Robot Bumper System

In my design class we have to build a functional robot. This robot must navigate the course by light sensors. I am having an issue writting the code for the bumper system though. I've become pretty confused and could use some guidance. We were provided with the skeleton of the code, but filling in the missing pieces is proving to be a challenge. Any help is greatly appreciated. BTW: I am using high tide to write my program.

You couldn't have been much less specific if you tried. We have no code, no hardware description (I assume PIC?), no schematics, no description of how the bumper system is supposed to work and no description of how the bumper system is currently working incorrectly or not working at all. We're going to need lots more good, specific information to help you, so lets see it.

Ummmmmmmmmmmmm.... ERRRRRRRRRRRRR.....ARGGGGGGGGGGGGG....

Nope... crystal ball just isn't connecting....

Code:

position = getcurrentposition();
if( position == lastposition && isdriving() )
{
    /* we ran into something */
    reversedirection();
}
else
{
    lastposition = position;
}

There. You didn't actually care if you smash into something right? What's the point of even having a bumper if you can't use it to bump into things?


Quzah.

> reversedirection();

Why not left or right ?

Reverse would result in going to and forth between two obstacles, whereas left/right would make it able to navigate a 2d maze , without other controls .

Originally Posted by manasij7479

> reversedirection();

Why not left or right ?

Reverse would result in going to and forth between two obstacles, whereas left/right would make it able to navigate a 2d maze , without other controls .

It depends if they have tank treads or not. A tank can independently control its treads, and while basically sitting still, can turn in a circle.

A car can't.

Also, it depends what they get stuck on:

Code:

___
|^

If the car is the caret, and you drive right up to the corner, a left turn grinds you up against the corner, and a right turn backing up also runs you into the wall.


Quzah.

Originally Posted by quzah

A car can't.

Oh.. didn't consider that.

Also, it depends what they get stuck on.

Aren't the sensors supposed to stop it from making foolish decisions about which way to turn ?

Originally Posted by manasij7479

Aren't the sensors supposed to stop it from making foolish decisions about which way to turn ?

Your guess is as good as mine.


Quzah.

hey, sorry for lack of information. I'm really knew to programming so this is all a bit hazy for me. I am operating on a 　
PIC16F877A microprocessor. The skeleton of the code:

Code:

void interrupt isr (void) 


// This function will be automatically called upon an interrupt


{
if (save_data ( ) ==0) 


// If interrupt was caused by real time clock, return. If


{return;} 


// interrupt was caused by bumper, save function variables


// being used by main() so they can be restored upon returning
// from interrupt.


pause (5); 


// Pause 5 msec to allow for bumper switch contact bounce


if ((PORTB & 0x01) == 1) 


// Confirm valid bumper interrupt


{
INTF = 0;
restore_data ( ); 


//Restore function variables used in main()


return;
}
output_low ('c', 0); 


//STOP the Motors! I’ve bumped into something.


output_low ('c', 5);
output_low ('c', 3);
output_low ('c', 4);
pause (50); 


//Always allow some time (50ms) for the motors to stop


/*YOUR CODE GOES HERE - I.e., Check which
bumper(s) hit and take evasive motor action. SEE
IMPORTANT NOTES BELOW */


if ((PORTB & 0x01) == 1) 


// If all bumpers have cleared their obstacles


{
INTF = 0; 


// Clear interrupt flag bit


}
restore_data ( ); 


//Restore function variables used in main()


return;


}

Photo of the pic board:
Attachment 10976


I'm not asking for you guys to completely write this program for me. I want to learn how to do this myself but would really appreciate some guidance. I have no programming experience so all imput would be great! so far i've figured out how to make the robot move and how to program led lights to blink. I'm stuck here on the bumpers though.

the purpose of the bumpers is for the robot to be able to navigate through a course. For example: if the left bumper were to be hit, i'd want the robot to stop, reverse a bit, spin to the right, and continue forward. i've been attempting to figure this out for a few days now but have gotten nowhere

I assume you have some code to make it go, or to make specific wheels get power or turn or the like? If not, get that first, so you can turn and drive. Once you can turn and drive, then you can figure out what bumper to check or trigger, and turn in response to bumper hits.


Quzah.