• Anna Oh

Week3)The City Lights

For the third assignment, I was thinking about the idea of lighting. Since I have lived in Manhattan, watching the city night view is one of my joy while walking streets.

Inspired by this city night view, I came up with an idea which is the lighting has the shape of the building.And I thought the lighting controlled by lights using photosensor like the buildings were light up at nights.

This is a rough idea sketch for the lighting.

Actually, I was struggling and did lots of fails to figure it out to study digital input/output & analog input/output, eventually I can able to make the prototype.

For the beginning, I set up the photocell with the resistor and did a trial test to figure it out it is working for Arduino example 'analog input'.

After I confirmed the photocell setting, I set up the LED and got a test for Arduino example ' fade' and find out LED works well. And then I adjusted LED light length to the prototype of the building, started cording. It was almost 550 that photocell's value for natural light. So I make the LED light up when it's dark using map function - map(sensorValue, 0, 550, 255,0);

And I started to set up other LEDs in the same way.

This is final output of the prototype. You can see the lighting up when it's dark.


int sensorPin = A0;

int sensorValue = 0;


int led1 = 9;

int led2 = 10;

int led3 = 11;

int led4 = 6;

int led5 = 5;

int brigtness = 0;

void setup() {


pinMode(led1, OUTPUT);


void loop() {

sensorValue = analogRead(sensorPin);


int brightness = map(sensorValue, 0, 550, 255,0);



if (brightness < 10) {






} else{

analogWrite(led1, brightness);

analogWrite(led2, brightness);

analogWrite(led3, brightness);

analogWrite(led4, brightness);

analogWrite(led5, brightness);



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