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Stick shaker output from Dynon Skyview

BruceEicher

BruceEicher

Well Known Member
Just read the April Sport Aviation Hombuilder's Ingenuity, adding a stall warning stick shaker. I think this is a great idea. My Skyview AOA display is out of my field of view, the beeping can be ignored, so why not add another warning.

Here's the question; Is there a way to activate the shaker from the Skyview'ssystem AOA?

BTW: love the new features on the update! Keep them coming Dynon!
 
I read that article, too, and the first thought that came to mind was...if you're "shaking" (or rather, vibrating) the stick in an RV, isn't that shaking all of the *control surfaces*, as well, since they're connected via pushrods?

I don't know about anyone else, but I don't think I'd be comfortable with something rattling my ailerons and elevators around (and all of the linkages and rod end bearings and such).

Maybe it's not a concern, I dunno...but the beeping in my ears from the AOA on the Skyview is enough for me.
 
This could be done very easily by taking the serial stream out of the Skyview (or any other EFIS that outputs its AOA variable) and parsing it with one of the many cheap and easy to program micro controllers around. Build a simple output circuit to drive your stick shaker and WALA!
 
Brantel said:
This could be done very easily by taking the serial stream out of the Skyview (or any other EFIS that outputs its AOA variable) and parsing it with one of the many cheap and easy to program micro controllers around. Build a simple output circuit to drive your stick shaker and WALA!
Click to expand...

Been there, done that. I made a stick shaker for my rv-9a and rocket last year. It sniffs the serial stream from a Dynon, Garmin or GRT EFIS and generates a control signal to a vibration motor. Programmable thresholds allow me to set various shaking algorithms depending on AOA.

I developed a clamp mount for the stick, but I want to try it underneath my seat cushion as well, which brings the term 'seat of the pants flying' into a new perspective.

My current findings is that you don't want this as an AoA indicator... It should activate as a stall warning. A well executed landing should not activate the buzzer.

I shrunk the entire controller and motor driver into a 25- pin Dsub connector shell, which is a trademark of many of my designs. This thing is cheap to build, the most expensive parts are the clamps that hold the motor to the stick. I will post photos once tax season is over.

I will publish the 'Swizzler' design once my flight testing is done.
 
Thanks for the feedback

I look forward to your pics and plans Vern. I too was thinking that adjusting the stick shaker as a last stall warning would be best.

Thanks Michael, now I know where to find the motor. Any brand or model you might recommend? :p
 
If I were going to include a feature like that in my plane, I'd make it a small motor with an eccentric weight (common in certain, umm, small personal devices). I'd put it either in or very close to the stick grip, and write the firmware to give it repetitive, short pulses rather than a solid on/off state.

There are very small pager/phone vibrator motors available cheaply from various electronic surplus places like BG Micro, but they're probably too small to produce a useful tactile signal. A common 12 VDC "hobby motor" could easily be modified with an eccentric weight to do the job.
 
vlittle said:
.. It should activate as a stall warning. A well executed landing should not activate the buzzer.
.
Click to expand...

I cannot disagree more. A well executed landing SHOULD activate the buzzer. Otherwise you are touching down too fast, too flat.
 
On second thought

I would like to think my performance with HulaGirl is just fine without the said devices. :p
 
My first reaction when I post is usually less than well thought out, and maybe a bit on the smart alleck side. Did Aleck spell his name with two LL's?
Anyway, then the serious side comes out.
These are RV aircraft. They are tight, they are nimble, they are fast.
Driving, and I mean driving, an Airbus might mean a plethora of algorithms and devices is called for to protect the flying public from a hapless pilot.
Apparently even that won't prevent some pilots from falling from the sky.
Now, I love inventive thinking.... but some days it just seems to pass that common sense mark. A clunky 14 volt motor attached to the stick in my RV is just what we really don't need. If you can't see your lift reserve indicator... MOVE it. OK, I am going to go torque seal my mouth shut. You guys have a great weekend.
 
