View Full Version : sensor placement

01-26-2011, 11:21 PM
I had made a line follower with 4 sensors, width of my track is 2.5cm

please suggest me the best place to put the sensors & what should be the distance btw sensors

01-27-2011, 12:46 AM
Look into design of 3pi robot ... it is optimized for line following and line maze solving. Look at its sensor placement.


01-28-2011, 08:54 AM
Put your sensors as far as possible from your pivoting wheels, it will give your controller more time to react and reduce overshooting.

The distance between the sensors will depend on your track, if there will be no discontinuities in the track, put two sensors just at the center at a distance of 2 - 2.5 cm. This way you can sense discontinuities in track, by knowing the values of these two sensors. Put the other two sensors as wide as possible.

You will have to experiment with the sensor placement. Putting them too close to the center of the robot, will increase overshooting of the line and putting them wide part will result in rough zig-zag movements abount the line. Get the best placement from trial and error.

01-28-2011, 09:48 PM
thank pratheek

in my track i have both discontinuities & death end

in both case my sensor detects white color so how to differentiate b/w them

01-29-2011, 09:34 AM
Place two sensors at the center at a distance of around 2cm such that both of them sense the line when the robot is aligned straight with the line. When their is a discontinuity in the track, both the center sensors will not be detecting the line and you know that there was a discontinuity.

It might seem simple, but implementing this practically and getting the right result every time, is a little tough because there are many other situations where the center sensors will lose the line simultaneously other than in places where there are discontinuities in the line. You will have to make use of your other two sensors to tackle this.