Rapid Prototyping with Cardboard

Before coming to ITP, I had never used Adobe Illustrator (Ai) or a laser cutter. I’m very happy that has changed.

I was previously working on an automated dog feeder project, but had been struggling with material handling. My original design involved a single ramp inside a box, angled toward an opening in the bottom that was blocked by a piece moved by a servo. Unfortunately, the dog food would continuously jam in the opening with this method.

I redesigned the whole thing for version 2.

The new design funnels the dog food to a single point and dumps it into a “wheel” with cross sections that catch the food. The cross section wheel is moved by a servo, which dumps the controlled amount into a final chute and comes out into the dog’s bowl from there:

I grabbed a spare cardboard box and cut it into long pieces with a box cutter:

Building out a template file in Ai:

It’s alive! I used 30% speed and 90% power to start with, had to make 2 passes:

My first cut on a laser cutter:

Putting the pieces together:

Hard to tell from the photo, but they’re a little lose after the first try:

I reduced the gap down to .15″ and played with a variety of sizes for the circle and height of the X:

I settled on a 7″ circle with 3″ high sides:

Setting up my breadboard + arduino + servo:

September 26, 2017


Nice work. Glad you iterated on a design in cardboard. A couple of things, if cardboard isn’t your final material, you will have to resize the slit in the pieces of the “X” all over again. How do you plan to attach the X to the circle? Glue?

Friction will be the enemy in this design. I would test with actual dog food, see if the servo can handle the load, see if nothing gets jammed up, see if the material holds up, etc.

Thanks Ben. I plan to use acrylic for the final project. For the cardboard, I attached the X to the circle using hot glue/for the acrylic I plan to use the chemical bonding glue.

I’ve got a high torque, metal gear servo that I am planning to use to drive the “dumping” motion. Good point about testing for jams, etc.

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