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[on:]

Hello, I'm trying to get a motor to stop when my light sensor reads a black line. I'm also trying to have a screen display the value of the light sensor in real time. I'm using a dfrobot motor controller, SFE light sensor, and a Grove LCD. I have tested all the parts by themselves, and they work fine so I know I'm doing my program wrong. The program, no matter the value of the light sensor, always choses loop #2. I have no idea why. Any help would be appreciated.

Code:

#include <SerialLCD.h>
#if ARDUINO < 100
#include <NewSoftSerial.h> //this is a must
#else
#include <SoftwareSerial.h>
#endif

SerialLCD slcd(11,12);
int E2 = 5;                         
int M2 = 4;   
int sensorPin = A1;
int long sensorValue = 0;
int value = 250;
int value2 = 0;


void setup()
{

    pinMode(M2, OUTPUT);
    slcd.begin();
}

void loop()
{
  sensorValue = analogRead(sensorPin);

  while (sensorValue > 1050) {  // #1
   
  sensorValue = analogRead(sensorPin);
 
  slcd.setCursor(0, 1);
  slcd.print(sensorValue, DEC);
   
  digitalWrite(M2,HIGH);       
  analogWrite(E2, value);
   
  }
 
 
 
 while (sensorValue < 1050) {  // #2
   
    sensorValue = analogRead(sensorPin);
   
    slcd.setCursor(0, 1);
    slcd.print(sensorValue, DEC);
   
    digitalWrite(M2,HIGH);     
    analogWrite(E2, value2);   //PWM Speed Control
   
 }}

[Reply #1 on:]

The maximum value from analogRead() is 1023 so it will ALWAYS be less than 1050.

[Reply #2 on:]

Good example of when it's useful to use Serial.print to send the value to the monitor for debugging....

[Reply #3 on:]

Good example of when it's useful to use Serial.print to send the value to the monitor for debugging....

And/or read the documentation for the functions being used.

[Reply #4 on:]

Are you sure about the value?

When the program starts up the light sensor reads 950, but once you move the sensor over black (or any other color than what it started on) the LCD displays bright as 9,500-9,900 and dark as 1011.

Any ideas?

Thanks,
Drew

[Reply #5 on:]

Also I'm not using Serial.print as the lcd is telling me the value.

[Reply #6 on:]

the LCD displays bright as 9,500-9,900

I'd suggest it reads "95", with a couple of leftover zeroes.
Yes, we're really sure about the analogRead.

Also I'm not using Serial.print as the lcd is telling me the value.

Which is why you should use debugged, well-understood methods to do your debug.

[Reply #7 on:]

the LCD displays bright as 9,500-9,900 and dark as 1011.

I'm pretty sure that if you printed the value correctly on the LCD, it would show 950 to 990. But, without seeing your code...

[Reply #8 on:]

Code:

int long sensorValue = 0;

is it int or long or both?
Arduino will be mad...

[Reply #9 on:]

Arduino will be mad...

You sure about that?
Don't knock it until you've tried it   

[Reply #10 on:]

Hi,
I think he must clear his LCD... I dont know whether his sketch may include  Lcd.clear() sort of function just next to the both of while loop or before printing any value..
1050 is strange... the first while loop will never work..

[Reply #11 on:]

Thanks for all of your help. I should have tried the Serial.print from the beginning. The problem was that the lcd left the 0 from 1000 so it made it seem like the light sensor was reading 9900 when it was really 990.  I was able to adjust the values and it works now.

Thanks,
Drew

Code:

#include <SerialLCD.h>
#if ARDUINO < 100
#include <NewSoftSerial.h> //this is a must
#else
#include <SoftwareSerial.h>
#endif

SerialLCD slcd(11,12);
int E2 = 5;                         
int M2 = 4;   
int sensorPin = A1;
int long sensorValue = 0;
int value = 250;
int value2 = 0;


void setup()
{

    pinMode(M2, OUTPUT);
    slcd.begin();
}

void loop()
{
 
 
  sensorValue = analogRead(sensorPin);
 
  while (sensorValue < 1000) {  // #1
   
  sensorValue = analogRead(sensorPin);
 
  slcd.setCursor(0, 1);
  slcd.print(sensorValue, DEC);
   
  digitalWrite(M2,LOW);       
  analogWrite(E2, value);
   
  }
 
 
 
 while (sensorValue > 1000) {  // #2
   
    sensorValue = analogRead(sensorPin);
   
    slcd.setCursor(0, 1);
    slcd.print(sensorValue, DEC);
   
    digitalWrite(M2,HIGH);     
    analogWrite(E2, value2);   //PWM Speed Control
   
 }}

[Reply #12 on:]

I bit, this guy will comeback again.. He is like a pigeon, when the   come near the pigeon ,he closes his eyes.. You solve the problem not hide it...
Okay, just try:

Code:

#include <SerialLCD.h>
#if ARDUINO < 100
#include <NewSoftSerial.h> //this is a must
#else
#include <SoftwareSerial.h>
#endif

SerialLCD slcd(11,12);
int E2 = 5;                         
int M2 = 4;   
int sensorPin = A1;
int sensorValue = 0;
int value = 250;
int value2 = 0;


void setup()
{

    pinMode(M2, OUTPUT);
    slcd.begin();
}

void loop()
{
 
 
  sensorValue = analogRead(sensorPin);
 
  while (sensorValue < 1023) {  // #1
   
  sensorValue = analogRead(sensorPin);
  slcd.clear();
  slcd.setCursor(0, 1);
  slcd.print(sensorValue, DEC);
   
  digitalWrite(M2,LOW);       
  analogWrite(E2, value);
   
  }
 
 
 
 while (sensorValue > 1023) {  // #2
   
    sensorValue = analogRead(sensorPin);
     slcd.clear();
    slcd.setCursor(0, 1);
    slcd.print(sensorValue, DEC);
   
    digitalWrite(M2,HIGH);     
    analogWrite(E2, value2);   //PWM Speed Control
   
 }}