nomocom

nomocom

Well Known Member
Ok so the iphone 4 may drop a few phone calls due to the antennae location:D but this new version has 3 axis gyros unlike previous models with accelerometers.

There is at least one group working to make a useful backup instrument.
"Airplane Gyroscope Attitude Indicator" by a pilot, Leland Roys, is available on the iTunes store for a buck.

Here's a link to his app support site http://www.caffeinatedconsulting.com/aircraft_gyroscope

A few years ago there was a fairly long thread discussing an AI with the iPhone 3. www.vansairforce.com/community/showthread.php?t=18357
At least a few concluded that it just wasn't going to happen without gyros.

So is this a game changer? I've got the iphone 3, so I can't usefully contribute other than ask the question. Anybody with a iphone 4, a buck, and some curiosity?
 
got it!

Just DL it and works pretty good in the house with accurate elevation but got it to tumble once with an outside loop.... Compass accurate also... If WX cooperates will take it for a ride this afternoon...

Fun stuff!!!
 
The iHUD app currently does not support the gyros, but I have exchanged emails with the author and he says it's coming in a future update. He says the data Apple let's you access through the "Apple approved" hooks isn't adequate on its own, but by applying certain filters it is possible to get useful data for an EFIS display. I don't know that id trust it for tracking me through a loop or roll, but for cross country trips it might be pretty cool.
 
Quickie test flight

nomocom said:
Ok so the iphone 4 may drop a few phone calls due to the antennae location:D but this new version has 3 axis gyros unlike previous models with accelerometers.

There is at least one group working to make a useful backup instrument.
"Airplane Gyroscope Attitude Indicator" by a pilot, Leland Roys, is available on the iTunes store for a buck.

Here's a link to his app support site http://www.caffeinatedconsulting.com/aircraft_gyroscope

A few years ago there was a fairly long thread discussing an AI with the iPhone 3. www.vansairforce.com/community/showthread.php?t=18357
At least a few concluded that it just wasn't going to happen without gyros.

So is this a game changer? I've got the iphone 3, so I can't usefully contribute other than ask the question. Anybody with a iphone 4, a buck, and some curiosity?
Click to expand...

I test flew it today in my -6a and it has a very long way to go to be "real"
Just a few flaws I noted....

Compass wildly out of sync with reality

The "Horizon" went TU a couple of times showing turning instead of level.

Teensy numbers unreadable to old eyes.

Interestingly, in my car showed a right bank while turning left...

Hope the author fixes things and am surprised he released with all the flaws.

YMMV
 
nomocom said:
So is this a game changer?
Click to expand...

Yes, it is.
This is technically not multiple gyros. It is a single vibrating proof mass but ST Microsystems, the makers of this device are deriving all three axis of rotation from this single mass. By doing so, they have completely outclassed the previous champions (Analog Devices) and even more to the point, the new chip is around 3-4% of the price of the three lowest cost gyros previously needed. Because of what they achieved here, ST currently has hero status in my book.
So is it any good ?
Kind of. It has some points which are better than the AD gyros but also some points not so good. Can you make an AHRS suitable for an aircraft with this ?
Yes, you can. But it ain't quite as easy as it may seem.
Like the AD gyros, these devices have many flaws that on first look make it near impossible. You have to throw not only some real clever software at the problem but you also need to still calibrate the system very carefully and accurately. There are many things that affect the accuracy of a gyro and it has many errors. Each of these need to be identified, measured during production and then compensated for by the software (and every gyro is unique). However, once you do that - things start looking quite good.
For the iPhone, the only real way is to discard Apples API and access the device natively, run it at maximum possible sample rate (that is important to help get rid of one of the more nasty problems) and then apply all the clever software after you have measured the performance of each axis in great detail so you are able to cancel out the errors. You do that and you have a useful product.

For its intended use on the iPhone (games), the uncalibrated chips are just fine as all you are looking for is to see if you just rotated the thing - you are not trying to track how you are rotating relative to your horizon (that needs great accuracy and every tiny error accumulates quickly and just gets bigger fast). For a game you need short term rotations and you could not care less if you just rotated the thing by 45 or 47 degrees. For this the chip is excellent right out of the box. For an AHRS you need to track tiny rotations at less than the noise floor of the device most of the time with very good accuracy, yet be ready to respond with equal accuracy to a sudden 100 degree per second or more rotation (proportioned over all thee axis !!!).
Then you might be flying along in real bumpy conditions (continous rotations around all axis) superimposed by a poor mounting (airframe shocks) and engine vibrations that also affect your gyros.

Possible - yes, absolutely. Easy ? Yea, right !

