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Remote AOA display for any EFIS streaming AOA data

The magic of how the AOA relates to the variable coming out of the EFIS is done by Dynon. Dynon outputs the variable for AOA across a span of 00 to 99.

They code their indicator as follows:

Top of Green = 00
Bottom of Green/Top of Yellow = 50
Bottom of Yellow/Top of Red = 75
Bottom of Red = 99

00 = minimum AOA
50 = some say best glide/best climb angle, I am not sure about that.
75 = critical AOA/Stall point. This is also where the Dynon Audible alarm goes solid tone.
99 = max AOA

I calibrated my Dynon AOA per the Dynon directions and it always stalls around the top of the Red. This is also where the tone goes solid.

Currently my remote AOA indicator matches the Dynon exactly although I might tweak mine. I can also update my parameters from a laptop to make the LED's come on and off wherever I want them to within the 00-99 range. Since I know mine stalls around the variable 75 there is no reason to waste LED's on the 75 to 99 range since extended operation there is not possible.
 
rvmills said:
Well I think I updated the cruise settings on my V-Speed ADS today. Used CoolTerm (thanks Brian), and I fumbled through till I sent the string. I'm pretty clueless on terminal emulators! I saw the unit flash, so hopefully all is well. Will test it next week...once I get my fairings re-done (almost there!).

Paul, I used the same R-Shack USB to serial cable I used to update the Dynon.

Vern, I'll let you know how it worked, or make that "help" call after I fly it again.

On the low speed AOA range, how are the default AOA percentages selected...are they set to match the color changes in the Dynon, or do those percentages represent something specific aerodynamically? I know they are percentage of stall AOA, but is there a science to what percentages are selected (this or that happens at that percentage)? Do they also also correlate to speed increments over stall (like 1.3 Vso for a ref speed...would that be 77% or 1/1.3)? Is it linear like that? Just wondering, in case I want to play around with the low-end a bit. Thanks!

And Brian, just to keep from totally stealing your thread, how does your program light the LEDs...is it an electronic power on/off repeater that matches the Dynon AOA lines' on/off status (if that is possible), or does it measure the AOA percentage like Vern's. More wunderin'! :)

Cheers,
Bob
Click to expand...

Hi Bob.
The factory defaults are shown on page 6 of the documentation. They are virtually identical to the Dynon ranges, subject to the resolution of 8 lamps. They were determined by empirical tests before Dynon published their numbers, but line up almost perfectly. They have been flight tested extensively.

Also, the top two yellow and both red lamps will flash, indicating higher AoA, corresponding to the onset of tones from the EFIS.

There is a lot more variation cause by individual in-flight calibration, and some folks like to calibrate differently than Dynon's method. For example, calibrating for maximum AoA in the landing configuration rather than in the take-off configuration (landing with full flaps, minimum power whereas take-off with partial flaps and full power).

I have personally done full-power, full-flap stalls. Quite dramatic, and a tail slide is quite possible.

Of course, you are free to change the setpoints to whatever you wish.

Thanks, V
 
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vlittle said:
Hi Bob.
The factory defaults are shown on page 6 of the documentation. They are virtually identical to the Dynon ranges, subject to the resolution of 8 lamps. They were determined by empirical tests before Dynon published their numbers, but line up almost perfectly. They have been flight tested extensively.

Also, the top two yellow and both red lamps will flash, indicating higher AoA, corresponding to the onset of tones from the EFIS.

There is a lot more variation cause by individual in-flight calibration, and some folks like to calibrate differently than Dynon's method. For example, calibrating for maximum AoA in the landing configuration rather than in the take-off configuration (landing with full flaps, minimum power whereas take-off with partial flaps and full power).

I have personally done full-power, full-flap stalls. Quite dramatic, and a tail slide is quite possible.

Of course, you are free to change the setpoints to whatever you wish.

Thanks, V
Click to expand...

