Final Project


This blimp is made of helium filled balloons. Originally I intended to make my own balloon, which turned out to be more difficult than I had envisioned. So instead I used hot dog and cat balloons, which I thought was appropriate since two of my previous weekly projects feature either a hot dog or a cat. The blimp has three motors with 3D printed propellers. The motors are controlled remotely using IR communication between an IR LED on a joystick controller and an IR receiver on the PCB with the motors.

The motors with the propellers are attached to the underside of the blimp.

And it flies!

Admittedly, the blimp is difficult to control and is easily pushed by ambient air currents. It turns out propeller design and aerodynamics of the balloon are extremely non-trivial... So, here's a video of it crashing (not catastrophically... whew!) during a test flight.

Here's a close-up shot:

Testing the motors with the joystick controller

At first I couldn't get the motors to run on my first motor PCB. Then, from the datasheet for the H-bridges I was using, I figured out that I needed at least 7 volts for the H-bridge to drive the motor. However, weight was a huge issue for the blimp, so I couldn't just use a heavy 9V battery. So I had to re-designed the board and put two li-po batteries in series. Then I added a 5V regulator to bring the voltage down for the microcontroller. This worked, and the motors were then able to run.

Using an Arduino libary called called IR Remote, I programmed the joystick controller board to have the IR LED send out IR signals corresponding to different joystick motions. As a failsafe, I used the same hex codes from a TV remote I had at home for the up, down, left, and right buttons. This way, I could also use my TV remote to control the motors with the same codes. I programmed the motor PCB to receive the IR codes from the controller. In the code, I mapped the controller motions to the motion of the propellers. For forwards, I had both of the side motors go forwards, and opposite for backwards. For right, I had the left motor go forwards, and the right motor go backwards, and opposite for left. For up and down, I had the vertically oriented motor go forwards or backwards.

I tested my code with the joystick controller.

I was also able to control the motors with a regular TV remote.