websites have good step by step guides where they explain the various techniques:

• https://www.learnrobotics.org/blog/how-to-build-a-mobile-robot-using-arduino-part-4/
• https://circuitdigest.com/microcontroller-projects/line-follower-robot-using-arduino
• http://www.robotc.net/wikiarchive/Tutorials/Arduino_Projects/Mobile_Robotics/VEX/Using_the_line_tracker_to_follow_a_line

When I made my line following robot I used 2 of the following sensor:
IR sensor

These sensors were great as they pointed in towards each other, making a focal point. You can do this to your sensor by bending the LEDs slightly towards each other.

Answer 2

For obstacle detection you would usually use a different IR sensor, yes. The IR sensors usually used for line following only work at a very short range (typically <1cm). For a robot detecting obstacles you want a sensor that detects an obstacle further away, say at a 30-60 cm distance, so the robot can evade the obstacle before it runs into it.

Common IR sensors for obstacle detection look like this: Infrared distance sensor

The IR sensor you showed probably send a 0V or 5V, true or false value to a digital input of your arduino. The IR distance sensor shown above sends an analogue value (range 0-5v) to an analogue input of an arduino. They come in different ranges. Ranges go from ± 10 cm to ±5m (rough indication).

But personally I prefer to use the common HC-SR04 ultrasonic distance sensor instead of infrared ones. They have a larger usable range, a less noisy signal and detect more different types of objects. That's my personal experience from side-by-side comparison. HC-SR04

I'm reluctant to mention online shops on where to buy them. They're very common sensors.