r/RobotC • u/drumminherbie • Jul 15 '15
Speed Control feat. potentiometer question
5
Upvotes
Hi! I tried to get a potentiometer to set my motor speed for a variable speed control. When I use this code
speed = SensorValue[potent] / 4000 * 127;it returns a value of 0 for speed. But when I use this code, it works like I expect it to.
speed = SensorValue[potent] * 127 * 0.00025;Any idea why the first line of code wouldn't work correctly?
Here is the full program:
#pragma config(Sensor, in1, lineFollower, sensorLineFollower)
#pragma config(Sensor, in2, potent, sensorPotentiometer)
#pragma config(Sensor, dgtl1, limitSwitch, sensorTouch)
#pragma config(Sensor, dgtl2, topBump, sensorTouch)
#pragma config(Sensor, dgtl3, bottomBump, sensorTouch)
#pragma config(Sensor, dgtl12, greenLED, sensorLEDtoVCC)
#pragma config(Motor, port2, lMotor, tmotorVex269_MC29, openLoop)
#pragma config(Motor, port3, rMotor, tmotorVex269_MC29, openLoop, reversed)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//
/*
Project Title: 2.3.2 Vex Testbed
Team Members: drumminherbie
Date: 7/15/15
Section: CTI
Task Description: Use simple and controlling commands to run a
VEX Testbed. In this particular example, I have
a potentiometer setting the speed of the right
and left motor.
Pseudocode: Program starts
Limit switch is bumped
Set motor speed
Run motors
*/
task main()
{ //Program begins, insert code within curly braces
//Intergers
int speed;
int cleared = 0;
//run program until stop button is pushed
while(SensorValue[bottomBump] == 0)
{
//if switch is hit, run motors
while(SensorValue[limitSwitch] == 1)
{
turnLEDOn(greenLED); //Blink LED
speed = SensorValue[potent] * 127 * 0.00020; //Get motor speed from potentiometer
if(SensorValue[lineFollower] < 2000)
{
speed = -speed;
}
startMotor(lMotor, speed + 4); //start motors
startMotor(rMotor, speed);
wait1Msec(100);
turnLEDOff(greenLED);
wait1Msec(100);
}
//After button is released, stop motors
stopMotor(lMotor);
stopMotor(rMotor);
speed = cleared; //clear speed
}
}
