#define ADC_IN A5
#define ADC_REF 3.3   


char led_red = 23;
char led_yellow = 19;
char led_green = 18;

char pb_blue =25; 
char pb_green =27; 

void setup() {
  // put your step code here,to run once:
 pinMode(led_red,OUTPUT);
 pinMode(led_yellow, OUTPUT);
 pinMode(led_green, OUTPUT);
 pinMode(pb_blue, INPUT);
 pinMode(pb_green, INPUT);
 Serial.begin(115200);
}

void loop() {
  // put you main code here, to run sepeatedly:
int val_ADC; //N in the slide

//How to read the output of ADC?
val_ADC = analogRead(ADC_IN); //I use A5 (pin 33)

//Print output of ADC to Serial Monitor
Serial.print("ADC val = "); Serial.println(val_ADC,DEC);

//Voltage:  0-->3.3V; voltage is a real number
float voltage; //V in the slide
voltage = (val_ADC/4095.0) * ADC_REF;
//Print output the value of voltage
Serial.print("Voltage = "); Serial.println(voltage,DEC);

if (val_ADC <= 1000)
{
digitalWrite(led_green,HIGH);
digitalWrite(led_red, LOW);
 }
else if ( (val_ADC > 1000) && (val_ADC < 3500) ) 
{
digitalWrite(led_green,LOW);
digitalWrite(led_red,HIGH);
 }
 else 
 {
  digitalWrite(led_green, HIGH);
  digitalWrite(led_red, HIGH);
 }
 
}