Vern,

I did the calibration per the Dynon manual, and see the performance and flashing you describe on the ADS...works well. And concur with you, power-on, dirty stalls are quite an eye-opener!

As for changing the set points, not sure I will, but before I do that, I want to make sure I know what I'm doing, and what I'm changing it to. More discussion below Brian's quotes...

Brantel said:
The magic of how the AOA relates to the variable coming out of the EFIS is done by Dynon. Dynon outputs the variable for AOA across a span of 00 to 99.

00 = minimum AOA
50 = some say best glide/best climb angle, I am not sure about that.
75 = critical AOA/Stall point. This is also where the Dynon Audible alarm goes solid tone.
99 = max AOA

Since I know mine stalls around the variable 75 there is no reason to waste LED's on the 75 to 99 range since extended operation there is not possible.
Click to expand...

Brantel said:
aoa_cropped.jpg


The variable's range is 0-99.
0 maps to the bottom of the Green
49 is top of the Green
50 is bottom of the Yellow
74 is top of the Yellow
75 is bottom of the Red
99 is top of the Red
Click to expand...

Brian (and Vern),

This is the kinda thing I was also looking for, so I can over-anal-yze this some more. :rolleyes: (not really, just having fun between fairing sanding sessions).

Back in my squid days, we had an AOA guage and an indexer. 15 units was on-speed for an approach, and that was the needle at 9 o'clock on the gauge, and the yellow donut on the indexer. Cruise was 4-5 units, IIRC. I guess I'm trying to determine where the "donut" is on the ADS.

The high speed mode of the ADS is straight forward, its set for various speeds. The low speed mode can also be set for speeds, but I'd like to maintain its AOA function and use that. What I'm trying to determine is what those AOA percentages, and thus the lights, are telling me, in terms of best glide, min sink, and stall.

I did this chart to compare your values from above to Vern's default chart:
AOA.jpg


Looks like the data stream numbers Dynon gave you correlate closely to Vern's percentage of AOA, and apparently those percentages are not a percentage of critical (stall AOA). Before I go changing the set points, I'd want to know how to calculate an AOA % for min sink, best glide, 1.3 Vso, etc.

Perhaps the easiest way to use it would be to just go out and fly multiple landings at various speeds, and note where the lights are...then fly that as needed (airpeed failure or just as a cross-reference). I've had the ADS for a while, but have just not gone through the rigor of closely calibrating it to various approach speeds.

Quick side note, you mention above that 50 = Best Glide / Vx. Isn't Best Glide closer to Vy, while Min Sink is closer to Vx? I know they aren't spot on, but I thought this was a rule of thumb. That's why I put my notes out to the right above.

Off to go get dusty (sand-fill, sand-fill), but thanks for the discussion!

Cheers,
Bob
 
Bob,

As stated above, not sure that what I have seen is correct on that subject. I really do not think it is. I would say you are correct. It will take testing to determine those relationships...
 
Brantel said:
Bob,

As stated above, not sure that what I have seen is correct on that subject. I really do not think it is. I would say you are correct. It will take testing to determine those relationships...
Click to expand...

But a good use of Avgas, eh! Have AOA, will play! :D

Once I'm back up and flying (next week hopefully) will commit some time to this, and report back. Will be interesting to compare notes!

Cheers,
Bob
 
Brantel said:
If anyone wants details on how to build one, let me know!
Click to expand...

Brian:

Awesome work! This looks like a fun DIY project and I'm a big fan of the Arduino/Freeduino platform. Any chance you could post the Arduino sketch you used with your Bare Bones Board? I'm especially interested in the serial comm setup and how you interpret data from the Dynon.

Thanks!
 
aeropunk said:
Brian:

Awesome work! This looks like a fun DIY project and I'm a big fan of the Arduino/Freeduino platform. Any chance you could post the Arduino sketch you used with your Bare Bones Board? I'm especially interested in the serial comm setup and how you interpret data from the Dynon.

Thanks!
Click to expand...

