/*
LED Bar Graph with Photoresistor Sensor
by Anderson Costa with ❤ for the Wokwi community
Visit https://wokwi.com to learn about the Wokwi Simulator
*/
// These constants should match the photoresistor's "gamma" and "rl10" attributes
const int sensorPin = A0; // Set pin of the Photoresistor sensor
const float GAMMA = 0.7;
const float RL10 = 50;
const int ledCount = 10; // Set number of LEDs in the bar graph
// Array of pins for LEDs in the bar graph
int ledPins[] = {
2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};
void setup() {
// Loop over the LEDs pins and set all to output
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
pinMode(ledPins[thisLed], OUTPUT);
}
}
void loop() {
// Read the Photoresistor sensor value
int sensorReading = analogRead(sensorPin);
// Convert the analog value into lux value
float voltage = sensorReading / 1024. * 5;
float resistance = 2000 * voltage / (1 - voltage / 5);
float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
// Map the result to a range from lux to the number of LEDs
int ledLevel = map(lux, 0, 1023, 0, ledCount);
// Loop over the LEDs pins and set element
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
// If the array element's index is less than ledLevel
if (thisLed < ledLevel) {
// Turn the pin for this element on
digitalWrite(ledPins[thisLed], HIGH);
} else {
// Turn off all pins higher than the ledLevel
digitalWrite(ledPins[thisLed], LOW);
}
}
}