Arduino Intermediate Kit Tutorial 14: Pandora’s Box

Do you dare to open Pandora’s box?
The box we will make today will be closed during the daytime, but when night comes it will gradually open and the light inside will gradually glow bright.
An analog ambient light sensor is used to detect the intensity of light outside the box. When the value reaches the limit for the night, the servo will move, opening the box and an inner-led will glow brighter.

COMPONENTS

1×  Analog Ambient Light Sensor V2
1×  TowerPro SG50 Servo
1×  Digital Piranha LED-R
1× DFRduion UNO R3 (similar as Arduino UNO)
1× IO Expansion Shield for Arduino V7.1

HARDWARE CONNECTIONS
Connect the TowerPro SG50 Servo to digital pin 9 on the DFRduino
Connect the Analog Ambient Light Sensor V2 to analog pin 0 on the DFRduinio
Connect the Digital Piranha LED-R to digital pin 3 on the DFRduino

You can refer to the diagram below for reference:

Be sure that your power, ground and signal corrections are correct or you risk damaging your components.

When you have connected the components and checked your connections, plug the Arduino in to your PC with the USB cable so you can upload a program to the DFRduino.

CODE INPUT
Sample Code 11-1:

    #include <Servo.h>    
Servo myservo;
int LED = 3;   //Set the LED light to be digital pin 3
int val = 0;   // val stores analog ambient light sensor’s value
int pos = 0;
int light =0;


void setup(){
     pinMode(LED,OUTPUT);         // LED is set to be in the output mode
Serial.begin(9600);          //Baud rate of the serial port is set to be 9600
myservo.attach(9);           // attach the servo to digital pin 9
myservo.write(0);            // initial angle is 0
}
void loop(){

val = analogRead(0);         //read the analog ambient light sensor’s value
Serial.println(val);         //Check sensor value in serial port
if(val<40){                   // when val is less than the pre-set value, increase the angle
          pos = pos +2;
          if(pos >= 90){        //The angle should not be more than 90
              pos = 90;              
          }
          myservo.write(pos);      //write angle of the servo
          delay(100);
          light = map(pos,0,90,0,255);  //As the angle expands, the LED becomes brighter
          analogWrite(LED,light);   //write the brightness value 
     }else{                  
          pos = pos -2;    //decrease 2°
          if(pos <= 0){
pos = 0;       //until 0°
          }
          myservo.write(pos);      //write angle of the servo
          delay(100);     
          light = map(pos,0,90,0,255);//As the angle shrinks, the LED light becomes darker
          analogWrite(LED,light);  //write the brightness value 
     }
}

Use this sample code to implement the behavior we want.
You can copy and paste it in to the Arduino IDE, but if you want to develop you skills we recommend typing it out.

When you have finished, click “Verify” to check the code for syntax errors. If the code verifies successfully, you can upload it to your Arduino.

Attach the servo on to the hinge of the box so that the arm is able to open it. The ambient light sensor needs to be placed outside the box to detect the ambient lighting. The LED is placed inside the box.

Place the box somewhere dark and check if it opens automatically.

If you have questions about the functions in the sample code, please refer to the previous sessions for details.

If you have any questions, please feel free to comment.
There is also another best selling arduino starter kit for you to choose.
Related category: arduino kits > education kits
Last Arduino Tutorial:  Arduino Intermediate Kit Tutorial 13: Open Sesame!
Next Arduino Tutorial: Arduino Intermediate Kit Tutorial 15: Remote Controlled LED