DaleB said:
If I were going to include a feature like that in my plane, I'd make it a small motor with an eccentric weight (common in certain, umm, small personal devices). I'd put it either in or very close to the stick grip, and write the firmware to give it repetitive, short pulses rather than a solid on/off state.
Click to expand...

That's exactly what I did, with about ten pulses per second. I also made it progressive as you get closer to stall.

I promise to give you guys all the details soon, please give me some time to get my head above water.

BTW, when I wrote the FIX protocol (Flight Information eXchange), both Garmin and Dynon agreed to adopt it, with minor variations. Although this was some time ago, the stick shaker was the device I had in mind when I was herding those two wildcats.

In the distant past, I developed a remote AoA indicator for Dynon and GRT EFIS systems. The Swizzler is the natural evolution of this.
 
I have some updates for you folks interested in this topic.

I've been flying with my stick shaker. I interrupt the 'buzzing' 5 times per second, which provides more of a shake. I also change the amplitude of the buzz depending on AoA, which can provide a progressive warning.

The amplitude and AoA setpoints are programmable (from a PC serial port), much like the V-Speed AoA indicator I did several years ago. In effect, this stick shaker is the haptic implementation of the old product.

I also have a Stall vane input for those without AoA from an EFIS. It's non-progressive, just on and off. Doesn't really need any circuitry in the simplest case... could just tie the stall switch to a motor!
 
vlittle said:
I developed a clamp mount for the stick, but I want to try it underneath my seat cushion as well, which brings the term 'seat of the pants flying' into a new perspective.
Click to expand...
And now i'm thinking of something I saw at a motorcycle show a while ago... the VibeRider. But that was intended for the passenger, not the driver. :p

I shrunk the entire controller and motor driver into a 25- pin Dsub connector shell, which is a trademark of many of my designs. This thing is cheap to build, the most expensive parts are the clamps that hold the motor to the stick. I will post photos once tax season is over.
Click to expand...
The cell-phone vibrate motors can't be very large... I wonder if it would be possible to take one of the switches out of an Infinity grip, and use the leads for that switch to drive the vibe motor... Then just put the control mechanism back behind your panel.
 
Most airplanes with direct linkage to the controls (and every RV I've flown) gives plenty of tactile feedback to the stick when you approach a stall.

Big airplanes, with controls insulated from the pilot due to boosted or outright hydraulic linkage, lack that direct "feel".

The stick shaker therefore was developed to simulate the feel of a "direct linkage" airplane at stall.

So if the shaker is an artificial simulation of the feel of a direct linkage, why add that feature to an RV when it already exists naturally?
 
Snowflake said:
The cell-phone vibrate motors can't be very large... I wonder if it would be possible to take one of the switches out of an Infinity grip, and use the leads for that switch to drive the vibe motor... Then just put the control mechanism back behind your panel.
Click to expand...

They're not very large, in fact probably too small to be really felt given the mass of the control stick and grip. I could be wrong, have not tried it, but I'd think you would need something a little more aggressive.
 
Toobuilder said:
No comment on specific brands, but you will likely find your local adult store has a large selection in the "aviation department". ;)
Click to expand...

They also have various stick grips with the buzzer already built in, which solves the issue of how to mount the shaker/buzzer. Might get a few odd looks at fly-ins, though. :eek:
 
Way too much material...

RBD said:
They also have various stick grips with the buzzer already built in, which solves the issue of how to mount the shaker/buzzer. Might get a few odd looks at fly-ins, though. :eek:
Click to expand...

She's a 'Girl, can't install unnecessary "hardware" :eek:

Weather's great, I'm going flying.
Cheers!
 
DaleB said:
They're not very large, in fact probably too small to be really felt given the mass of the control stick and grip. I could be wrong, have not tried it, but I'd think you would need something a little more aggressive.
Click to expand...

The motor I use is about 1 inch in diameter. It could fit inside the stick, but securing it is difficult. My clamping method works fine and I developed a cover for the eccentric spinning weight that will win an industrial design award. The algorithm for pulsing the motor does provide a nice feel, but a bigger motor would give a stronger feel.

