PIC16F877A - Is it possible ? Kindly read and help .- Urgent

This is my idea .
I`m planning to use a PIC16F877A to make a line follower . I want my line follower to have the feature of saving the path last travelled into memory and then travel in the same path when required even when there is no line to follow . Micro Experts , Kindly help me .

Re: PIC16F877A - Is it possible ? Kindly read and help .- Ur

thatsmyid said:

This is my idea .
I`m planning to use a PIC16F877A to make a line follower . I want my line follower to have the feature of saving the path last travelled into memory and then travel in the same path when required even when there is no line to follow . Micro Experts , Kindly help me .

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The problems are more mechanical than software, you need some way of accurately measuring the travel of the unit, then accurately retracing it.

One simple possibility is to use stepper motors, and keep a count of the number of steps for each motor, with seperate counts for each part of the path. Or you could arrange odometer readings from each wheel, and count the number of pulses.

But in either case, it won't be perfect, because there's no feedback to show if it's drifting off slightly (wheel slip, or whatever).

Thanx a million !

Hey ... thanx a million .....
But , say i`m using stepper motors(assuming that hardware has no problems) , then how do i do the required task . Kindly give a psuedocode or an algorithm for accomplishing the task . Thanx once again for the prompt reply .

Thanking you ,

Karthik

A line follower continuously calculates the trajectory to take. Maybe several times per second, the path could change. There is not enough memory to save the entire path previously taken inside a PIC16F877A. I doubt it would be useful anyway even if you could.

However, it would be enough to remember the last trajectory (direction and speed) before the line tracking signal is lost. The next trajectory can depend on the current trajectory as well as the calculated trajectory from the tracking signal (sort of like PID control).