Hardware Reference
In-Depth Information
Machine-vision-based line following robot
The inal alternaive to a sensor to build a line following robot is a camera. The Raspberry Pi
foundaion has released its own camera module and it is also simple to interface.
A line following robot can be implemented by grabbing a frame from the camera module
and convering it into a grayscale image. The grayscale image can be used to determine the
current posiion of the robot with respect to the line that has to be followed. Since white
and grey surfaces have varying levels of grey colour, the orientaion of the robot can be
corrected using a diferenial steering mechanism.
A camera would be overkill for building a line following robot to just follow a black line
on a white surface in an indoor environment (also, a bit overwhelming for a beginner).
However, we can use it out of an academic interest.
Sensor selection
We have discussed the diferent sensing opions available for building a line following robot.
We will choose the infrared sensor. We chose the infrared sensor for the following reasons:
F
It can be used only in controlled lighing condiions (since we are using an
unmodulated infrared light source) but serves as a good start for a beginner
F
It is readily available and easy to interface
F
It has a disinct edge over light detecing resistors since it has a beter response ime
Objective complete - mission debriefing
In this task, we discussed the diferent sensor opions available for a line following robot.
Implementation of line following
logic based on sensor data
In this task, we will implement a simple line following technique using the infrared sensor.
We will make use of a pair of infrared sensors to track a black line on a white surface. The
robot will move forward if both the sensors are on a white surface. The robot turns left if
the left sensor is on the black line and vice versa.
Prepare for lift off
The sensor needs to be soldered and connected to the Raspberry Pi (something like the one
shown in the preceding schemaic). Alternaively, you may use a sensor of your choice.
