We know that as we move closer to the goal our robot cannot continue to shoot balls out at the same speed or angle. We were wondering if there was anyway to create a program where a button press would allow the motor to increase or decrease in speed? As of now we are kind of short some motors so we are looking to not add an adjustable shooter to increase or decrease the angle. I use Robot.C 4.0 to program.
Here are a couple of example of how you could do this.
The first example just dedicates a button to a motor speed, Btn8U is 100, Btn8L is 75 etc.
#pragma config(Motor, port2, flyWheel, tmotorVex393_MC29, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//
task main()
{
int motorSpeed = 0;
while(1)
{
// Press one of four buttons to set motor speed
if( vexRT Btn8U ] )
motorSpeed = 100;
if( vexRT Btn8L ] )
motorSpeed = 75;
if( vexRT Btn8R ] )
motorSpeed = 50;
if( vexRT Btn8D ] )
motorSpeed = 0;
// Send to the motor
motor flyWheel ] = motorSpeed;
// Don't hog the cpu :)
wait1Msec( 25 );
}
}
The second example uses two buttons to increase or decrease the motor speed. When doing this you need to be careful to only detect the “press” and then wait for a release before detecting the next “press”. You could simply wait in a loop for that release but then the rest of your driver control code would not run (unless you used a second task for this code). This example uses a flag (just a variable that can be true or false) to save the fact that a button was pressed and check each time around the while loop to see if it has been released.
#pragma config(Motor, port2, flyWheel, tmotorVex393_MC29, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//
task main()
{
int motorSpeed = 0;
bool notPressed = true; // button is not pressed
while(1)
{
// Initial speed is 100
if( vexRT Btn8U ] )
motorSpeed = 100;
// Stop
if( vexRT Btn8D ] )
motorSpeed = 0;
// Detect 8L press
if( vexRT Btn8L ] && notPressed ) {
// Slower
motorSpeed = motorSpeed - 10;
notPressed = false;
}
// Detect 8R press
if( vexRT Btn8R ] && notPressed ) {
// Faster
motorSpeed = motorSpeed + 10;
notPressed = false;
}
// if both button are "not pressed" then set flag true
if( !vexRT Btn8L ] && !vexRT Btn8R ] )
notPressed = true;
// Limit the speed, we must not go negative or too fast
if(motorSpeed > 100)
motorSpeed = 100;
if(motorSpeed < 0)
motorSpeed = 0;
// Send to the motor
motor flyWheel ] = motorSpeed;
// Don't hog the cpu :)
wait1Msec( 25 );
}
}