Thursday, January 1, 2015

Arduino-Driven 3D Printed Fish Feeder -- Take Two

January 1, 2015 Away for New Year's while our latest 3D creation is hopefully and dutifully feeding the fish in our aquaponics system, we have been pleasantly surprised by the feedback we've gotten. even covered it and I suspect it was their article that spurred many requests for the .STL files for the feeder.

left is our original design fully printed and currently working as part of our automated aquaponics system. right is our V.2 which is visibly heavier and larger to eliminate the fragility of version 1. The auger is also radically redesigned.

However, this was the very first thing we ever printed out for an actual design project. It is also the first object we've printed out that needed to be fit together. There was so much filing, sanding, and gluing that I believe many would feel defeated after waiting for each part to be printed out only to end up with all that work still to do. Not only that, but many of the tabs and slots we designed into it were way too small and many broke off. The auger too, required much delicate carving to get it to move the fish food out without binding up and stopping the servo.

It is a cool project because within a week, despite all the extra work, it finally did actually work, but to distribute it, even for free, wouldn't be so cool. So we are working on version two (v.2). V.2 is already laid out in SketchUp and will be printed out, assembled, and tested, and if it goes smoothly we will post all the files. In addition to that, all of those who contacted us will get a set of .STL files sent to them.


Everything will be thicker -- at least 2mm thick or more. Instead of tabs, we will use T-slots and small 2mm servo screws. The auger will have fewer turns along its axis, and the blade will taper to a point instead of remaining 2mm across the width. The auger will also be designed to be fitted to the servo, then passed through the electronics compartment into the hopper. I had a lot of trouble attaching the auger to the servo and keeping it attached. The number one biggest fear for when we return to the office after New Year is to find the auger detached from the servo meaning it was spinning everyday but never delivering any food. 

The auger for version 1 included many turns around its axis and the blades had flat edges. There was no tapering at all leading to the auger grinding the fish food and either jamming the servo or twisting the auger off its fittings with the servo. The new design has far fewer turns and a tapered blade. It is also designed with a larger gap between its blade edges and the shaft.

The fish feeder is a small project -- one that can be designed and working within a week, but it is a project we hope will serve as the first of many as part of our CityFarmBKK (City Farm Bangkok) project to automate urban agriculture to make it accessible for busy people, which in turn is part of a larger project to augment agricultural practices in the countryside with technological solutions.

Reliable automation means you can do more, whether that means more agriculture or more of something else entirely.

Anyway, thanks for everyone's compliments, we are really flattered. And thanks for your patience while we get this new and improved version suitable for others to try to replicate out after the New Year's holiday!

Can't Wait for Version 2?

If you are really itching to make this, the one thing that won't be changing is the servo and Arduino driving it. So maybe check back on how we set the servo and Arduino up, and start testing yours.

Here's a checklist of what you'll need:
  • An Arduino with a USB cable
  • A USB power adapter (1 amp) 
  • A 9g micro servo with plastic gears
Once you convert your servo to continuous motion and upload the code to your Arduino, practice setting different feeding times and feeding rates (determined by how long you set the servo to spin each feeding time). Leave it plugged in overnight so you can see it perform each day as you set it.

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