VEX Sensors Overview - Revision history

Bfeher at 20:31, 30 April 2012

2012-04-30T20:31:44Z

Bfeher at 17:02, 30 April 2012

2012-04-30T17:02:48Z

Bfeher: moved VEX: Sensors Overview to VEX Sensors Overview

2012-04-30T17:01:45Z

moved VEX: Sensors Overview to VEX Sensors Overview

Bfeher at 16:09, 8 March 2012

2012-03-08T16:09:25Z

Bfeher at 16:09, 8 March 2012

2012-03-08T16:09:04Z

Show changes

Bfeher at 16:03, 8 March 2012

2012-03-08T16:03:16Z

Bfeher: /* Analog Sensors */

2012-03-08T16:00:29Z

Analog Sensors

Bfeher: Created page with " {| style="font-family:Verdana, Genega, sans-sarif; font-size:80%;color:gray;" width="100%" cellpadding="0%" cellspacing="0" border="0" |- | ''Main >> [[VEX_Mai..."

2012-03-08T14:42:57Z

Created page with " {| style="font-family:Verdana, Genega, sans-sarif; font-size:80%;color:gray;" width="100%" cellpadding="0%" cellspacing="0" border="0" |- | ''Main >> [[VEX_Mai..."

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''[[Main_Page|Main]] >> [[VEX_Main|PIC]] >> [[VEX:_Sensors_Overview|Sensors Overview]] ''
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{| class="wikiText"
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|''For ROBOTC PIC Sensor ''functions'', check out the [[VEX:_Functions_-_Sensors|PIC Sensor Functions]] page!''
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|style="vertical-align:top"| __TOC__
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== Analog Sensors ==
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|There are 5 main types of Analog Sensors for the VEX CORTEX:
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=== Light ===
[[File:Vex light sensor.png]]
 
The Light sensor, also known as the Reflection sensor, returns values ranging between 0 and 4095. 0 is the lightest reading and 4095 is the darkest.
 

{|
|-
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<syntaxhighlight lang="ROBOTC">
#pragma config(Sensor, in1, lightSensor, sensorReflection)
//*!!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("Light Sensor:"); // display "Light Sensor:" on the top line

setLCDPosition(1,0); // set the VEX LCD cursor the second line, first space
displayNextLCDNumber(SensorValue(lightSensor)); // display the reading of the lightSensor sensor

wait1Msec(50); // wait 50 milliseconds to help display properly
}
}
</syntaxhighlight>
|-
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=== Potentiometer ===
[[File:Vex pot.png]]
 
Returns an analog value between 0 and 4095 ''(although mechanical stops my limit the values to between 5 and 4092)''.
 

{|
|-
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<syntaxhighlight lang="ROBOTC">
#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
}
}
</syntaxhighlight>
|-
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|-
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=== Line Follower ===
[[File:vex_linefollower.png]]
 
Returns values ranging between 0 and 4095. 0 is the lightest reading and 4095 is the darkest.
 

{|
|-
|
<syntaxhighlight lang="ROBOTC">
#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
}
}
}
</syntaxhighlight>
|-
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=== Gyro ===
[[File:vex_gyro.png]]
 
As the Gyro is turned, the values it returns are in '''tenths of degrees''', positive and negative. Thus, a SensorValue of 3600 equals 360 degrees, or one full rotation. When the sensor is mounted horizontally, counter-clockwise movements will return values from 0 to -3600; clockwise movements will return values from 0 to 3600. Once the gyro completes one full revolution, the sensor value will “roll-over” to 0 by default (for example: …3597, 3598, 3599, 3600, 0, 1, 2, 3,…). To change the “roll-over” point, un-comment line 33 (from the code below) and change the value of “SensorFullCount” from 3600 to the desired value (7200, 18000, ect)

''For more information on the Gyro sensor, check out the ROBOTC blog post: [http://www.robotc.net/blog/2011/10/13/programming-the-vex-gyro-in-robotc/ Programming the VEX Gyro in ROBOTC].''
 

{|
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<syntaxhighlight lang="ROBOTC">
#pragma config(Motor, port2, rightMotor, tmotorNormal, openLoop)
#pragma config(Motor, port3, leftMotor, tmotorNormal, openLoop, reversed)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//

/*+++++++++++++++++++++++++++++++++++++++++++++| Notes |++++++++++++++++++++++++++++++++++++++++++++
Gyro Based Turns - Basic
-This program instructs your robot to turn for the specified number of degrees in "degrees10".
-For best sensor results, clear out the gyro and manually configure it at the begging of the code.
-The Gyro is configured by default to provide values from 0 to -3600 for clockwise rotation,
and 0 to 3600 for counter-clockwise rotation

Robot Model(s): Swervebot

[I/O Port] [Name] [Type] [Description]
Motor Port 2 rightMotor VEX Motor Right side motor
Motor Port 3 leftMotor VEX Motor Left side motor
Analog Port 8 in8 VEX Gyro Top-center mounted,
away from the Cortex
--------------------------------------------------------------------------------------------------*/

task main()
{
//Completely clear out any previous sensor readings by setting the port to "sensorNone"
SensorType[in8] = sensorNone;
wait1Msec(1000);
//Reconfigure Analog Port 8 as a Gyro sensor and allow time for ROBOTC to calibrate it
SensorType[in8] = sensorGyro;
wait1Msec(2000);

