need help

[bishooooy]

hi
am in my last year engineering faculty and i choosed my project to be aline followe robot
i thought to purchase acar (toy) with a remote control and supress the rf reciever and connect my own control circuit(with micro controler 8051)
but am having aproblem cause the speed of the dc motor is tooo high
so it turns after the turn not at the turn
so what can ido
do i change my program(can you help)
do i contro the spreed of dc motor?(how)
do i change dc motor with steper?
thank you so much

[franklin97355]

Depending on where you hacked into the control of the car you could try using PWM with a low duty cycle to slow the car or power it in short spurts and do your tests while it is stopped. Not the most efficient but it might do in a pinch.

[HarryBotter]

I've tried doing this with poor results. The best way to do this is to add your own motor controller and then control speed with PWM using your chip.

Harry

[bishooooy]

hi
thanks all for your concern and replying
dear mr.harry
am already controlling the motor with my own controller circuit using 8051 micro controller
+can you help me where to get information about this pwm speed control
+can you help me with the main idea of the microcontroller program
my current is something like that:
*am using 3 sensor-emitter pairs amiddle,right and left one
*if the left see the line i send pulse to turn left and vise versa
thats all
should the programm include some more things
+is there any usefull web pages that can help
many thanks

[HarryBotter]

There is so much information on the internet that it shouldn't be very difficult to find what you need. Just do a Google search with the words PWM , 8051 or line following robot and you'll find lots. Here is a sample:

http://www.datadog.com/pwm_tutorial.pdf
http://www.kmitl.ac.th/~kswichit%20/ROBOT/Follower.pdf
http://www.robotroom.com/Sandwich.html

Harry

[MerlinsWand]

hi
am in my last year engineering faculty and i choosed my project to be aline followe robot
i thought to purchase acar (toy) with a remote control and supress the rf reciever and connect my own control circuit(with micro controler 8051)
but am having aproblem cause the speed of the dc motor is tooo high
so it turns after the turn not at the turn
so what can ido
do i change my program(can you help)
do i contro the spreed of dc motor?(how)
do i change dc motor with steper?
thank you so much



Yeah. I can see how that might be a problem. I'm not sure there's a simple solution.

[shimniok]

Throwing out a wild thought... and I may be "full of it" here :)

Maybe you should drive the car backwards instead? So that the turning wheels are in back. (In addition to PWM to lower speed).

First, you'll get much quicker turning response. Second, the sensors can be places far ahead of the turning wheels, so that when the vehicle detects a turn in the line, it'll be able to quickly adjust course.

Just tossing out this idea in case it helps. Best of luck!

Michael