Question about line following again.....

[robotboy]

Hi, I'm new to this forum and I've a few question to ask you all......

1. For line following robot, usually the sensors will be put at the front of the driving wheel, right?(I'm using differential drive). So is it possible to put the sensors behind the wheel?Anyone can tell me the algorithm?

2. When I tested my line following robot without connecting the motor,(i just test the algorithm using LED), the robot work fine and it follow what i want. But when i connect it to the motor, the robot become crazy and out of control. I know that's because of the noise that generated by the motor, but i use 2 separated battery for the robot, 1 sets for electronic and 1 sets for motor. They are not connected except they are common grounded. So, any solution to this problem?

3. If we want to control a stepper motor, we need to send pulses to the driver right? so is it any IC that can generate the pulse and i can control the speed on the fly?I'm using PIC16F877A and i dont want to write a program with delay to generate the pulse. During startup of the stepper, i want to ramp up the speed from 0 to its maximum speed....

I really hope that anyone can answer my question....thanks a lot

 

[JFDuval]

Hi!

Putting two set of battery with common gnd will give you lot of parasite. You should use a chip, like a L293D, to drive you motor and opto isolate your entrances. By the way, you will have two ground and less parasites. Good luck,

 

[falleafd]

1. For line following robot, usually the sensors will be put at the front of the driving wheel, right?(I'm using differential drive). So is it possible to put the sensors behind the wheel?Anyone can tell me the algorithm?

No, put the sensor behind the wheel is not stable.

 

[ivancho]

YOu gotta try some decoupling capacitors..... make sur that you put a cap across the motor leads, as well as use a regulator with a a lot of 0.1uF Caps, also put them really close to the power supply inputs of each chip.

THe common ground make sure that is connected at the batery and not just anywhere in the boards commons... if you take the commons straigth back to the battery noise is easier to be filtered.

Ivancho

 

[robotboy]

ok, if i put the sensors in front of the driving wheel, what's the optimal distance between the sensor and the wheel?

my problem is if i put the sensor in front of the wheel, it's no problem for forward line following. But when i want to reverse and line following too, i come into trouble....so any solution besides putting another set of sensor behind the wheel?

 

[falleafd]

**broken link removed**

This should be helpful for you.

 

[falleafd]

my problem is if i put the sensor in front of the wheel, it's no problem for forward line following. But when i want to reverse and line following too, i come into trouble....so any solution besides putting another set of sensor behind the wheel?

You put 2 couple of sensors in front and behind the wheels. If you go forward, use the front sensor. If you go reverse, use the back sensors. Of course, they are the same. But they will be more stable.

goodluck

 

[arash_ele]

put a >1000uf capacitor parallel to your uC power wires. It reduces the noise.

+5v ---------------- +5v(No noise)
|+
( ) C1 (1000uf)
|-
GND --------------- GND

have fun!