I promise some pics soon.
 
vlittle said:
...you mean like dual EFIS systems for VFR flight? :)

Sometimes we do it because we can.
Click to expand...

OK, yeah... You got me on that one.

But its more like flying the synthetic vision screen on a severe clear day...

Or adding those little instrument "thumpers" jet aircraft use to keep the needles from sticking...

It's adding electrons to simulate what's there in nature anyway.

With that said, if a pilot of an RV is going to ignore the overt tactile cues their airplane is throwing off, then why would they pay attention to a little buzzer in the stick?
 
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Why stop there?

I can't help but agree with Toobuilder. Why stop with a shaker? Why not add a hydraulic system and a stick pusher while you are at it, just in case you ignore the feel, the AOA indicator and the shaker!

I think most RV pilots would be better off with one or two hours of dual time in a Pitts or Extra just doing stalls, straight ahead falling leaf and some spins and recoveries. Accelerated stalls in turns will build on that. It is easy to feel the onset. Even with no AOA or stall warning devices. Some dual time with a qualified instructor is like gold.
 
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rebuttal

I won't argue with any opinion here. However, I do appreciate facts.
The below article is taken from the AOPA web site.
http://www.aopa.org/asf/ntsb/stall_spin.html

Stall/spin myths exploded

Pilots who believe that aerobatic training will enable a recovery from an inadvertent spin in the traffic pattern are fooling themselves. That myth - and other misconceptions about stalls and spins in GA aircraft - is exploded in this new ASF study. This study is not intended to discount the value of properly conducted aerobatic and spin training. Training in a controlled environment with a trained instructor is beneficial. The most important aspect of the training should be recognition and prevention.

Stall/spin accidents tend to be more deadly than other types of GA accidents, accounting for about 10 percent of all accidents, but 13.7 percent of fatal accidents. Overall, around 20 percent of all GA accidents result in fatalities, but stall/spin accidents have a fatality rate of about 28 percent.

On a side note, an accomplished acro pilot stated that should he stall and go inverted at low altitude "at least he would know why he was flying into the ground vs. the average pilot wondering."

Regards,
Tony
 
Toobuilder said:
... if a pilot of an RV is going to ignore the overt tactile cues their airplane is throwing off, then why would they pay attention to a little buzzer in the stick?
Click to expand...

Because the little buzzer can be programmed to activate as a warning in advance of a wing buffet, even at high g loads where the time between buffet and stall is very short.

That's why AoA exists... all the buzzer is doing is replacing the visual or audio warnings.
 
Even before the tactile clues you can hear the wind noise over the main wing change as the AOA increases. The fingers, ears and brain are wonderful creations but most of us need to be shown how to use them to our best advantage. The only way to get used to the feel and sounds is to go there. The only smart way to go there initially is at a safe altitude with a qualified and hopefully gifted instructor.(Not in your RV) A good instructor can set up a base to final turn (at a safe altitude) and overload or distract the student, to the desired effect of the snap to inverted if he gets uncoordinated with the rudder. There is no finer tool to teach and ingrain extreme rudder co-ordination than a straight ahead and upright falling leaf. I would rather listen to the wing and wind than "Angle angle push" and I would rather feel uncorrupted pressures from the elevator and rudder pedals. But that is just me... No doubt AOA indicators are hear to stay. Just not in my AC.
 
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Am I missing something here......?

Did anyone consider that this may have been an April Fools joke :rolleyes:
 
mike newall said:
Am I missing something here......?

Did anyone consider that this may have been an April Fools joke :rolleyes:
Click to expand...

If they had of included a seat taser to fire right after the stick shaker I would have been with you on the April Fools joke. The body convulsion would force the stick forward....
 
Tony Rome said:
I won't argue with any opinion here. However, I do appreciate facts...

Pilots who believe that aerobatic training will enable a recovery from an inadvertent spin in the traffic pattern are fooling themselves....
Click to expand...

