just to precise, the gyro
just to precise, the gyro are almost always rate gyro, so they don’t tell you which way are you ponting, but just how fast you are turning. For examle they can say “you’re not turning” or “you are turning 5° per second”, but they don’t tell you “you’re pointing 45°”
Oh yes… erh… well. some
Oh yes… erh… well. some have a "memory" that you use to get the angle out. But you are of course right, the very gyro itself (if one of the new fancy ones with pulsing and stuff, and not the old fashioned kind with a motor spinning a disc) - the very gyro does not remember where it is tilted to. Something else must overlook the gyro and keep track if your current angle is what you are interested in.
Both or either
Well, with the correct mechnical arrangement, rate gyros and acelerometers can give complimentary information. I thought TCG was asking why one would use both together (eg in applications such as a co-axial wheeled robot)…
Indeed
Infinitely flat, you might say!!
Big Smile
You’ve brought back memories from 20 years ago.
I’m amused by this thread, and will follow it. From personal experience, I can tell you that a condom will hold a large volumn of helium. Enough to lift sereral ounces at least. In our “experiments”, we taped pennies to them for ballast and balance, so they’d stay somewhat level, and crepe paper steamers for visual effect. (With creative graphics drawn with permanent markers).
We were flying our “Trojan Blimps” inside a factory production room (on the mid-night shift) which had an accoustical tile ceiling, about 25 feet high. They were subject to the slightest air movement. We could sort of “control” thier flight with blasts from compressed air hoses from floor level.
I don’t really know how long they would hold the heluim before it leaked out, because the longest that we had one last was just a couple of hours. Eventually they’d bump into something and go “POP”. Either that, or get shot down by an opponent, using a rubber band and paper clip. Fish hooks were also used sometimes.
We’d have 6, 2 man teams, with 6 “Blimps” going at a time. It was great fun.
So, a condom WILL fly. But, trust me, it is NOT very durable.
I’m sure that management would have frowned on our hi-jinks, but as far as I know, they’ve never found out about it.
The closest that we came to getting caught was when Mark, AKA “Big ■■■■”, got a treble fish hook stuck deep in his finger, and had to go to the Emergency Room to have it removed. That was the wildest, most fabricated safety incidence report that I’ve ever known of. “So how did you get this fish hook stuck in your finger?” “And why was it attached to a rubber band?”
Duane S
Wilson, North Carolina USA
lol, duane that was a very
lol, duane that was a very nice story 
i’d like my workplace to be just half that fun…
Yeah, I agree. I wish that
Yeah, I agree. I wish that my current job was as much fun. We were able to do things like that because we had a lot of idle time, and needed the distraction to keep from going crazy.
During a midnight shift, we’d go from boring periods where 4 people could run the entire operation, to frantic periods where we needed 50 people, but didn’t have them.
The best part was that our crew was able to set several production and quaility records while engaged in these kind of distractions, and upper management never had a clue about how we did it. And we were not telling. Our standard answer was “good teamwork”.
Duane S
Wilson, North Carolina USA
Sometimes you read what your
Sometimes you read what your mind tells you, guess what I read here:
"I can tell you that a condom will hold a large volumn of helium."… "we taped pennies to them for ballast"
Well… it was not the word pennies that I read 
don’t use condom…
in fact dont use anything that is elastice like balloon meteorologic ballon, ect. anything that is flexible is very bad for aerodynamics, use “aluminzed nylon” instead it’s most time called Mylar but it’s not. you can make your ballon by sealing it with an iron.
I’ve did a lot of research on that field and aluminized nylon is the best you can get.
rc balloon
I have a fresh balloon from a blimp. not sure exactly how big, but probably strong enough. not sure how to attatch anything to it
Do some maths, even if you hate it.
I’m working on a blimp for about a year and a half now, all I could say is make your robot, then wheigh it, then think about the enveloppe (balloon) volume, do some maths, 1cubic meter of helium may lift 1kg but it’s at room temperature at sea level, make sure everything it’s just a rule of thumb.
Hydrogen and other idea
Can’t you fill the blimp with hydrogen?
It’s not like there is going to be a fire in the sky!
You can also generate your own hydrogen with electricity and salt water.
This cut’s the price of the gas down.
And can’t you use an ultrasonic sensor for height mesurments?
Then you only need to consentrate on gps.