Arduino Due and Si1145 sensor example

In this exampl;e we look at the Si1145 sensor, we connect it to an Arduino Due and use the Arduino IDE for development

First the sensor in a little more detail

The Si1145/46/47 is a low-power, reflectance-based, infrared proximity, ultraviolet (UV) index, and ambient light sensor with I2C digital interface and programmable event interrupt output. This touchless sensor IC includes an analog-to-digital converter, integrated high-sensitivity visible and infrared photodiodes, digital signal processor, and one, two, or three integrated infrared LED drivers with fifteen selectable drive levels. The Si1145/46/47 offers excellent performance under a wide dynamic range and a variety of light sources including direct sunlight. The Si1145/46/47 can also work under dark glass covers.

The photodiode response and associated digital conversion circuitry provide excellent immunity to artificial light flicker noise and natural light flutter noise. With two or more LEDs, the Si1146/47 is capable of supporting multiple-axis proximity motion detection. The Si1145/46/47 devices are provided in a 10-lead 2×2 mm QFN package and are capable of operation from 1.71 to 3.6 V over the –40 to +85 °C temperature range.

Parts List

Layout

Simple to connect being an I2C device – I used 3v3 on my sesnor

arduino due and si1145

Code

This example requires the Adafruit Si1145 library, you can add this via the library manager or download from https://github.com/adafruit/Adafruit_SI1145_Library

[codesyntax lang=”cpp”]

#include <Wire.h>
#include "Adafruit_SI1145.h"

Adafruit_SI1145 uv = Adafruit_SI1145();

void setup() {
  Serial.begin(9600);
  
  Serial.println("Adafruit SI1145 test");
  
  if (! uv.begin()) {
    Serial.println("Didn't find Si1145");
    while (1);
  }

  Serial.println("OK!");
}

void loop() {
  Serial.println("===================");
  Serial.print("Vis: "); Serial.println(uv.readVisible());
  Serial.print("IR: "); Serial.println(uv.readIR());
  
  // Uncomment if you have an IR LED attached to LED pin!
  //Serial.print("Prox: "); Serial.println(uv.readProx());

  float UVindex = uv.readUV();
  // the index is multiplied by 100 so to get the
  // integer index, divide by 100!
  UVindex /= 100.0;  
  Serial.print("UV: ");  Serial.println(UVindex);

  delay(1000);
}

[/codesyntax]

Output

Open the serial monitor window – these readings were taken indoors

Adafruit SI1145 test
OK!
===================
Vis: 256
IR: 281
UV: 0.02
===================
Vis: 263
IR: 280
UV: 0.03
===================
Vis: 261
IR: 279
UV: 0.02
===================

Link

https://www.silabs.com/documents/public/data-sheets/Si1145-46-47.pdf