Let's put the stated facts in context-

The words above and the supporting article indicate a full blown spin hard to recover from TPA... I agree.

However, aerobatic and upset training serves to PREVENT a spin in the pattern. It does this by tuning your senses to listen to the very overt signs of an impending stall. And the more you practice, the clearer these signals come through. Pilots who stall and spin on purpose often DON'T stall/spin by accident, Period. I have flown with guys who blast right through the warning signs and obvious buffet without even realizing it. Meanwhile I'm sitting there with the airplane screaming loud and clear (to me) that it's about to depart. I'll bet Sean or Patty don't accidentally stall on base to final.

I guess it comes down to a choice of either tuning up your senses, or blasting through the dullness with a beeper, light or shaker. Given the choice between perfect hearing or a hearing aid, I'll go for good ears every time. And in the case of "hearing" your airplane, that is improved through practice.

It's going to take a few hours with a soldering iron to make this stick buzzer work... I think spending those same hours doing stalls instead would get you far further ahead.
 
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Toobuilder said:
MBig airplanes, with controls insulated from the pilot due to boosted or outright hydraulic linkage, lack that direct "feel".
Click to expand...

Careful...you'll give somebody the idea of replacing the pushrods and bellcranks with a fly-by-wire system just to justify their "stick shaker". :)

Still wondering what effect (long-term or short-term) "vibrating" or "shaking" the entire control system at a fairly high (for control surfaces/systems) PRF may have on all the components...
 
RV7A Flyer said:
Careful...you'll give somebody the idea of replacing the pushrods and bellcranks with a fly-by-wire system just to justify their "stick shaker". :)
Click to expand...

Or worse still, a Bluetooth linked fly by "wireless" :eek: joystick.
 
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Cool idea... use a side-mounted USB joystick, and a little PIC board to move the control surfaces with stepper motor actuators. Then you could have your choice of whatever kind of stick you want depending on your mood that day. Heck, you could even just use a couple of big EFIS screens and a Playstation controller and fly it just like a video game. Or how about this -- just a smart phone app using the acceleration sensors! Just tilt it to control the plane.

I kid, I kid!!
 
vlittle said:
Because the little buzzer can be programmed to activate as a warning in advance of a wing buffet, even at high g loads where the time between buffet and stall is very short.

That's why AoA exists... all the buzzer is doing is replacing the visual or audio warnings.
Click to expand...

Vern,
There is little doubt.
If you build it, they will come and buy it.

If the FAA took a liking to it for GA, you could end up with fuel in the rocket forever.

(Humm Humm---- Humm Humm, I wonder if that vibration is my wife calling, or the AOA increasing):)
 
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Here's a photo of the PIC board I used for the prototyping. It's actually a 2-channel servo motor controller with speed scheduling that sniffs a G3X, SV, D10A or GRT serial data stream.

The stick shaker version will be 1/2 of this, packed in the D-25 shell.

M-PWR-2.jpg


Can open, worms wiggling.
 
Update, here's the proto of the stick shaker controller. A pcb rev is required, but the firmware is all done and ready to test.

Edit: technical details: CPU is a PIC12F1822. PCB has extensive input/output protection and power surge protection. The optional pin assembly is the programming port, called ICSP (In Circuit Serial Programming). It is compatible with many programmers, including the PICKIT 2 and PICKIT 3 from Microchip.

M-PWR-1.jpg
 
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Update to the Update. Here's a photo of the stick mount for the vibration motor. I'm still tweaking the motor control algorithm... right now it's better to consider this to be a haptic feedback mechanism than a true stick shaker. The enhancements are to provide an increasing amplitude and pulse frequency, not just amplitude control. I haven't tried it under the seat cushion yet.


shaker.jpg
 
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After my earlier... snarky reply, I gotta say... this is looking better. At a minimum... from the electronics side. Maybe when I get a demo flight someday I will understand better. I always like to be "better educated". Particularly at altitude. Nice work so far.
 
flightlogic said:
If you can't see your lift reserve indicator... MOVE it.
Click to expand...
Yeah. But as an engineer I like data, and didn't the aforementioned Kitplane article note that some quantitative field studies were done, and pilots with stick shakers reacted measurably faster than to aural or visual warnings? Pretty sure that's true. Pretty sure that in some cases, a faster reaction at low AGL could save life, limb and aircraft.