Here you go as promised...this is not the final version but it is close enough. I optimized it a little from here and added a few custom features that I wanted. If you have any questions, let me know...

Code: 
#include <Messenger.h> //Loads the Messenger Library
Messenger message = Messenger(44); //Sets the delimiter to a "," but it is not needed in this case because there is no delimiter in the data
#define MAXSIZE 60 //Definces the message buffer array size
char string[MAXSIZE]; //Defines string, creates the message buffer array
char AOAData[3]; //Create array for AOA data
const int AOABase=10; //Set the base for the strol function to HEX			
int AOA = 0; //Define the AOA Variable
const int ledPins[] = {
  4, 5, 6, 7,8,9,10,11,12,13,14,15,16}; // an array of pin numbers to which LEDs are attached
int ledState = LOW;             // ledState used to set the LED
long previousMillis = 0;        // will store last time LED was updated
// the follow variables is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long interval = 30;           // interval at which to blink (milliseconds)

void setup() 
{
  Serial.begin(115200); //Initialize the hardware serial port
  // loop over the pin array and set them all to output:
  for (int thisLed = 0; thisLed < 13; thisLed++) 
  {
    pinMode(ledPins[thisLed], OUTPUT);
  }
  message.attach(messageCompleted);
}

void loop() 
{
  while ( Serial.available() ) message.process( Serial.read() );//This routine is what loads the ASCII stream packets into the messenger
  int AMBI = analogRead(5);
  int DIM = map(AMBI, 1023, 0, 255, 2 );
  analogWrite (3, DIM);

  if (AOA >= 62) 
  {
    unsigned long currentMillis = millis();
    if(currentMillis - previousMillis > interval) {
      // save the last time you blinked the LED 
      previousMillis = currentMillis;   
      if (ledState == LOW)
        ledState = HIGH;
      else
        ledState = LOW;
      //Serial.println(ledState);
    }
  }
  else ledState = HIGH;

  //Control the Green LED's
  if (AOA < 9 ) digitalWrite(16, HIGH);
  else digitalWrite(16, LOW);
  if (AOA < 17 ) digitalWrite(15, HIGH);
  else digitalWrite(15, LOW);
  if (AOA < 25 ) digitalWrite(14, HIGH);
  else digitalWrite(14, LOW);
  if (AOA < 33 ) digitalWrite(13, HIGH);
  else digitalWrite(13, LOW);
  if (AOA < 41 ) digitalWrite(12, HIGH);
  else digitalWrite(12, LOW);
  if (AOA <= 49 ) digitalWrite(11, HIGH);
  else digitalWrite(11, LOW);

  //Control the Yellow LED's
  if (AOA < 55 ) digitalWrite(10, HIGH);
  else digitalWrite(10, LOW);
  if (AOA < 62 ) digitalWrite(9, HIGH);
  else digitalWrite(9, LOW);
  if (AOA < 68 ) digitalWrite(8, ledState);
  else digitalWrite(8, LOW);
  if (AOA <= 74 ) digitalWrite(7, ledState);
  else digitalWrite(7, LOW);

  //Control the Red LED's
  if (AOA < 82 ) digitalWrite(6, ledState);
  else digitalWrite(6, LOW);
  if (AOA < 90 ) digitalWrite(5, ledState);
  else digitalWrite(5, LOW);
  if (AOA <= 99 ) digitalWrite(4, ledState);
  else digitalWrite(4, LOW);

}

void messageCompleted() 
{
  while ( message.available() > 0) 
  {
    message.copyString(string,MAXSIZE); //Copies the Messenger Library packet into the string array

    //AOA DISPLAY    
    AOAData[0] = string[39]; //Load the first ASCII representation of the first HEX number into the array
    AOAData[1] = string[40]; //Load the second ASCII representation of the second HEX number into the array
    AOAData[2] = '\0'; //Load a Null character into the array
    AOA = strtol(AOAData, NULL, AOABase); //Run the strol function on the AOAData array and return the variable to AOA
    //Serial.println(AOA, DEC); //Used for monitoring, comment out for normal mode
  }
}
 
Brian:

Thanks a million -- this helps a lot! I've never used the Messenger library before, can't wait to get started. SparkFun here we come!

