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Measure And Display The Ambient Light With Pmod & Arduino

About the project

This project uses Pmod ALS and Arduino Uno to measure and display the ambient light. In this app, the value of the amount of light is displayed on the serial monitor.

Project info

Difficulty: Easy

Platforms: Arduino, Digilent

Estimated time: 1 hour

License: GNU General Public License, version 3 or later (GPL3+)

Items used in this project

Hardware components

Pmod ALS https://ro.mouser.com/ProductDetail/Digilent/410-286?qs=s%2FdyVPQMB4xDa7o7sikQHw%3D%3D

x 1

Software apps and online services

Arduino

Story

This is a demo project for the Digilent Pmod ALS. The ambient light intensity is measured, converted to an 8-bit number, and displayed on the Serial monitor. To control the Pmod, an Arduino UNO is used, which also sends the data to the computer. To communicate with the peripheral device, SPI communication protocol is used, in mode 0, with a serial clock frequency between 1MHz and 4MHz. Data is sent in 2 bytes, with 3 leading and 4 trailing zeros, which should be eliminated at processing and is displayed one measurement in a line. The sensor saturates at an output value of 125.

Schematics, diagrams and documents

Pmod ALS and Arduino Uno Fritzing Image

Code

Pmod ALS and Arduino Uno Code

/************************************************************************

  Test of Pmod ALS

*************************************************************************

  Description: Pmod_ALS
  The value of the amount of light is displayed on the serial monitor.
  (The sensor is saturated to a value of about 125)


  Material
  1. Arduino Uno
  2. Pmod ALS module

  Wiring
  Module<----------> Arduino
  VCC     to        3V3
  GND     to        GND
  SCK     to        13 (SCK)
  SDO     to        12 (MISO)
  CS      to        10 (CS)

************************************************************************/

#define CS 10 // Assignment of the CS pin

#include <SPI.h> // call library

void setup()
{
  Serial.begin(9600); // initialization of serial communication
  SPI.begin(); // initialization of SPI port
  SPI.setDataMode(SPI_MODE0); // configuration of SPI communication in mode 0
  SPI.setClockDivider(SPI_CLOCK_DIV16); // configuration of clock at 1MHz
  pinMode(CS, OUTPUT); //configure pin connected to chip select as output
}

void loop()
{
  byte intensity = 0;
  digitalWrite(CS, LOW); // activation of CS line
  intensity = SPI.transfer(0) << 3; // Aquisition of first 5 bits of data without leading zeros
  intensity |= (SPI.transfer(0) >> 4); //Aquisition of last 3 bits of data and appending
  digitalWrite(CS, HIGH);

  //display result
  Serial.print("Light intensity = ");
  Serial.println(intensity);
  delay(1000);
}

Credits

Digilent Inc

Digilent Inc., a National Instruments company, is a leader in the design, manufacture and worldwide distribution of FPGA development boards and Test and Measurement devices for both industry and education. Since our founding in 2000, Digilent has partnered with different leading semiconductor companies including Xilinx, Microchip, Analog Devices, ISSI and Texas Instruments to bring products with the latest embedded & electronics technology. Our expert team of engineers, combined with our manufacturing services and worldwide distribution has made us an ideal partner for several leading technology providers. We want to enable our partners to be successful through well designed, high quality and well manufactured hardware.

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Measure And Display The Ambient Light With Pmod & Arduino

About the project

Project info