Besides, that's why these are Experimental. If I had the electronic chops I might try it myself.
 
A brief history of my Stick Shaker

In about 2004, Dynon introduced its D10/D10A products. One of the features was the serial data link that presented digital air data, including airspeed and angle-of-attack.

In 2006, I developed a device that sniffed this data stream, called the V-Speed ADS. It presented either AoA or V-speed information using a sequential color-coded LED display. It mounted on the glare-shield in a horizontal or vertical position to provide a line-of-sight display for this critical information.

ADS-vertical.jpg


V-Speed ADS (circa 2006)

In 2011, I wrote the 'FIX' protocol (Flight Information eXchange) that brokered both Dynon and Garmin to use the same or similar serial data streams in the SkyView and G3X EFIS systems. These data streams provided air data, engine data and system data to external devices. This FIX protocol was largely adopted by the respective vendors.

At about the same time, I decided to provide my full catalog of avionics designs as 'open source' hardware. The concept here was that I was never going to get rich manufacturing and selling these devices into a relatively small market, but I want the intellectual property to live on.

MakerPlane then stepped in as a partner in the open source movement and began offering my products kitsets and finished devices to those folks unwilling or unable to build their own from the ground up. I then focused on development of new products that I could then 'give away' as open source designs to the community.

So the stick shaker represents the latest in line of these open-source designs and the culmination of my 8 years of AoA indicating device development . This year so far, I have released a 2-axis electronic trim controller with speed scheduling and automatic fault correction; a magneto tach pulse stabilizer for EFIS systems and the stick shaker is next.

M_PWR_2_complete__47407.1397408917.1280.1280.JPG

M-PWR-2 Trim Controller (2014)

I have been in active development of this stick shaker for over a year off and on. It's now working and flight tested and the production pcbs are in-house today. You will notice that my designs are primarily through-hole which makes them very easy for the average electronic hobbyist to assemble. This is a continuing theme, but it probably won't last forever as surface mount takes over.

I am about to take a BOD position in an aerospace electronics company so my design productivity is likely to suffer as I worry about bigger issues.

Finally, I challenge all of the other folks at VAF who do similar types of electronic (or mechanical) designs to join the open source movement and give away as much knowledge as possible to advance our avocation.

Cheers,
 
OK, I'll bite

Vern,

I will be the first to bite. How can I order one of these? Have SkyView and the know how to install.

Can you please email me at [email protected]. Yes, I have one too.

Thanks.

Brian
 
vlittle said:
In 2006, I developed a device that sniffed this data stream, called the V-Speed ADS. It presented either AoA or V-speed information using a sequential color-coded LED display. It mounted on the glare-shield in a horizontal or vertical position to provide a line-of-sight display for this critical information.

ADS-vertical.jpg


V-Speed ADS (circa 2006)
Click to expand...

Any chance that this will be available again? I'd really like to have one of these eventually. (Of course, I'm years away from avionics right now, but still...)
 
F1R said:
Vern,
There is little doubt.
If you build it, they will come and buy it.

If the FAA took a liking to it for GA, you could end up with fuel in the rocket forever.

(Humm Humm---- Humm Humm, I wonder if that vibration is my wife calling, or the AOA increasing):)
Click to expand...

Yikes, you must be a prophet! Showing, once again that no good deed goes unpunished, I have been contacted by a representative of the ASTM committee looking at AoA for spin avoidance for part 23 aircraft. I some how have committed to demonstrating at a forthcoming workshop in New Orleans.

Since I have both the actual stick shaker product and an advanced control-loading haptic simulator flight yoke product through a different company, somehow I've become an 'expert'.

We're all in trouble now!
 
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