I don't know how long its going to take until the first iPhone app will give you good performance (it will one day, no doubt).
But guess what - we are already flying these things, no, not in a iPhone...

Rainier
CEO MGL Avionics
 
Rainier,

I sure wish you were local, I would like to just sit and chat with you for a while in hopes that just some of your intelligence and common sense would rub off on me!!!
 
As Rainier pointed out, game controllers and aircraft instruments have different needs. We tend to get cranky if our AI starts leaning when the plane isn't and low cost gyros can have some rather scary drift specs. Enter aiding! Another "eh, whatever" game vs. AI issue is performance under environmental exposure, like vibration and temperature. Analog Devices caters to this more with balanced dual and quad sense elements to help null some of these unpleasantries. This increases the amount of silicon used and therefore the cost and size of their chips. Also, the cost of test equipment (multi-axis rate tables) and the time to properly calibrate an AHRS adds a lot of cost to a "real" product. Still, it is interesting to watch the developments of the hobbyist UAV crowd on the various forums. Exciting stuff.
And yeah, your brain can quickly get full when you start really digging into this stuff. Google "quaternion".

"I can't brain today, I caught the dumb.":confused:
 
I don't see a blushing smiley as option so I'll just say you have me blushing.
But seriously, I'm pretty much just a normal bloke - at least I hope so, you'd likely be disappointed.

We had Chuck Yeager come for a visit to our flying club a short while back (he is having a holiday in South Africa).
Now THAT is different...

Rainier

Brantel said:
Rainier,

I sure wish you were local, I would like to just sit and chat with you for a while in hopes that just some of your intelligence and common sense would rub off on me!!!
Click to expand...
 
Just to give a basic idea what we are talking about.
This image shows the single proof mass three axis gyro as seen by an electron microscope. Note the extreme, fine detail of this micro-machined piece of silicon. This is true state of the art stuff.

Note that this is actually moving (vibrating) during operation.

Rainier

gyro.jpg
 
While yes, Yeager is a hero that I would love to meet, you my friend are obviously very educated in the world of electrons/embedded hardware/custom software that I have spent my entire life learning about....your smarts come thru clearly in your communication without you even knowing it!

Rainier Lamers said:
I don't see a blushing smiley as option so I'll just say you have me blushing.
But seriously, I'm pretty much just a normal bloke - at least I hope so, you'd likely be disappointed.

We had Chuck Yeager come for a visit to our flying club a short while back (he is having a holiday in South Africa).
Now THAT is different...

Rainier
Click to expand...
 
For those of you who are interested in this stuff, take a look at www.diydrones.com There are quite a few different open-source autopilot/inertial measurement units that are available and are surprisingly accessible to fiddle with, learn and have fun.

OK, I admit I spent some money that could have bought me my LED taillight/strobe and it does keep me from rivetting sometimes, but it is **** good fun and very educational!

When I get the chance, the system that I'm fiddling with is hooked up to X-Plane 9 and is flying an RV-8 in a hardware-in-the-loop simulator. It took me only a couple of evenings to get this working.
 
nomocom said:
Anything that might attach to my Xtreme someday;) ?
Click to expand...

Yes, sooner than you think. We have just commisioned first production run of a new, very low cost AHRS based on the new gyro chip. We are probably looking at and of February for shipping. Test flights have been completed and we are VERY happy with the results.

We are now also looking to make a slightly more expensive (OK, wrong word - let's use "less cheap") version using three of these gyros for a true triple redundant, vote based AHRS (as double redundant is pointless).

These new gyros are so cheap it is opening doors that where closed due to high cost previously. This is why the earlier comment "Game changing" was so right on the mark.

Rainier
CEO MGL Avionics
 
I'm considering the Ipad for my plane and stumbled into this thread. Glad I did. I'm delighted to learn that MGL is planning a lo cost AHRS for use with their Extreme. I'm looking forward to that.

I'm also glad to learn of the iPhone Artificial Horizon app. It looks like it is making real good progress.

The thought that comes to mind, though, is that it would be nice to have a separate, aviation dedicated, bluetooth AHRS module using this new single mass chip. Such module could then be interfaced to the Iphone or Ipad or other bluetooth enabled display. Might require jailbreaking, but that has not stopped others from using aftermarket bluetooth GPS units.

--Jose
 
The lure of bluetooth/wireless is a bit of a red herring here... If you're using it in your plane where there's a ready power source (the alternator), you might as well plug in the iPad/iPhone to keep it powered at 100%. Since you're now wired anyway, you might as well wire the connection between the iPad/iPhone and your AHRS box. The AHRS box will be wired to ship's power too.
 
Radioflyer said:
Sure, but how do you get the external AHRS data into the iPad?
--Jose
Click to expand...

