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Topic: Grove UV Sensor (Read 173 times) previous topic - next topic

Marciokoko

Im using the UV sensor from Grove, data here:

http://www.seeedstudio.com/wiki/Grove_-_UV_Sensor


In this document the Grove states that:

"wide spectral range of 200nm-400nm. The module outputs electrical signal which varies with the UV intensity, which gives your suggestion if it is a good idea to beach today‚Äč"

So basically the sensor returns mV which using this equation:

illumination intensity = 307 * Vsig

can be converted to illumination intensity in mW/m2.  The Grove goes on to reference the EPA UV Index measurement which can be 'roughly estimated' using this conversion:

UV Index = illumination intensity / 200

But what I am getting is, for example, 500 on average with occasional peaks of 1,500 for UVIndex according to this sketch:

Code: [Select]
void setup(){
 
  Serial.begin(9600);
}
 
void loop(){ 
  int sensorValue;
  long  sum=0;
  for(int i=0;i<1024;i++)
   { 
      sensorValue=analogRead(A0);
      sum=sensorValue+sum;
      delay(2);
   }   
 sum = sum >> 10;
 Serial.print("The voltage value:");
 Serial.print(sum*4980.0/1023.0); // This gives mV according to Grove
 Serial.println("mV");
 delay(20);
 Serial.print("\n");
 
 delay(20);

 Serial.print("UVIndex is: ");
 uvindex = (307*(sum*4980.0/1023.0))/200; // This would be the equivalent UVIndex
 Serial.println(uvindex);
 Serial.print("\n");
}


It seems way off (values of 500 for uvindex) versus the 0-11+ scale the EPA uses even though it is referenced in the document.  Has anyone worked with this sensor?

TomGeorge

Hi,
Have you sat down with a calculator and used it to do the program calcs?

Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....

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