LED Globe

A small 5 cm hollow sphere which has a base and a hole for a 5mm LED.
I used mine with an RGB led and Arduino, and made it into a Pomodoro timer. It starts green, fades to red over 25 minutes, then for 4 minutes glows blue, signalling a stretch break.
Detailed instructions for creating the Pomodoro timer are below.



Instructions
Print out the Sphere in a neutral or white colour. Insert 5mm LED of your choice into the bottom and power it however you like!
If you want to build the Pomodoro timer which I did, follow this instructable for building the RGB LED circuit for the Arduino, which is what I used: http://www.instructables.com/id/Fading-RGB-LED-Arduino/. It give clear steps and materials required.
The code I wrote for the Pomodoro specific logic is here:
#define RED 9
#define GREEN 10
#define BLUE 11

void setup() {

pinMode(GREEN, OUTPUT);
pinMode(BLUE, OUTPUT);
pinMode(RED, OUTPUT);
digitalWrite(GREEN, HIGH);
digitalWrite(BLUE, LOW);
digitalWrite(RED, LOW);
}

int redVal;
int blueVal;
int greenVal;
int val;

void loop() {

// 25 minute green to red

int redVal = 0;
int blueVal = 0;
int greenVal = 255;
for( int i = 0 ; i < 255 ; i += 1 ){
greenVal -= 1;
redVal += 1;
analogWrite( GREEN, greenVal );
analogWrite( RED, redVal );

delay( 5882 );
}

// blink red

for ( int i = 0; i < 60; i++ ) {
redVal = ( redVal == 0 ) ? 255 : 0;
analogWrite( RED, redVal );

delay ( 500 );
}

// 4 minute solid blue

analogWrite( RED, 0 );
analogWrite( BLUE, 255 );
delay( 240000 );

// blink blue

for ( int i = 0; i < 60; i++ ) {
val = ( val == 0 ) ? 255 : 0;
analogWrite( BLUE, val );

delay ( 500 );
}

analogWrite ( BLUE, 0 );

}