MSP430FR4133 LaunchPad and VEML6070 sensor example using Energia

In this example we look at an VEML6070 UV sensor and connect it to a MSP430FR4133 LaunchPad.

First a little about this sensor

VEML6070 is an advanced ultraviolet (UV) light sensor with I2C protocol interface and designed by the CMOS process. It is easily operated via a simple I2C command. The active acknowledge (ACK) feature with threshold windows setting
allows the UV sensor to send out a UVI alert message. Under a strong solar UVI condition, the smart ACK signal can be easily implemented by the software programming. VEML6070 incorporates a photodiode, amplifiers, and analog / digital circuits into a single chip. VEML6070’s adoption of FiltronTM UV technology provides the best spectral sensitivity to cover UV spectrum sensing. It has an excellent temperature compensation and a robust refresh rate setting that does not use an external RC low pass filter.

VEML6070 has linear sensitivity to solar UV light and is easily adjusted by an external resistor. Software shutdown mode is provided, which reduces power consumption to be less than 1 μA. VEML6070’s operating voltage ranges from 2.7 V to 5.5 V.

You can find out about the UV index at the following link – https://en.wikipedia.org/wiki/Ultraviolet_index

This is the key chart from this site and one of the reasons that a UV index meter is so important

The easiest way to work with this sensor is to buy a module – this is a picture of the module that I bought

Parts Required

Schematic/Connection

Here are the connectors on the launchpad

Code

[codesyntax lang=”cpp”]

#include <Wire.h>

// VEML6070 I2C address is 0x38(56)
#define Addr 0x38

void setup()
{
  // Initialise I2C communication as MASTER
  Wire.begin();
  // Initialise serial communication, set baud rate = 9600
  Serial.begin(9600);
  
    // Start I2C Transmission
    Wire.beginTransmission(Addr);
    // Select command register
    // Integration time = 0.5T, shutdown mode disable 
    Wire.write(0x02);
    // Stop I2C Transmission
    Wire.endTransmission();
  delay(300);
}

void loop() 
{
  unsigned int data[2];
  
  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select data msb register
  Wire.write(0x73);
  // Stop I2C Transmission
    Wire.endTransmission();
    
  // Request 1 byte of data
  Wire.requestFrom(Addr, 1);
  
  // Read 1 byte of data
    if(Wire.available() == 1)
    {
    data[0] = Wire.read();
    }
    
  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select data register
  Wire.write(0x71);
    // Stop I2C Transmission
    Wire.endTransmission();
    
  // Request 1 byte of data
    Wire.requestFrom(Addr, 1);
    
    // Read 1 byte of data
    if(Wire.available() == 1)
    {
        data[1] = Wire.read();
    }
  
  // Convert the data
  float uvlight = data[0] * 256.0 + data[1];
  
  // Output data to serial monitor
    Serial.print("UV Light Of The Device");
    Serial.println(uvlight);
    delay(1000);     
}

[/codesyntax]

Output

Open the serial monitor – just as a note in my example I was indoors – hence the UV value was 0

UV light level: 0
UV light level: 0
UV light level: 0
UV light level: 0