A project log for Cardboard Hovercraft Robot

Answering the question: Why aren't there more robotic hovercrafts?

cruz-monrreal-iiCruz Monrreal II 07/08/2014 at 05:040 Comments

Wow. I didn't actually expect this to work nearly as well as it has. Apparently cardboard + paperclips + solder + servo = working rudders!

So here's the thing. For the longest time, I had wanted to make rudders for the hovercraft. The problem with this is that this would introduce a custom mechanical component to the design that would require replacement if it failed (trying to keep the design as simple and straightforward as possible; KISS). Unfortunately, I've reached the point where I'm short on time and I don't think I'll have the time to get the EDF thrust non-linearity issue (from way back) sorted out in time. I would much rather be able to set a speed for both EDFs, and simply interact with the rudder angle, getting rid of a variable from the control problem (two EDFs vs one servo).

So now that that was decided, it's time to figure out how to make one, without much time left. Because this part would be under constant actuation, I needed to make sure it would hold up, make sure it would be sturdy, but also needed it to be cheap and easy to duplicate. It's the trifecta problem: cheap, fast, good. Pick two.

This is where an old problem became a most WONDERFUL solution. Early in the project when I started using cardboard, I noted that its main issue was its perforation. There was no way for me to create an air chamber to use for hovering, without closing off the perforations with tape, due to the way I was constructing the hovercraft. The rudder design I was able to come up with, actually takes advantage of these perforations for structural support.

But what about the actuation? This was some cleverness on my part that I learned about a couple of months back when I was using cardboard for a different project. It turns out, that it's really easy to make cardboard bend to whatever angle you want it to with a metal ruler and a mallet. This same "technique" I used to make the cardboard flaps, which also happen to be part of the support structure itself. Awesome.

Ok, last step. I now have structurally sound rudders, I have flaps that I can now move freely, now I just need to figure out how to move them together. In comes paperclips and the soldering iron.

A few years ago (junior year of high school if I recall), for some reason, I set out to solder together paperclips. I don't know why, but I just did. I remember it working well enough that I stashed it away in the back of my head as another "technique", to be used again when needed. Fast forward to now, and my soldering skills have only gotten better.

With the paper clips in hand, I bent four pieces 90 degrees, pushed them into the flaps, about 1/2" from the end, and pushed them in as parallel to the end as I could. They punctured the top of the flaps, I soldered them together, and made another small piece that freely rotated in the servo horn, until it was soldered as well. And wouldn't you know it, it works! I might add some hot glue or tape to the paper clips poking through the top of the hovercraft just to make sure they don't sag down and drag on the battery.

Not bad if I do say so myself!