Difference between revisions of "The Use of Light Sensor"

Outline

Microduino-Light adopts photosensitive resistor. It uses a resistor that is based on semiconductor's photoelectric effect and is able to change along with the intensity of t the incident light. The photosensitive resistor is generally applied in light measurement, light control and photoelectric conversion.

Specification

• Electrical features
  • The brighter the light is, the bigger the output voltage gets.
  • Output analog quantity
• Tech parameter
  • Bright Resistance(10Lux): 8-20KΩ
  • Dark Resistance: 1MΩ
  • Sensitivity: Under the light of 10Lux and 100Lux, the resistance rate is (R10/R100) =0.8
• Size
  • Size of the Board: 20mm*10mm
  • 1.27mm-pitch 4Pin interface;
• Connection method
  • Pin Description: GND, VCC, signal and NC. It needs analog port（A0-A7）to detect.

Development

Equipment

• Other Hardware Equipment
  • One USB cable

Preparation

• Setup 1：Connect Microduino-Light and the A0 analog port of the Hub.

• Setup 2：Connect the CoreUSB, Hub and Light to the computer with a USB cable.

Experiment: Detect analog Brightness Value

• Open Arduino IDE and copy the following code into IDE.

#define  sensorPin  A0

int state;

void setup()
{
  pinMode(sensorPin, INPUT);
  Serial.begin(9600);
}
void loop()
{
  state = analogRead(sensorPin);
  Serial.print("state:");
  Serial.println(state);
  delay(100);
}

• Select the right board from Tools→Serial Port in Arduino IDE and download the program.
  
• After the download, you can open the serial monitor. The displayed value reflects the current light intensity.

• Result

The stronger the light is, the greater the output value becomes. Therefore, you can build some projects controlled by light intensity change.

Program Debugging

• “#define sensorPin A0”defines sensor interface.
• Use“analogRead(sensorPin);”function to read the output analog value of the sensor and therefore, to judge light intensity change.

Application

• Light-control street lamp

Video