Automatic Fish Feeder

Time to add to my laziness and add some more automation.  I no longer have to feed the fish a few times a day...however I still like to just stand there an watch them.  What is it about them that's so mesmerizing???




This is a small automatic feeder that I made which holds about 4 tenths of a liter of fish food and has been running for a few years.  I built this larger one for the new greenhouse which holds 2.8 liters.

The feed is controlled by a regular 3/4 inch wood auger bit which fits nicely into a housing which is a piece of 3/4 inch black pipe.  This is driven by a 12 volt DC gear motor I got from a surplus store.  This is a great motor since it has a slot instead of a drive axle so it’s easy to make the auger bit fit into it.

First I cut down the auger bit to the right length and grind down the shaft so that it fits into the slot of the gear motor.  I then cut out the center of the black pipe.  This is where the feed hopper will connect to the auger housing.  A small piece of flat bar is used as a mounting bracket which will allow it to be mounted to the tank and attach the motor to the shaft.

After carefully setting up the pieces, I tack weld the auger housing to the mounting bracket, then remove the motor and finish welding the pieces together.

The feed hopper is made from an old computer cover.  I made up a cutting template for the various pieces and sprayed adhesive to the cover to hold the templates while cutting.

I built in some tabs to the hopper walls so I could weld the pieces together.  This is the point in time where I which I owned a metal break, but had to improvise with my vice and hammer.  Luckily, the bends were not too complex.

After all the pieces were bent into shape, I ground off the paint so the seams could be welded together.  I also drilled holes through the walls where the tabs would connect.  This is so I could weld a tack through the hole to connect the thin sheets together.  It’s similar to riveting the pieces together.  

When the hopper is welded together, I grind the welding tacks down so they are flush with the sheet metal.  The last bit of welding is to attach the auger assembly to the hopper.

I am fortunate to have access to a nice sand-blasting cabinet.  This quickly and easily removes any loose paint and rust and makes a really clean surface to paint.  After a couple of coats of paint, it looks almost as nice as work done by a pro ….almost.

I made up a level switch that turns on an LED to let me know when the feed is getting low in the hopper.  I took a bamboo skewer and hot-glued it to a micro switch.  The newly extended lever reaches into the hopper and has a float that hangs from it.  When the level goes to low, the float will pull down on the lever and light the LED.  I also added a momentary switch into the box which allows me to turn on the auger in case I feel like giving the fish a bonus snack.

I mounted the level switch box to the hopper and connected the motor wires through the box.  Then the new feeder was bolted to the side of the stock tank.  For now, I connected the feeder to one of our IX-180 index timers.  It is programmed to run the auger bit for 20 seconds, four times per day.  The extra input of the timer is used to monitor the water temperature in the tank.  Eventually, the feeder, vents and other controls will be connected to a master automation system.

Here’s the float that sits on top of the food, when it gets low enough, it just pulls down on the lever and turns on the LED and this is the feeder in operation.     Thanks for watching!  Make sure you subscribe to this channel for more great videos!