BW
 
I used Modern Device for my gear. They have a really small RBBB board kit that fits nice in these small boxes.

The library works great. It keeps up with the high data rate of the Dynon without dropping a single bit....
 
Vx Aviation V-Speed ADS remote AoA indicator is back!

This has to be the ultimate thread hijack, sorry Brantel!

Due to popular demand, much arm twisting and feelings of guilt, our remote AoA indicator is back in production. The V-Speed ADS has more than 5 years flight experience in numerous aircraft, and is supported by both Dynon and GRT Avionics. MGL is also considering support.

The V-Speed ADS is a glareshield mounted remote AoA indicator that interprets a serial air data stream to present a progressive bar graph type display in a 'heads-up' type location.

It also presents cruise flight information at low AoA's, such as (programmable) Vfe, Va, Vno and Vne. If you don't have an AoA probe, it can be programmed for a slow flight display of Vx, Vref, Vso and Vs1

It has an internal light sensor that automatically dims for night operation.

The device comes with a 5' tefzel shielded cable, SPDT switch (for in-cockpit programming access) and velcro for mounting. The datasheet can be downloaded from the vx-aviation.com website.

Availability: Devices are in stock.
Price: See website for ordering $250 including shipping anywhere in the world.

Thanks to the many (!) VAF members who have shown support.

Thanks,
Vern
 
Last edited:
Well, since Brian said no problem on the Hijack.....

I flew with Vern's little indicator last night for the first time hooked up to the GRT system in the Val, and it works exactly as advertised! I have had the GRT AOA on the EFIS ever since they wrote the software, and have good confidence in the algorithm's and how it works for approaches - but it is really not very useful on the panel - I just don't look there when I am on final approach.

Having the data on the glare shield makes it much more useful, and I found Vern's very easy to install - took about 30 minutes to pull an HX, splice into the power and ground, and make a pin for the single serial line. For test purposes, i just ran the cable out the bottom of the panel and velcroed it in place and went flying. It was a very bright day, and I found the LED's a bit had to see with the sun coming from right behind me (remember, this is an -8 with a full bubble), but it showed me just what I wanted to see on approach.

I have to do a little tidying up, route the cable permanently through the glare shield, and pick a good location, but I think I'll be keeping it for now. I have spent way to many years flying light airplanes to retrain myself to fly AOA on every approach, but for short fields when you want to operate right on the edge, or to make sure you stay safe in a complex environment (such as Oshkosh) with a load (such as carrying gear to Oshkosh), it could be a lifesaver.

I'm glad that Vern is going to produce this again - I had told GRT several times that it would be a nice thing to have, as it would make their AOA algorithm actually useful to folks without them having to pay for a dedicated AOA system. Add AOA for $250? Can't find a much better deal than that - and no additional plumbing!

Thanks again to Brian for kick-starting this topic!

Paul
 
Thanks for the Pirep, Paul.

Here's an image of some of the first units from the new production batch. There's a naked one in there (blush) as well. You can see that the hardware appears to be simple. Turns out the machining on the enclosure is the most complex operation. Go figure.

Not shown is the firmware. It's 1011001100100011010.... oh, forget it. About 3 person-months of development, and 5 years of flight testing.

V-speed-multi.jpg


Thanks, V
 
Vern
I just ordered one.
I, possibly like some others, won't be using it for a few years and can't test it till then.
I am mindful of caution with early batches of anything and your understandable decision in past to stop production. Hopefullly demand now will allow long term production to be available.
So, not meaning to be offensive, how do you test them before dispatch, and is there a warranty period? How long will you offer support for them? Are you planning to stay in production or just make a batch and stop?
The answers to these impertinant questions won't change my order - I want one and don't want to find out in a couple of years that they are no longer available.
John
 
rjtjrt said:
Vern
I just ordered one.
I, possibly like some others, won't be using it for a few years and can't test it till then.
I am mindful of caution with early batches of anything and your understandable decision in past to stop production. Hopefullly demand now will allow long term production to be available.
So, not meaning to be offensive, how do you test them before dispatch, and is there a warranty period? How long will you offer support for them? Are you planning to stay in production or just make a batch and stop?
The answers to these impertinant questions won't change my order - I want one and don't want to find out in a couple of years that they are no longer available.
John
Click to expand...

