Example Code for Arduino-Ambient Light (UART 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

UART Connection Diagram

Other Preparation Work

Note: Select I2C or UART mode by DIP switch.

Sample Code

UART Mode

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

#include "DFRobot_LTR390UV.h"
#include <SoftwareSerial.h>
#define UARTMODE //UART mode

SoftwareSerial mySerial(/*rx =*/4, /*tx =*/5);
DFRobot_LTR390UV ltr390(/*addr =*/LTR390UV_DEVICE_ADDR, /*s =*/&mySerial);

void setup()
{
  #define UARTMODE
  mySerial.begin(9600);
  Serial.begin(115200);
  while(ltr390.begin() != 0){
    Serial.println(" Sensor initialize failed!!");
    delay(1000);
  }![SEN0540-UART mode obtains ambient light results](https://dfimg.dfrobot.com/62fba4cb025a892c98c6da64/wikien/e032889330d221bc2c3afb65d48f9bc9.png "SEN0540-UART mode obtains ambient light results")
  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 the 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(100);
}

Result

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

Additional Information

Note: Ambient Light Reference Range