Vex Light Sensor Detector

VEX V5 Technical Support UNOFFICIAL Tech Support
#1

So I am trying to build a small object detector using a light sensor with an LED pointing at it so when an object passes between them the light dims and the sensor reaches a threshold. Then some LED lights go on. This would need to be in a while loop to keep in running. Every time time I try to use it get errors like crazy.

I don’t know much about coding and this is rather confusing to me. I keep getting errors dealing with the brackets and such.

Thanks for any help given

#2

Please post code samples inside

 blocks.

Terry
#3

What errors are you getting?

#4

Usually errors relating to brackets. Like it says there is no macthing brackets but there is one.

#5

Prove it! Post your code for all the world to see. :slight_smile:

#6 
#pragma config(Sensor, in1,    lite,           sensorReflection)
#pragma config(Sensor, dgtl1,  Mlight,         sensorLEDtoVCC)
#pragma config(Sensor, dgtl2,  red,            sensorNone)
#pragma config(Sensor, dgtl3,  red2,           sensorNone)
#pragma config(Sensor, dgtl4,  green,          sensorNone)
//*!!Code automatically generated by 'ROBOTC' configuration wizard               !!*//

task main()
{
sensorValue[dgtl11] = 0;
	while{true}
		
	sensorValue[in1] > threshold;
		
		sensorValue[red] = 0;
		
		wait10Msec
		
		sensorValue[red2]
    
		sensorValue[green]
}

Here are the errors

File “C:\Users\Student.C105-10\Downloads\wrong.c” compiled on Nov 24 2014 09:18:39
Warning:Substituting similar variable ‘SensorValue’ for ‘sensorValue’. Check spelling and letter case.
Error:Missing ‘(’ before ‘{’
Warning:’;’ expected before ‘}’. Automatically inserted by compiler
Warning:Meaningless statement – no code generated
Warning:Substituting similar variable ‘SensorValue’ for ‘sensorValue’. Check spelling and letter case.
Error:Undefined variable ‘threshold’. ‘short’ assumed.
Warning:Meaningless statement – no code generated
Warning:Substituting similar variable ‘SensorValue’ for ‘sensorValue’. Check spelling and letter case.
Warning:Symbol ‘wait10Msec’ is ‘deprecated’ definition. There may be alternate symbol with equivalent functionality.
Error:Internal Compiler: Unexpected use of proc ‘wait10Msec’ in an expression
Error:Procedure ‘wait10Msec’ is invalid syntax at this point
Warning:Missing ‘;’ has been automatically inserted by compiler
Warning:Meaningless statement – no code generated
Warning:Substituting similar variable ‘SensorValue’ for ‘sensorValue’. Check spelling and letter case.
Warning:Missing ‘;’ has been automatically inserted by compiler
Warning:Meaningless statement – no code generated
Warning:Substituting similar variable ‘SensorValue’ for ‘sensorValue’. Check spelling and letter case.
Warning:’;’ expected before ‘}’. Automatically inserted by compiler
Warning:Meaningless statement – no code generated

I am at a loss with coding and I don’t have time to do all the fixing myself. Thanks to anyone who helps.

#7

a few things…

The while loop declaration is incorrect.

See the example here.
http://www.robotc.net/wiki/Tutorials/Arduino_Projects/Additional_Info/Loops


while{true}

should be like this to loop around this section forever:


while(true)
{
     /// rest of code goes here


}

Next, you use a conditional check as a statement… I am not exactly sure what you are trying to do. You can set a sensor to a specific value but you can’t tell the computer to make a value greater than another.


sensorValue[in1] > threshold;

That line should be within an if or while statement itself… Notice the brackets for when the condition trips, I go do this.


if(sensorValue[in1] > threshold)
{
     // some code that knows what I want to do when the sensor trips
}

if statements explained here:
http://www.robotc.net/wiki/Control_Structures

Next the wait is a function call and needs an argument to wait a specific number of milliseconds. You also forgot the semicolon so the compiler kept on going to the next line jamming all the text together as one line.

[

](http://www.robotc.net/wiki/VEX2_Functions_Timing)
#8

Thank you. I am trying to make a ciggarette disposal that flashes lights to reduced ciggarette littler. So that is why I need the code to always be running.

#9