/*
* The file reads the light intensity, lights up the LED according to the brightness of the room, and shows the level of light intensity from 0-9 on the 7-segment display
*/
#define LEVEL0 25
#define LEVEL1 50
#define LEVEL2 75
#define LEVEL3 100
#define LEVEL4 125
#define LEVEL5 150
#define LEVEL6 175
#define LEVEL7 200
#define LEVEL8 225
#define LEVEL9 255
// Define the LED digit patterns for 0 - 9 in a 2 dimensional array.
// The 2D array (an array of arrays or a matrix) has 10 arrays that each
// contain 7 values.
// Note that these patterns are for common cathode displays. For common
// anode displays, change the 1's to 0's and 0's to 1's
// 1 = LED on, 0 = LED off, in this order:
// Common Anode version
byte seven_segment_digits[10][7] = { { 0,0,0,0,0,0,1 }, // display '0'
{ 1,0,0,1,1,1,1 }, // display '1'
{ 0,0,1,0,0,1,0 }, // display '2'
{ 0,0,0,0,1,1,0 }, // display '3'
{ 1,0,0,1,1,0,0 }, // display '4'
{ 0,1,0,0,1,0,0 }, // display '5'
{ 0,1,0,0,0,0,0 }, // display '6'
{ 0,0,0,1,1,1,1 }, // display '7'
{ 0,0,0,0,0,0,0 }, // display '8'
{ 0,0,0,1,1,0,0 } // display '9'
};
/*
* Identify level of the light and display
* the number
*/
void displayLight(int lightlevel) {
if (lightlevel <= LEVEL0)
displayNumber(0);
else if (lightlevel <= LEVEL1)
displayNumber(1);
else if (lightlevel <= LEVEL2)
displayNumber(2);
else if (lightlevel <= LEVEL3)
displayNumber(3);
else if (lightlevel <= LEVEL4)
displayNumber(4);
else if (lightlevel <= LEVEL5)
displayNumber(5);
else if (lightlevel <= LEVEL6)
displayNumber(6);
else if (lightlevel <= LEVEL7)
displayNumber(7);
else if (lightlevel <= LEVEL8)
displayNumber(8);
else if (lightlevel <= LEVEL9)
displayNumber(9);
}
/*
* Displays the number on the 7-segment display
*/
void displayNumber(int num)
{
int pin = 3;
for (int segCount = 0; segCount < 7; ++segCount) {
digitalWrite(pin, seven_segment_digits[num][segCount]);
++pin;
}
delay(1000); // this is the same as delay() but saves power
}
/*
*In the setup function, we set our LED pins as OUTPUT.
*/
void setup() {
Serial.begin(9600); // initialize serial communication
pinMode(19, OUTPUT); // sets the LED on pin 19 to output
pinMode(3, OUTPUT); // set segment A as output
pinMode(4, OUTPUT); // set segment B as output
pinMode(5, OUTPUT); // set segment C as output
pinMode(6, OUTPUT); // set segment D as output
pinMode(7, OUTPUT); // set segment E as output
pinMode(8, OUTPUT); // set segment F as output
pinMode(9, OUTPUT); // set segment G as output
pinMode(10, OUTPUT); // set dot as output
for(int i = 3; i < 10; i++) { // start with segments off
digitalWrite(i, HIGH);
}
digitalWrite(10, HIGH); // start with the dot off
}
void loop() {
int lightLevel = analogRead(2); // Read the light level from analog pin 2
delay(1); // delay for 1 millisecond for smoothness
Serial.println(lightLevel); // Print the analog value to Serial
// adjust the value 0 to max resolution to span 0 to 255
lightLevel = map(lightLevel, 0, 4096, 0, 255);
lightLevel = constrain(lightLevel, 0, 255); // constrain values between 0-255
Serial.println(lightLevel); // Print the digital value to Serial
analogWrite(19, lightLevel); // Write the PWM value to the LED
displayLight(lightLevel); // Displays the number on 7-segment display according to the light level
delay(1000); // this is the same as delay() but saves power
}
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