//Adjust SensorScale to correct the scaling for your gyro
//SensorScale[in8] = 260;
//Adjust SensorFullCount to set the "rollover" point. 3600 sets the rollover point to +/-3600
//SensorFullCount[in8] = 3600;

//Specify the number of degrees for the robot to turn (1 degree = 10, or 900 = 90 degrees)
int degrees10 = 900;

//While the absolute value of the gyro is less than the desired rotation...
while(abs(SensorValue[in8]) < degrees10)
{
//...continue turning
motor[rightMotor] = 25;
motor[leftMotor] = -25;
}

//Brief brake to stop some drift
motor[rightMotor] = -5;
motor[leftMotor] = 5;
wait1Msec(250);
}
</syntaxhighlight>
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=== Accelerometer ===
[[File:vex_accel.png]]
 
Returns an analog value between 0 and 4095. Each Accelerometer Sensor has 3 cables, X, Y, and Z. The ports you attach them to don't have to be in any particular order ''(however you WILL need to use 3 ports)''.
 

{|
|-
|
<syntaxhighlight lang="ROBOTC">
#pragma config(Sensor, in1, xAxis, sensorAccelerometer)
#pragma config(Sensor, in2, yAxis, sensorAccelerometer)
#pragma config(Sensor, in3, zAxis, sensorAccelerometer)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//

task main()
{
int nBiasValues[3];

int X_Accel;
int Y_Accel;
int Z_Accel;

wait1Msec(500); // bias values are being calculated

/* store the bias values in an array so that they can be
* displayed in the ROBOTC global variables debug window */
nBiasValues[0] = SensorBias[xAxis];
nBiasValues[1] = SensorBias[yAxis];
nBiasValues[2] = SensorBias[zAxis];

while(true)
{
/* also store the actual sensor values so that they can be
* easily displayed in the ROBOTC global variables debug window */
X_Accel = SensorValue[xAxis];
Y_Accel = SensorValue[yAxis];
Z_Accel = SensorValue[zAxis];

wait1Msec(100);
}
}
</syntaxhighlight>
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-''[[Main_Page|Main]] >> [[VEX_Main|PIC]] >> [[VEX:_Sensors_Overview|Sensors Overview]] ''
-|-
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-{|
+{{tl|1|}}
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@@ Line 8: / Line 8: @@
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-{| class="wikiText"
+{|
 |-
-|''For ROBOTC PIC Sensor ''functions'', check out the [[VEX:_Functions_-_Sensors|PIC Sensor Functions]] page!''<br />
+|''For ROBOTC PIC Sensor ''functions'', check out the [[VEX_Functions_Sensors|PIC Sensor Functions]] page!''<br />
 <br />

@@ Line 11: / Line 11: @@
 |-
 |''For ROBOTC PIC Sensor ''functions'', check out the [[VEX:_Functions_-_Sensors|PIC Sensor Functions]] page!''<br />
 The VEX is equipped with 16 sensor ports. These can be either analog (e.g. voltage level from a photocell detecting light intensity) or digital (e.g. a touch or switch sensor).  Analog sensors should be connected to lower numbers ports and digital sensors connected to higher numbered ports. This is restriction in the VEX hardware where analog sensors are assigned ports 1 to N where N is the total number of ports.<br />

@@ Line 31: / Line 31: @@
 [[File:Vex light sensor.png]]
 <br />
-The Light sensor, also known as the Reflection sensor, returns values ranging between 0 and 4095.  0 is the lightest reading and 4095 is the darkest.
+The Light sensor, also known as the Reflection sensor, returns values ranging between 0 and 1023.  0 is the lightest reading and 1023 is the darkest.
 <br />
@@ Line 69: / Line 69: @@
 [[File:Vex pot.png]]
 <br />
-Returns an analog value between 0 and 4095 ''(although mechanical stops my limit the values to between 5 and 4092)''.
+Returns an analog value between 0 and 1023 ''(although mechanical stops my limit the values to between 5 and 4092)''.
 <br />
@@ Line 106: / Line 106: @@
 [[File:vex_linefollower.png]]
 <br />
-Returns values ranging between 0 and 4095.  0 is the lightest reading and 4095 is the darkest.
+Returns values ranging between 0 and 1023.  0 is the lightest reading and 1023 is the darkest.
 <br />
@@ Line 171: / Line 171: @@
 Motor Port 3 leftMotor VEX Motor Left side motor
 Analog Port 8 in8 VEX Gyro Top-center mounted,
-away from the Cortex
+away from the PIC
 --------------------------------------------------------------------------------------------------*/
@@ Line 213: / Line 213: @@
 [[File:vex_accel.png]]
 <br />
-Returns an analog value between 0 and 4095.  Each Accelerometer Sensor has 3 cables, X, Y, and Z.  The ports you attach them to don't have to be in any particular order ''(however you WILL need to use 3 ports)''.
+Returns an analog value between 0 and 1023.  Each Accelerometer Sensor has 3 cables, X, Y, and Z.  The ports you attach them to don't have to be in any particular order ''(however you WILL need to use 3 ports)''.
 <br />

@@ Line 25: / Line 25: @@
 {| style="font-family:Verdana, Geneva, sans-serif; color:black; background-color:#FFFFFF; text-align:left; font-size:100%;" width="100%" cellpadding="5%" cellspacing="0" border="0"
 |-
-|There are 5 main types of Analog Sensors for the VEX CORTEX:
+|There are 5 main types of Analog Sensors for the VEX PIC:
 |-
+|