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Light Spectrogram
/**
* Qwiic Mux Spectral Demo
* Author: Shawn Hymel (SparkFun Electronics)
* Date: July 18, 2018
*
* Reads from 2 light spectral sensors and shows amount of light
* detected in each channel.
*
* Connect Qwiic Mux and Qwiic OLED to Arduino. Connect Visible
* (AS7262) and NIR (AS7263) Spectral Sensor Qwiic Breakout
* Boards to the Mux.
*
* This sketch was written by SparkFun Electronics, with lots of
* help from the Arduino community. This code is completely free
* for any use.
*/
#include <Wire.h>
#include <SFE_MicroOLED.h> // https://github.com/sparkfun/SparkFun_Micro_OLED_Arduino_Library
#include <AS726X.h> // https://github.com/sparkfun/SparkFun_AS726X_Arduino_Library
// Parameters
const int MUX_ADDR = 0x70;
const int VIS_CHANNEL = 0;
const int NIR_CHANNEL = 1;
// Pins
const int PIN_RESET = 9;
const int DC_JUMPER = 1;
// Constants
const uint16_t MAX_LIGHT = 50000;
const uint16_t LIGHT_PER_PIXEL = (MAX_LIGHT / LCDHEIGHT) + 1;
// Globals
MicroOLED oled(PIN_RESET, DC_JUMPER);
AS726X spec;
void setup() {
// Initialize communcation ports
Serial.begin(115200);
Wire.begin();
// Initialize OLED
delay(100);
oled.begin();
oled.clear(ALL);
oled.display();
// Initialize visible spectral sensor
enableMuxPort(VIS_CHANNEL);
spec.begin();
disableMuxPort(VIS_CHANNEL);
// Initialize NIR spectral sensor
enableMuxPort(NIR_CHANNEL);
spec.begin();
disableMuxPort(NIR_CHANNEL);
}
void loop() {
uint16_t light[12];
uint16_t ys[12];
// Take measurements from visible spectral sensor
enableMuxPort(VIS_CHANNEL);
spec.takeMeasurements();
light[0] = spec.getViolet();
light[1] = spec.getBlue();
light[2] = spec.getGreen();
light[3] = spec.getYellow();
light[4] = spec.getOrange();
light[5] = spec.getRed();
disableMuxPort(VIS_CHANNEL);
// Take measurements from NIR spectral sensor
enableMuxPort(NIR_CHANNEL);
spec.takeMeasurements();
light[6] = spec.getR();
light[7] = spec.getS();
light[8] = spec.getT();
light[9] = spec.getU();
light[10] = spec.getV();
light[11] = spec.getW();
disableMuxPort(NIR_CHANNEL);
// Print out all channels
for ( int i = 0; i < 12; i++ ) {
Serial.print(light[i]);
Serial.print(" ");
}
Serial.println();
// Convert spectral readings to y-axis position
for (int i = 0; i < 12; i++ ) {
if ( light[i] > MAX_LIGHT ) {
light[i] = MAX_LIGHT;
}
ys[i] = (LCDHEIGHT - 1) - (light[i] / LIGHT_PER_PIXEL);
}
// Draw spectrum
oled.clear(PAGE);
drawBar(6, ys[0]); // 450 nm
drawBar(12, ys[1]); // 500 nm
drawBar(18, ys[2]); // 550 nm
drawBar(21, ys[3]); // 570 nm
drawBar(25, ys[4]); // 600 nm
drawBar(31, ys[5]); // 650 nm
drawBar(26, ys[6]); // 610 nm
drawBar(35, ys[7]); // 680 nm
drawBar(41, ys[8]); // 730 nm
drawBar(45, ys[9]); // 760 nm
drawBar(51, ys[10]); // 810 nm
drawBar(57, ys[11]); // 860 nm
// Draw to OLED
oled.display();
}
// Draw a pixel and the two pixels next to it
void drawBar(uint8_t x, uint8_t y) {
// Check for out of bounds
if ( (x >= LCDWIDTH) || (y >= LCDHEIGHT) ) {
return;
}
// Draw bar
if ( x > 0 ) {
oled.pixel(x - 1, y);
}
oled.pixel(x, y);
if ( x < LCDWIDTH - 1 ) {
oled.pixel(x + 1, y);
}
}
//Enables a specific port number
boolean enableMuxPort(byte portNumber)
{
if(portNumber > 7) portNumber = 7;
//Read the current mux settings
Wire.requestFrom(MUX_ADDR, 1);
if(!Wire.available()) return(false); //Error
byte settings = Wire.read();
//Set the wanted bit to enable the port
settings |= (1 << portNumber);
Wire.beginTransmission(MUX_ADDR);
Wire.write(settings);
Wire.endTransmission();
return(true);
}
//Disables a specific port number
boolean disableMuxPort(byte portNumber)
{
if(portNumber > 7) portNumber = 7;
//Read the current mux settings
Wire.requestFrom(MUX_ADDR, 1);
if(!Wire.available()) return(false); //Error
byte settings = Wire.read();
//Clear the wanted bit to disable the port
settings &= ~(1 << portNumber);
Wire.beginTransmission(MUX_ADDR);
Wire.write(settings);
Wire.endTransmission();
return(true);
}
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