Example Code for Arduino-Ambient Light (I2C Mode)

Hardware Preparation

• DFRduino UNO R3 (SKU: DFR0216) ×1
• Gravity: LTR390-UV Sensor(SKU: SEN0540) ×1
• Gravity-4P I2C/UART Sensor Cable(included with SEN0540) × 1

Software Preparation

• Download Arduino IDE: Click to Download Arduino IDE
• Download the DFRobot_LTR390UV Library: DFRobot_LTR390UV Library
• For Arduino IDE V1.8.19 (or earlier), install the library manually: How to Add a Library
• For Arduino IDE V2.0.0 (or later), directly search for the "DFRobot_LTR390UV" library in the Library Manager and install it.

Wiring Diagram

I2C Connection Diagram

Other Preparation Work

Note: Select I2C or UART mode by DIP switch.

Sample Code

I2C Mode

The function of the following code is to obtain the value of ambient light for this sensor in I2C communication mode.

#include "DFRobot_LTR390UV.h"
DFRobot_LTR390UV ltr390(/*addr = */LTR390UV_DEVICE_ADDR, /*pWire = */&Wire);

void setup()
{
  Serial.begin(115200);
  while(ltr390.begin() != 0){
    Serial.println(" Sensor initialize failed!!");
    delay(1000);
  }
  Serial.println(" Sensor  initialize success!!");
  ltr390.setALSOrUVSMeasRate(ltr390.e18bit,ltr390.e100ms);//18-bit data, sampling time of 100ms 
  ltr390.setALSOrUVSGain(ltr390.eGain3);//Gain of 3
  ltr390.setMode(ltr390.eALSMode);//Set ambient light mode 
}
void loop()
{
  float als = 0;
  als = ltr390.readALSTransformData();//Get data converted from ambient light intensity, which can only be used in ambient light mode
  Serial.print("ALS:");
  Serial.print(als);
  Serial.println("Lux");
  delay(1000);
}

Result

Serial print ambient light data (in an office with strong light).

Additional Information

Note: Ambient Light Reference Range