View Full Version : Attack of the giant robot airships!

Sir Penguin
03-02-2006, 06:05:27
I'm taking a mechatronics class this semester, and we're making robot airships for the opening of the new computer science building in April.


Here, a team member and I are testing the blimp gondola's built-in control system. The idea is to use a 68HC11 microcontroller to translate joystick movements into signals to the remote control, which will transmit the signals to the gondola. To regulate the airship's speed, we needed to implement pulse-width modulation, and to do that, we needed to detail the pulse shapes we could use. It turns out that the crummy gondola controller could only take 1.5 Hz at an 80% duty cycle, which is terrible. Anything beyond that, and it would struggle to keep up. Interestingly, there's a button on the radio controller that is supposed to make the gondola lights flash. It puts the gondola controller into some sort of polling loop, which allows us to use better than 8 Hz at full duty cycle. Hooray!


This is the final wiring of our control system. The joystick has three wires, for the X, Y, and Z controls, going to the microcontroller (there are two other wires, for +5 and GND, which go to the corresponding rails on the breadboard). The microcontroller translates the joystick coordinates into motor impulses, and activates up to three out of six circuits on the breadboard. The six wires coming out of the 6811 connect to six isomorphic circuits on the breadboard. Each circuit has a current-limiting resistor between the 6811 and an NPN transistor. When the 6811 outputs high on a line, it activates the transistor, which completes the circuit between the corresponding radio controller switch and ground. The six switches are for left forward/backward, right forward/backward, and up/down. Eventually, we will do away with the joystick, and control the blimp with software onboard.


This is likely to be the blimp style we'll use. The other option is two of the silver rounded balloons you can see in the back, tied together. We also have a couple smaller, silver hot-dog shaped balloons, but they don't have enough lift to carry all of our instruments.


In the background, you can see one of the silver hot-dog shaped balloons. We set that one up to float perpendicular to its natural orientation, by taping the gondola to the ass-end of the balloon and ballasting it with bits of CAT-5 cable. It was hard to fly the thing that way. On the blimp in the forground, you can see something like what the blimps will eventually look like. Near the front of the gondola (the end with the vertical motor), on a piece of corregated plastic that we're using to hold the instruments, you can see one of the sonar units we'll be using to track distance. There will be two or three sonars (depending on how much the blimp can lift) on the final model, to keep the blimp at a consant altitude, and to detect collisions. On the other end of the plastic is the MicroCore11 controller, which will be connected to the sonars, a magnetic compass IC, and a radio transmitter. Eventually, it will also control the motors, and maybe the lights if we feel adventurous.


03-02-2006, 06:15:14
My word, how long is that thing going to be around? That's what I was trained on in an intro EE class ten years ago, and I seem to remember it was old then...

Otherwise, :beer:

03-02-2006, 06:20:05
I am so going to end up working under you when you become a CEO somewhere.

03-02-2006, 06:30:00
Hmmm, a Flight Stick Pro. Made with pride in San Diego. Or at least it was until the fuckers closed the factory and moved everything to China. :angry:

Sir Penguin
03-02-2006, 06:44:20
Is that the grey joystick? We had to adjust a bunch of the wiring inside, and bypass the buttons, because they were multiplexed. It's a good joystick though, it has a rocker that we use for vertical control (the other groups have up and down buttons that they trigger manually).

The 68HC11 is a wonderful piece of equipment. Up until last year, the second-year computer science architecture course used the BLT-11 boards (they use MIPS32 now). It barely has enough input and output ports for our purposes, but It's got the A/D converter, serial port, and all that, which is really all we need. There's even a multi-threading operating system for it that we'll use for the final model.


Sir Penguin
03-02-2006, 06:50:58
I'm not sure when the 6811 was introduced, but Wikipedia says that the 6812, a more powerful version of the 6811, was introduced in 1990.


03-02-2006, 10:40:22
I can't see the pictures. :(

03-02-2006, 13:07:18
Terrifying Red X blimps.

03-02-2006, 13:20:36
sp: ultimate science geek, but can't link pictures for shit

03-02-2006, 13:26:55
I'm not geek enough to see the pictures.

Sir Penguin
03-02-2006, 18:08:43
I can't believe four people can be so incompetent at seeing simple pictures.


03-02-2006, 18:15:53
you should make tiny scale models of football stadiums to fly it over

Sir Penguin
03-02-2006, 18:25:55
:lol: We were actually thinking of selling advertising space on the blimps.


03-02-2006, 19:35:04
silver hot-dog shaped balloons silver hot-dog shaped balloons silver hot-dog shaped balloons

Sir Penguin
06-04-2006, 22:23:57
Here's the latest video:


It interfaces with my laptop through a Bluetooth serial connection. We can control it manually over the serial terminal, or upload a set of commands. There are still some bugs to work out, but it does more or less what it's supposed to.


06-04-2006, 23:06:58
I find the Richard Branson Lands Himself vid more interesting. It would be even more interesting without Branson in it and with the two girls as lesbian whore nymphomaniacs - but you can't have everything...

06-04-2006, 23:12:41
This is soon to be the result of these preceedings:


07-04-2006, 00:15:16
Only if they fill it with one of Venom's farts...

07-04-2006, 00:52:19
Oh the photoshopped penis!

Sir Penguin
07-04-2006, 01:33:23
We use helium. :coolgrin:


07-04-2006, 07:11:08
the one with the white shirt is that your twin brother?

Sir Penguin
07-04-2006, 07:29:34
You mean the guy who doesn't look anything like me except for the fluroescent light tan?


07-04-2006, 07:40:51
jesjes and the hairy arms the glasses etc.

07-04-2006, 07:58:37
I watched 2.5 minutes of that video... did anyone manage longer?

07-04-2006, 14:33:55
So can you make it move backwards and forwards, and sideways?

07-04-2006, 14:36:53
OMG! Geeks!!!!

07-04-2006, 17:09:43
I managed to watch it all. It was a bit less boring then CG.

07-04-2006, 17:16:18
no way!@

Sir Penguin
07-04-2006, 18:48:53
Originally posted by Drekkus
So can you make it move backwards and forwards, and sideways?
We can't move it sideways unless we blow really hard.


Immortal Wombat
07-04-2006, 18:51:35
Or if you suck really hard.

07-04-2006, 20:17:19
They all suck and blow

10-04-2006, 10:57:42
Oh, the tiny manatee!!!