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misiu
02-28-2008, 08:01 AM
I am trying to help a friend with a UAV project. We have solved the majority of the issues with flying the vehicle. However getting an effective orientation of tilt in multiple directions has proven a challenge

Any suggestions on an inexpensive gyro or some sort of tilt sensor that would interface with a PC. It needs to be effective on a vehicle that has a 80+ inch wingspan and is 50 inches long.

I Was even debating hacking apart a digital carpenters level and trying to interpret thouse signals but... Dont think it would work

misiu
02-28-2008, 08:54 AM
http://www.smarttooltech.com/product.php?product=4

actually mabye something like this would work?

MYKL
02-28-2008, 12:22 PM
Or you could use this:

http://www.trossenrobotics.com/store/p/5160-PhidgetAccelerometer-3-Axis.aspx

It would help keep it stable too.

With that kind of wingspan it would take a brisk wind, Unless your UAV is really light but having the insurace is good. You have to account for differing currents and temperatures as the machine moves toward its target.

misiu
02-28-2008, 12:45 PM
I looked at the trossen robotics 3 axis sensor. I just didnt know if it would be sensitive enough. Either way im going to be giviing it a shot.


Its actually going to be run off of a 1.5 megahertz via embeded motherboards 5.2 inches x 5.2 inches a gig of ram and a 8 gig solid state drive running windows XP

for direction a digital compas and a GPS receiver

So provided I can get a good pitch/roll reading I should be able to programaticly adjust for any deviation from set elevation, direction,

At this point though there is a problem of having enough electric power to run everything. To solve that were going to be running a modle alternator from www.sullivanproducts.com (http://www.sullivanproducts.com/). Should provide enough juice (although this isnt tested yet)

Matt
02-28-2008, 05:14 PM
Whoa, you are making a UAV big enough to carry an ITX? Awesome. I'll be very curious about how real time your response is with your sensors and OS. Are you running a really light weight linux OS or something else?

As you probably noticed we carry a line of accelerometers & gyros:
http://www.trossenrobotics.com/store/c/3087-Accelerometers-Gyro.aspx

But I would also suggest checking out sparkfun since they have a larger selection:
http://www.sparkfun.com/commerce/categories.php?cPath=23_80
http://www.sparkfun.com/commerce/categories.php?cPath=23_85

misiu
02-28-2008, 06:32 PM
Sadly were going to be trying to run windows first. there is enough proccessr/memory to make it happen.

1.5 Gigahertz (i know i wrote Megahertz earlier but I was on a conference call with 30 people I had shut my brain off sorry)
1 gig of ram
8 gig solid state hard drive.

I cant think of any thing I would do program wise that would require a more powerful system then that. Supposedly it only draws 15-20 watts

At the moment the plan is actually to setup a wireless network at the field and jus have the wireless card in the UAV join the network and fly it from a laptop initialy to gather data from all the sensors.

The goal is to have it be able to take off by its self, fly out about 50 miles hit some waypoints, take some pictures, and come back. Require the airfield signal and land it manually until we can figure out a way to teach it to do it itself.

a slightly ambitious project i know :-) Im not even going to mention the long range goal you all will think im crazy.

Adam

Alex
02-28-2008, 06:51 PM
If you're going to be running Windows, you may want to look into getting a slightly larger hard drive if the funds permit. An 8GB HD isn't that large for Windows. When Windows has less than like 5GB or so free HD space (depends on the size, number increases as total HD space increases), it starts to run like crap.

DresnerRobotics
02-28-2008, 06:59 PM
If you're going to be running Windows, you may want to look into getting a slightly larger hard drive if the funds permit. An 8GB HD isn't that large for Windows. When Windows has less than like 5GB or so free HD space (depends on the size, number increases as total HD space increases), it starts to run like crap.

8 gigs is plenty :P

Just strip out the unneeded crap (I've had a windows xp footprint under 700 megs) and turn off your page file, or limit it to 1 gb, and thats a good amount of free space for programs/code. The OS my J5 is running is only about a 900 meg footprint (I left a bunch of extra stuff in it) and uses about 65 megs of ram. I am the windows stripping ninja! :D

MYKL
02-28-2008, 07:31 PM
I would think that the fact that he's using a solid state drive would negate a lot of the performance problems that normally occur with windows as far as disk space is concerned.

