Using what we learned last class, I decided to use three red lights to alert the workers at the library when something needs to be checked out.  The idea is that when there are more items stacked in the box, or if there is just a heavy item, more of the red lights will light up letting the workers know.

IMG_4819

```int brightness;
int green[] = {2,4,6};
int red[] = {13, 11, 9};

void setup(){
//Green
pinMode(2,OUTPUT);
pinMode(4,OUTPUT);
pinMode(6,OUTPUT);

//Red
pinMode(13,OUTPUT);
pinMode(11,OUTPUT);
pinMode(9,OUTPUT);

Serial.begin(9600);
}//setup

void loop(){

map(brightness, 0,255, 0, 255);

//When the box is empty, green lights light up
if(brightness>255){
//Red:OFF
for (int i=0; i<3; i++){
digitalWrite(red[i],LOW);
}
//Green
for (int i=0; i<3; i++){
digitalWrite(green[i], HIGH);
}
}

//When there are periodicals, the green lights turn off and the red lights turn on
if(brightness >= 190 && brightness < 255){
//Red
for (int i=0; i<1; i++){
digitalWrite(red[i], brightness);
}
//Green: OFF
for (int i=0; i<3; i++){
digitalWrite(green[i],LOW); }
}

if(brightness >= 100 && brightness < 190){
//Red
for (int i=0; i<2; i++){
digitalWrite(red[i],brightness);
}
//Green: OFF
for (int i=0; i<3; i++){
digitalWrite(green[i],LOW);
}
}

if(brightness >= 0 && brightness < 100){
//Red
for (int i=0; i<3; i++){
digitalWrite(red[i],brightness);
}
//Green: OFF
for (int i=0; i<3; i++){
digitalWrite(green[i],LOW);
}
}
}//loop```