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Old Nov 03, 2012, 04:32 PM
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Uk South Wales
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SkyCadet has the answer, the science is a bit obscure but basically there is a solid state chip that measures angular rate by measuring the change in vibration of a crystal on the chip. there are 3 on this unit aligned to measure the 3 axis of rotation. So whilst technically there is a moving part it is a small crystal vibrating microscopically small distances, not like the old spinning top type of gyro from back in the day. all you see is a circuit board with some chips on it.

here is a pic of a quad copter gyro board (easier to see) you can see the 3 gyro 'chips' clearly (3 silver boxes align 3 different ways)

Dave
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Old Nov 03, 2012, 09:08 PM
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Canada, MB, Winnipeg
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I thought so. The piezo crystal vibrates and any inertial changes to the board affect the resonant frequency of the oscillator. A phase sensing circuit or other similar system must do a doppler shift measurement to determine the relative rate of motion.

Cool. Amazing what technology we have nowadays!

I've dealt with piezo oscillators in one of my other hobbies, Amateur Radio. So I have pretty good electronics background. I had heard that these gyros had piezo units in them just did not know for sure what made them tick. However, the other option could be like what we see in micro balances: A piezo crystal generates a voltage due to force on the faces (piezo electric effect). Maybe a small change in voltage is read directly without oscillation? However, the oscillation option makes more sense as it's easier to measure VERY small relative changes in a frequency compared to a nanovoltage, which may be subject to noise (motor/ESC/RX/Servos, etc)

SkyCadet/VE6IZ
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Old Nov 03, 2012, 09:36 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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You will find some good info on this site. These are they guys who make the sensors. Browse around and you will find papers on design and how they work.

http://invensense.com/index.html
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Old Nov 03, 2012, 09:49 PM
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Carmichael, CA
Joined Feb 2007
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Peizo gyros are neat (Murata), but mems gyros (Invensense) are equally amazing, with their complex structural modes and closed loop feedback systems. Far cry from the true mechanical gyros of the 80's... that were like a toy gyroscope with spring and a poti attached LOL!

Kev
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Old Nov 04, 2012, 12:13 AM
Bladerex700
Joined Jul 2007
422 Posts
Ok, I put mine today in my slywalker, but I can't get it to be set up correct, everytime I connected one of the servo extension wire, from the tx receiver, Aux 2 to the orange stabilazer, the receiver will not respond, But if I unploged, the two aileron respond at the same time on the same direction, I also have tried to change or reversed the Chanel and to luck,

Any idea what could be?
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Old Nov 04, 2012, 01:53 AM
Bladerex700
Joined Jul 2007
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Here is an other thing, I am using the eagle tree system, and I lost my artificial horizon, why?
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Old Nov 04, 2012, 01:56 AM
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Canada, MB, Winnipeg
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I assume that your RX is running Aux2 for the second aileron?

Try this:

Use Only ONE aileron channel to the Orange and tie the two aileron outputs to the respective ailerons. You may have to toggle the reverse switch and may even have to reverse the TX aileron channel direction.

So go from the RX outputs to the ORX unit, then to the servos. Just make sure that Inputs and outputs are correct. Follow the labels on the ORX to verify the correct slot for the servo connections and you should be fine. Also, dial down the gains on ALL axes fully counter clockwise (to the left) to minimize gains until you confirm directional control from the radio.

Then start around the 1-o'clock to 2-o'clock position on all axes as starter points for adjusting the stabilization gains. tweak slowly either way from this point as they are most sensitive. No idea about the FPV portion of issues. sorry.

Let us know how you do! Good luck

SkyCadet`
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Old Nov 04, 2012, 03:35 AM
Mark Harrison
USA, CA, Piedmont
Joined Jun 2010
2,269 Posts
Quote:
Originally Posted by SkyCadet View Post
I thought so. The piezo crystal vibrates and any inertial changes to the board affect the resonant frequency of the oscillator. A phase sensing circuit or other similar system must do a doppler shift measurement to determine the relative rate of motion.

Cool. Amazing what technology we have nowadays!

