VEX2 Sensors Overview

Main >> CORTEX >> Sensors Overview

For ROBOTC CORTEX Sensor functions, check out the CORTEX Sensor Functions page!

The VEX 2.0 Cortex is equipped with 20 sensor ports. There are 8 Analog Sensor Ports and 12 Digital Sensor Ports. Note that unlike the VEX - PIC microcontroller, all Analog sensors must be in Analog ports, while all Digital sensors must be in Digital ports. There are a variety of functions and variables used for configuring these ports and accessing their values. Configuring sensors can be complicated. ROBOTC has a built-in wizard that can be used to configure the VEX 2.0 Cortex sensors. The wizard contains a number of PC windows that allow you to set the following fields for the sensor: The variable name that you want to assign to the sensor. Using a name like “leftBumper” makes for a more readable program than 'dgtl3'! The port that the sensor is connected to. The type of sensor – touch, quadrature encoder, sonar, line follower, etc.

Analog Sensors

There are 5 main types of Analog Sensors for the VEX CORTEX:

Line Follower The Line Follower sensor, also known as the Reflection sensor, returns values ranging between 0 and 4095. 0 is the lightest reading and 4095 is the darkest. #pragma config(Sensor, in1, lineFollower, sensorLineFollower) //*!!Code automatically generated by 'ROBOTC' configuration wizard  !!*//   task main { wait1Msec(2000); // wait 2 seconds before exectuing following code bMotorReflected[port2] = true; // reflects direction of motor on port 2   while(true) // infinite loop: { if(SensorValue(lineFollower) < 950) // if the lineFollower sensor reads a value less than 950: { // turn left: motor[port2] = 50; // motor on port 2 is run at power level 50 motor[port3] = 0; // motor on port 3 is stopped at power level 0 } else // lineFollower sensor reads a value greater than or equal to 950: { motor[port2] = 0; // motor on port 2 is stopped at power level 0 motor[port3] = 50; // motor on port 3 is run at power level 50 } } }

Potentiometer Returns an analog value between 0 and 4095 (although mechanical stops my limit the values to between 5 and 4092). #pragma config(Sensor, in1, potentiometer, sensorPotentiometer) //*!!Code automatically generated by 'ROBOTC' configuration wizard  !!*//   task main { wait1Msec(2000); // wait 2 seconds before exectuing following code bMotorReflected[port2] = true; // reflects direction of motor on port 2   while(true) // infinite loop: { clearLCDLine(0); // clear the top VEX LCD line clearLCDLine(1); // clear the bottom VEX LCD line   setLCDPosition(0,0); // set the VEX LCD cursor the first line, first space displayNextLCDString("Potentiometer:"); // display "Potentiometer:" on the top line   setLCDPosition(1,0); //set the VEX LCD cursor the second line, first space displayNextLCDNumber(SensorValue(potentiometer)); // display the reading of the potentiometer sensor   wait1Msec(50); // wait 50 milliseconds to help display properly } }

Line Follower

Gyro

Accelerometer

#pragma config(Sensor, S1, touchSensor, sensorTouch) //*!!Code automatically generated by 'ROBOTC' configuration wizard  !!*//   task main() { while(SensorValue(touchSensor) == 0) // while the Touch Sensor is inactive (hasn't been pressed): { // DO NOTHING (wait for press) } while(SensorValue(touchSensor) == 1) // while the Touch Sensor is active (pressed): { // DO NOTHING (wait for release) }   // YOUR CODE GOES HERE // otherwise (the touch sensor has been activated [pressed] ): motor[motorB] = 75; /* run motors B and C forwards */ motor[motorC] = 75; /* with a power level of 75 */ wait1Msec(1000); // wait 1000 milliseconds (1 second) before moving to further code }