Hovercraft

The Hovercraft

February 26:

As this is my first post, it will mostly be updating on the project I have been working on for the past month or so. My friend and I have been working with the Georgia Tech i-3 program for a few months now, and we have begun work on one of our major projects: the hovercraft. We were asked to re-vamp an old project that had never been finished. The chassis for the hovercraft was there, as well as the motors, but the wiring and other technical work, such as the batteries and boards, needed to be pulled out and redone. This was the first thing we did, which resulted in this:

The chassis is made out of a foam board, much like the kick-boards you would find at a local pool. The skirt is made out of a heavy plastic, with a hole cut in the bottom underneath the lifting propellor. This allows for the air to fill the skirt, as well as escape underneath it to prevent it blowing back through the lifting propellor, decreasing efficiency. As of now, only the hardware has been re-configured.

As of today, February 26th, we have configured the hardware as well as the coding. To power this, we are using an Arduino Uno and two E-flite Park 400 motors, pictured below.

To control these motors, we have connected ESCs (Electronic Speed Controllers) to the Arduino. The ESCs are necessary for controlling the speed of the motor. To achieve communication, the Arduino treats the ESCs as a servo, and sends a specific value to them that they run. An ESC is pictured below, connected to the Li-Po battery.

For the previous few weeks, my friend and I have been working on the coding, which we started learning by ourselves. For the first week, we barely got the motor to move an inch; we had a long way to go. Eventually, we determined the way the ESC and the Arduino communicate, after much trial and error, and on our first successful start-up burnt out the rear motor. Our success was bittersweet, and demonstrated how little we understood the mechanism we were working with at the time. So after removing the rear engine, shown below, and stripping out a few screwdrivers, we put our efforts into actually understanding the various components rather than just trying to "jimmy rig" the contraption.

After a week of research and learning from our mistake, we felt much more confident and returned to the construction side of the project, where we attached a new, more powerful motor to the back and a new ESC to control it, as the old one was, well, too old. Pictured below is the newly installed rear motor.

Luckily for us, we only shorted out one motor in our trial and error, and the one that provided lift was in good enough condition that we didn't need to replace it. Now all we needed was the code. After another week of coding on the Arduino software, we were ready to try it out. It went very well, as shown in the video below (I suggest skipping to about 0:34):

https://www.youtube.com/watch?v=sHO7jplkNTc

As you can see, the lift propellor was having some issues getting going, but that was due to the little charge left in the battery, not due to an error in coding. The hovercraft was under it's own power, and was simply set to go forward. Our next step will be to control it from the computer using an XBee shield.


February 28th:

Today we hooked up the Arduino to an XBee shield, allowing us to control the hovercraft through the computer much like one controls a remote control vehicle. For any of you who want to do the same, make sure you download the correct programs to setup the XBee, otherwise you won't be getting anywhere. The Arduino-XBee hardware is shown below.

April 4th:

As of today, the project has been completed. We got the XBee talking with the motors smoothly, and the servo on the back directing the hovercraft successfully. After a lot of trial and error, we got it running. We also learned a lot that we can apply to our next project, the I.R.I.S. Drone. We learned that the XBee is a limited serial port communicator, and so we're going to use a standard RC rig for the drone. We also learned how to use Arduino, a skill that we will need to use for I.R.I.S. project.