Help with line following robot

Thread Starter

chaithanyatkm

Joined Aug 26, 2011
23
hi i'm new to this site. could anyone please help me with a line tracer. we will have to make one.i'm doing b.tech in electronics and communication.. this line tracer is actually a robot ( or a machine) that should follow a particular line by sensing the reflected light. it should have a lidght source at its bottom and a light detector also.. and we are told that the path will have white track on a black background. so we are thinking that light wont be reflected back from a black surface and maximum intensity will get reflected back from a white source. will that idea work??:confused: i dont know anything about this. :( anyone having any new ideas
 

praondevou

Joined Jul 9, 2011
2,942
hi i'm new to this site. could anyone please help me with a line tracer. we will have to make one.i'm doing b.tech in electronics and communication.. this line tracer is actually a robot ( or a machine) that should follow a particular line by sensing the reflected light. it should have a lidght source at its bottom and a light detector also.. and we are told that the path will have white track on a black background. so we are thinking that light wont be reflected back from a black surface and maximum intensity will get reflected back from a white source. will that idea work??:confused: i dont know anything about this. :( anyone having any new ideas
Please open a new thread.
 

Sparky49

Joined Jul 16, 2011
833
Personally, I think it would be easier to have a shiny surface with a black line.

Have two light sensors which control their own motor on the left and right side of the robot.

If the sensor detects less reflected light, then it slows down or stops its motor. Otherwise it keeps its motor going.
 

strantor

Joined Oct 3, 2010
5,329
This is a pretty common project so you can probably find something online like a tutorial. I've never done it myself, so my first thought is along the lines of sparky's; however (having never done it) I couldn't predict how smoothly it would operate with such simple control; you may need some proportional control. big picture: 2 sensors mounted side-by-side. if both detect the line (i.e. absence of reflected light) then it knows it's on track. if the line is detected by both sensors and the it transitions to the line being only detected by the right sensor, then it knows that it is going off track to the left and needs to turn right, and vise versa. You may be able to gain more control by using 3 sensors. if line is detected by middle sensor, you are on track; if detected by middle & right, steer slight right; if detected by right sensor only, steer hard right. My first instinct would be to use a microcontroller for this logic, but someone around here may be able to tell you how to do it otherwise.
 

Sparky49

Joined Jul 16, 2011
833
If you buy the book;

Electronics Projects for Dummies

It has the exact circuit diagram for what I described.


I won't put it on here, because that would be cheating the authors.
 

strantor

Joined Oct 3, 2010
5,329
So it's confirmed that it can work as you described it. I've just been reading up on it and apparently there are line-following robot competitions. I guess that would lead to designs at both ends of the spectrum from super simple to over complicated. Some may perform better than others, while some may be more efficient than others. This build notes page pretty much describes what I described (except he's using 5 sensors instead of 2 or 3 and he's using a PIC):
 

Thread Starter

chaithanyatkm

Joined Aug 26, 2011
23
can we make the idea more creative than just making a robot to follow a line. Like, can we think of a dog shaped robo which will move towards a place by seeing light, or in the shape of a watchman who will move towards a place by hearing a sound. Just ideas are enough, as they(heads) won't ask us to explain this time. we are just told to bring ideas..
 
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