Like most of our stuff, we open the interfaces to the public so you will be able to use these things on anything you like provided somebody takes the time to interface to them. There are no stumbling blocks placed in the way on our side.

Rainier
CEO MGL Avionics
 
RE:eek:pen interfaces

Can't help but comment on this one. I've seen this "open interface" marketing in a few places before, also talked to you personally at one of the shows. Based on the information I gathered from you and your sales staff, I installed a RDAC-XD box into my RV-10 with all of the sensors it came with.
When the time came to actually connect to it, no one thought it was their business to share that information.

Several emails to you went unanswered. One of your staff members actually tried to help but couldn't find the right document, and basically told me to get lost.

After hooking up your rdac box to a logic analyzer found out that you're working with a non-standard baud rate of 1261bps. Nothing is going to read that unless you bitbang it, which is just plain wrong. In this case the "somebody takes the time to interface to them" is very much true.

Since then i figured out the protocol, but I'm just so frustrated with this thing, i will rip it out and use something else. Too bad, because I thought it was a clever box like many of the avionics you make. Without proper support or at least documentation it's very difficult to use your "open interfaces".

Regards,
Lenny
#40803





Rainier Lamers said:
Like most of our stuff, we open the interfaces to the public so you will be able to use these things on anything you like provided somebody takes the time to interface to them. There are no stumbling blocks placed in the way on our side.

Rainier
CEO MGL Avionics
Click to expand...
 
ipads and wiring harnesses.

Snowflake said:
With a wiring harness that connects your AHRS to your iPad.
Click to expand...

Currently only a couple ways to get custom data into your ipad:
1) jail breaking it, so you have access to the blue tooth and usb port
2) feeding the data in via the wifi connection.
3) some companies do a special connection in through the audio port. (probably not a fast connection)

I've played around with the first 2 options listed above.
The wifi connection worked pretty good for me. I took a wifi router and installed linux on it and was able to feed gps data and other data into my ipad app.

Now relating to gyros...
Here is a video of a open source project I was working on.
http://www.youtube.com/watch?v=a0_zop-GIK8
That was a while ago, and gyros have gotten better and cheaper since then.
Writing the kalman filter was the hardest part.
If anyone has interest in this let me know.

Chris.
 
You got the wrong end I think.
The RDAC is different - it's not open for the single reason that I never bothered to write a document for it. The reason for this is that this is a "grown" protocol that started with our very first Extreme EFIS (you don't know it, this is like 10 years ago). Since then things got bolted on and the result is not pretty from a protocol point of view. Not even the baudrate is a standard value since the original processor used in the original RDAC had a weird crystal frequency. It's just messy. In fact, by doing what you have, you have found out the exact reason why I don't want this one public. I'm sure you will agree with this.

For this reason we made a special RDAC called the RDAC XE. This version has a neat protocol, ran at 19200 baud, was open and documented and even came with a sample Windows interface program.

Guess what ?
Nobody wanted it (we only sold a few handful) so we dropped it from our range.

The current production RDAC simply is not intended or suitable for third part use, it is that simple. No malintent here.

But, we have a new RDAC in the works (two models actually, big one and a small one). These use the CAN bus and cater for engines up to 12 cylinders with lots of other interfaces.
This one will be open from the start.

P.S: Just yesterday I released the interface document for our autopilot servo...

Rainier
CEO MGL Avionics

Lenny Iszak said:
Can't help but comment on this one. I've seen this "open interface" marketing in a few places before, also talked to you personally at one of the shows. Based on the information I gathered from you and your sales staff, I installed a RDAC-XD box into my RV-10 with all of the sensors it came with.
When the time came to actually connect to it, no one thought it was their business to share that information.

Several emails to you went unanswered. One of your staff members actually tried to help but couldn't find the right document, and basically told me to get lost.

After hooking up your rdac box to a logic analyzer found out that you're working with a non-standard baud rate of 1261bps. Nothing is going to read that unless you bitbang it, which is just plain wrong. In this case the "somebody takes the time to interface to them" is very much true.

Since then i figured out the protocol, but I'm just so frustrated with this thing, i will rip it out and use something else. Too bad, because I thought it was a clever box like many of the avionics you make. Without proper support or at least documentation it's very difficult to use your "open interfaces".

Regards,
Lenny
#40803
Click to expand...
 
Artificial Horizon for iPhone/iPad

Just found this thread, which started with a quest for a good horizon app and thought I'd mention that there appears to be only one app that works as a reliable artificial horizon on the iPhone; it's called PocketHorizon. It has 5* reviews on iTunes and seems to have overcome the problems that plague all the others. You do need an external GPS for it to work well, though. Here is their website: http://logical-drive.com/pockethorizon/
 
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