Introduction: Turn a Clock Into an Automatic Fish Feeder

Reliable, easy to make, inexpensive; this really is a better fish feeder. This fish feeder provides an automatic, inexpensive, consistent, measurable way of feeding fish on a daily basis for an extended period of time. The fish feeder works best with a dry, granular fish food.

Step 1: Materials

For this project, you'll need:

  • An inexpensive, simple battery-powered wall clock with a plastic face
  • 1 sheet of overhead plastic material (transparent acetate)
  • tape
  • silicon glue

Step 2: Remove the Plastic Face Cover

Remove the clear plastic cover face from the clock. You may need to press the holding flanges in so that the plastic face can be removed intact. Cut off these flanges so the clock cover can rotate within the clock.

Step 3: Remove the Second and Minute Hands

Remove the plastic second and minute hands from the clock.

Bend the hour hand near the center so that it is perpendicular to the clock face. This hand should just clear the face of the clock as it passes through a 12 hour cycle.

Cut off all but ½ inch of the second hand and replace it.

Step 4: Drill a Hole in the Cover

Carefully drill a ½ inch hole in the plastic face so that the hole will fall about half way along the hour hand. Be careful, it is easy to split the face. A brad point bit may cut best. Measure the distance this hole is from the center of the face.

Step 5: Make a Funnel

Make a gently tapering cone with the plastic overhead film. The small end of this cone should just pass through the hole in the clock face. Tape the cone so that it keeps its shape. This will be the fish feed holder. The food will fall through the plastic cone making a pile of food below the cone. The size of this pile will depend on the size of the bottom cone opening and how far the cone bottom is above the clock face.

Step 6: Drill a Hole in the Body of the Clock

Look at the bottom of the clock to determine where the clock works are located, then drill a ¼ inch hole at the same distance from the center as the hole in the face and away from the clock works. This hole may need to be increased in size to allow more fish food to fall through.

Step 7: Testing the Automatic Feeder

Place the clock with the food above a sheet of paper. Then let the system run for 24 hours.

Weigh the amount of food to determine the amount of food that will drop into.

You can increase the food delivered in two ways:

  • making the pile under the cone larger, and/or
  • increasing the size of the hole in the clock face.

Carefully observe the face to see how much food is spread around before deciding which of these actions to take.

If you know the amount of food you are feeding, you can calculate fish weight gain and feed to fish conversion.

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