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# Create a Night Light
This is an example of using an input (sensor) component to change an output of an output component.
## Supplies
| | |
| ------------------------------------------------------------------- | ---------------------------------------------------------- |
| 
| Circuit Board |
| 
| Breadboard |
| 
| Jumper Cables |
| 
| Photoresistor
(light sensor)
|
| 
| Standalone LED Light
(any color with 2 leads)
|
| 
| 100 Ohm Resistor |
| 
| 220 Ohm Resistor |
## Diagram
The photoresistor data (yellow) is connected to pin A0 (analog) and the LED data (orange) is connected to pin 2 (digital).
## Code
This code gets the amount of light coming in via the sensor and if it's dark enough, the LED will light up.
```cpp
// Sensor pin is connected to pin A0 (analog) on the Arduino circuit board
int sensorPin = 0;
// LED pin is connected to pin 2 (digital)
int LEDpin = 2;
// Define variables
int lightValue;
void setup() {
// Establish the component connection and its type (output/input)
pinMode(sensorPin, INPUT);
pinMode(LEDpin, OUTPUT);
// Start Serial connection
Serial.begin(9600);
}
void loop() {
// Reads and stores the data coming in from the sensor
lightValue = analogRead(sensorPin);
// Lights up if dark enough
if (lightValue <= 5) {
digitalWrite(LEDpin, HIGH);
}
else {
digitalWrite(LEDpin, LOW);
}
delay(100);
// Sends information to the Serial Monitor
Serial.print("Light Value: ");
Serial.print(lightValue);
delay(100);
}
```
---
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