I've dealt with piezo oscillators in one of my other hobbies, Amateur Radio. So I have pretty good electronics background. I had heard that these gyros had piezo units in them just did not know for sure what made them tick. However, the other option could be like what we see in micro balances: A piezo crystal generates a voltage due to force on the faces (piezo electric effect). Maybe a small change in voltage is read directly without oscillation? However, the oscillation option makes more sense as it's easier to measure VERY small relative changes in a frequency compared to a nanovoltage, which may be subject to noise (motor/ESC/RX/Servos, etc)

SkyCadet/VE6IZ
These aren't piezo, these are MEMS gyros... from amazing to astonishing, especially when you consider the price we're paying.

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Old Nov 04, 2012, 03:50 AM
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Australia, QLD, Regents Park
Joined Mar 2007
3,732 Posts
In a boat

I posted a short while ago asking if these were any good for a boat stabilizer, I'm reporting back and saying this is awesome for the application It works even better than I expected, I can see how a system with more sophisticated sensors would have the advantage as there were a couple of times I noticed it actually inducing a slight lean but I'm well happy.

Cheers
Nick
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Old Nov 04, 2012, 07:51 AM
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Uk South Wales
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Quote:
Originally Posted by nick_75au View Post
I posted a short while ago asking if these were any good for a boat stabilizer, I'm reporting back and saying this is awesome for the application It works even better than I expected, I can see how a system with more sophisticated sensors would have the advantage as there were a couple of times I noticed it actually inducing a slight lean but I'm well happy.

Cheers
Nick
I used one on a yacht for a sort of autohelm and it worked great, no more crewing into wind just set it on a heading and then fine tune the sail as it goes........the local boat club said I would however be excluded from competition......lol well I suppose until they all get one.....

Dave
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Old Nov 04, 2012, 07:57 AM
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Uk South Wales
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Quote:
Originally Posted by aisamac gomez View Post
Ok, I put mine today in my slywalker, but I can't get it to be set up correct, everytime I connected one of the servo extension wire, from the tx receiver, Aux 2 to the orange stabilazer, the receiver will not respond, But if I unploged, the two aileron respond at the same time on the same direction, I also have tried to change or reversed the Chanel and to luck,

Any idea what could be?
You have the aileron servos on your plane connected to 2 outputs on the RX, maybe you have differential set up or something? If thats the case then sorry this unit doen't support that type of setup. you will have to run a link from the AIL on the RX to the AIL IN on the ORX then have a 'Y' lead to the 2 servos........it is just a basic model so doesnt support all those fancy mixes.

The secon AIL output is actually reversed so when you connect your servos they will both go the same way, its a bit of an odd setup no one knows why they did it........

There are more complex and costly units out there that will support 2 separate AIL servos to allow mixing for differential, crow braking etc.

Dave
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Old Nov 04, 2012, 08:19 AM
Bladerex700
Joined Jul 2007
422 Posts
So technically speeking, no mater what, I will have to run a (Y) connector for the two ailerons to run propertly,
Thanks Dave,

Aisamac
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Old Nov 04, 2012, 08:23 AM
Bladerex700
Joined Jul 2007
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Quote:
Originally Posted by SkyCadet View Post
I assume that your RX is running Aux2 for the second aileron?

Try this:

Use Only ONE aileron channel to the Orange and tie the two aileron outputs to the respective ailerons. You may have to toggle the reverse switch and may even have to reverse the TX aileron channel direction.

So go from the RX outputs to the ORX unit, then to the servos. Just make sure that Inputs and outputs are correct. Follow the labels on the ORX to verify the correct slot for the servo connections and you should be fine. Also, dial down the gains on ALL axes fully counter clockwise (to the left) to minimize gains until you confirm directional control from the radio.

Then start around the 1-o'clock to 2-o'clock position on all axes as starter points for adjusting the stabilization gains. tweak slowly either way from this point as they are most sensitive. No idea about the FPV portion of issues. sorry.

Let us know how you do! Good luck

SkyCadet`

I think I might end up with a (Y) connector in order for me to avoid any headaches,

Thanks

Aisamac
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Old Nov 04, 2012, 09:09 AM
Canadian Bacon
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Kingston, Canada
Joined Jun 2004
13,173 Posts
I thought I read where it was a built in Y connector. Try plugging an ail servo into each one of the Ail outlets and see what happens.

Gord.
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Old Nov 04, 2012, 10:35 AM
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Canada, MB, Winnipeg
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Yes that's what I figured too. He needs to use one output off the RX to run the ailerons differentially.

SC
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