I just returned from vacation with my wife, but before I left I realized that our fish would be going unfed longer than I would like.  Rather than ask someone to feed the fish for us I whipped up a quick fish feeder that would feed them for two days.  I think I might work on modifying this and build a nicer more permanent fish feeder that I can use when we go away on our Cruise in January for 8 days.  The feeder was composed of 2 servos connected to the Arduino with 2 small cups attached to the servo horns.  The feeder started a timer that waited one day from when it was turned on to turn the 1st servo 180 degrees dumping the cup full of food.  After another day the second servo turned 180 degrees and dumped the other cup of food.  I taped the servos to the top of the fish tank and powered the Arduino using an AC-DC power cord. There are more pictures in my Flickr stream.  Ugly but it got the job done.

Fish feeder overhead view

Fish feeder overhead view

Code:

#include <Servo.h> 

Servo myservo1;  // create servo object to control a servo
Servo myservo2;  // create servo object to control a servo 

void setup()
{
  myservo1.attach(9,550,2150);  // attaches the servo on pin 9 to the servo object
  myservo1.write(0);              // tell servo to go to position 0 deg
  myservo2.attach(10,800,2200);  // attaches the servo on pin 10 to the servo object
  myservo2.write(0);              // tell servo to go to position 0 deg
} 

void loop()
{
  delay (86400000);
  myservo1.write(180);
  delay (5000);
  myservo1.write(0);
  delay (86400000);
  myservo2.write(180);
  delay (5000);
  myservo2.write(0);
}