Aren't those things uberpricey?

DresnerRobotics
02-28-2008, 07:46 PM
I would think that the fact that he's using a solid state drive would negate a lot of the performance problems that normally occur with windows as far as disk space is concerned.

Aren't those things uberpricey?

They can be pricey. Most of them aren't too much faster then an IDE drive as far as data transfer rates go, it's just that they have essentially no seek time and aren't prone to vibration damage.

misiu
02-28-2008, 08:02 PM
The vibration damage issue was huge. We needed something that wouldn’t break the first time we landed a little rough. That and they require less power than a normal hard drive. Most of the performance gains you get from solid state are lost because most of them at that size are still an IDE interface not SATA

The 8 gig solid state drives go for about $250 give or a take a bit.


We have a long way to go on the project. At the moment it’s looking like an 86'' wing span, twin engine amphibious model. The plans (hopefully) should be here next week. I briefly debated designing my own but... I just don’t have the skill for it, or any good 3d modeling software.

Initially the first attempt it’s just going to be trying to work out the challenges of UN manned flight. UAV part two will be a much larger version hopefully capable of carrying 300 lbs in a 100 mile round trip... why 300?... well mainly because I’d rather spend a few thousand on something interesting then getting drunk in the bar on the weekend. That and I was recently given the “if you don’t sell the motorcycle you’re sleeping on the couch ultimatum”. Somehow im allowed to mix homemade rocket fuel…. But riding a motorcycle is not safe enough??? Someday someone will explain women to me.

Alex
02-28-2008, 08:08 PM
The OS my J5 is running is only about a 900 meg footprintNice! You busy this weekend? I need to reinstall my OS and I'd love some tips to keep Windows from hogging up all my resources:)

edit: Sorry for hijacking the thread. Posting while watching TV and listening to friends talk don't mix well;) Just PM me.

Matt
02-28-2008, 08:17 PM
This is a good idea for a fresh thread, to have a thread about how to strip windows down. This would come in handy for A LOT of bot builders. Maybe something to start over in the brains of my robot forum.

[you may now return to your regular programming :D]

misiu
02-28-2008, 08:22 PM
You should really look into a embeded windows system . Pre stripped down and somewhat limited but very stable with much less hardware reqs.

Although windows xp service pack 3 supposedly is going to drasticly improve performance.

cmmguy
02-29-2008, 12:28 PM
I am trying to help a friend with a UAV project. We have solved the majority of the issues with flying the vehicle. However getting an effective orientation of tilt in multiple directions has proven a challenge

Any suggestions on an inexpensive gyro or some sort of tilt sensor that would interface with a PC. It needs to be effective on a vehicle that has a 80+ inch wingspan and is 50 inches long.

I Was even debating hacking apart a digital carpenters level and trying to interpret thouse signals but... Dont think it would work

You will need a real gyro to get feedback on plane orientation.

During a coordinated turn, the forces in a plane can be identical to straight and level flight. So you might not be able to tell the difference. That effect has killed quite a few pilots who fly into IFR conditions accidentally.

300lbs-100 mile round trip hmmm.... not planning on a border crossing are you??:veryhappy:

misiu
02-29-2008, 01:06 PM
Lol no no border crossing. Although I bet I could sell it for alot of money to someone who was interested in that... hmmmmmm...

No the purpose behind it is that the family that has an Island in the bahamas we used to rent out. And were starting to rent out again. Its about 50 miles from civilization and I was looking for an inexpensive way to get supplies (groceries) out there.

A 30 foot boat with twin 250's on it burns about 1 gallon of gas per mile at a cruising speed of about 38 mph.

So when you factor in having to go around islands, shallows, etc. you burn about 65 gallons of gas per one way.

with gas prices in the bahamas your looking about $250+ per one way trip or $500 round trip.

So im thinking I can make the trip for less then $40 per one way with the UAV

Alex
02-29-2008, 03:07 PM
That's showing some ingenuity! A real life application using robotics for a real life problem:D

I wish I could help out more with this, but most of it is pretty far over my head... Just wanted to chime in on how creative this idea is.