Hi John, just received your order.
To answer your questions:
Not an early batch, it's the identical design and production steps for the last five years.
Every unit is 100% tested against the datasheet with an in-house test suite that allows complete configuration and testing.
Yes, there is a warranty period. If it ever malfunctions due to a manufacturing defect, we will replace it, within reason. If you break it, minimum shop charges will apply to have it repaired (currently $75).

We've even replaced a product that the customer sent back as defective after 3 years of storage: It was so badly corroded that the pcb traces were completely gone and the connectors were pitted with rust. Cost him $75.00 for a brand new device. Lesson learned: don't store electronics in a wooden box in the rain or with corrosive chemicals around.

Now that we're back in production, we plan to continue the product for as long as there is a demand for it. Now that GRT and potentially MGL are supporting it as well as Dynon, it looks like it will have staying power. We've also had some discussions with Garmin, but it's a bit early to make any claims on that.

Thanks, V
 
Thanks Vern
Any suggestions on how to store it? Like keep it dry. Probably just common sense.
John
 
Last edited:
rjtjrt said:
Thanks Vern
Any suggestions on how to store it? Like keep it dry. Probably just common sense.
John
Click to expand...

Just like any electronic device. Just keep it dry and in a controlled environment, like a desk drawer. Now that you mention it, I always have a dehumidifier running in my cockpit when I'm not using my a/c (I live on the coast). Temperature changes can lead to condensation and corrosion of some susceptible components (like switches). This affects electronics as well as airframes and engines.

There are no connectors of any type that can corrode, or electrolytics that can dry out so it should be very reliable. I'll bet you a latte that 25 years from now it will still be working.

V
 
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Rainier Lamers said:
It's one of those "Dang !" things if you know what I mean.

We used to have a serial data steam but took that away due to use of the USB. We are putting a serial stream back but it's quite different as it is actually intended to go into a "black box" flight recorder. As you can imagine, it has a bit more data compared to the Dynon message and due to the nature of the beast the data has to be transferred in a bullet proof kind of way (i.e. the black box recorder only records data that can be strictly verified so it can stand up to scrutiny).

I'd have to make a completely separate arrangement for the Dynon data stream. Don't like that. Let me sleep over it...

Rainier
CEO MGL Avionics
Click to expand...

Rainier, please check out this thread: http://www.vansairforce.com/community/showthread.php?t=70570

We have an initiative on air data protocols. So far, both Dynon and Garmin are working with me on next-gen protocol definition and I'd really like your support and participation.

The Dynon next-gen SkyView protocols are documented there, for example and may be of interest to you. Garmin's should come soon.

Thanks,
Vern
 
I purchased one of Vern's AOA indicators and am wiring it in now. I took the case apart, trimmed it and installed it behind the paned with the LEDs protruding slightly thru holes.
This is a really nifty device and I hate to see it forgotten. :mad:
 
southtarnation said:
Where can I see one (picture) and how much are they? Is there a website?
Click to expand...

This device still exists in the deep dark recesses of the internet. The big plan was to modify it to accept SkyView datastreams as well (that's why I designed the FIX protocol that Garmin and Dynon adopted for the most part).

Well, the volume of this device hasn't justified the investment, so it's kind of languishing. I may have one or two left, but I'm not actively selling it. I've licensed most of my products to MakerPlane (www.makerplane.org), but this was not one of them because of the high cost of support.

If I had to charge for support, this would be a $500 device! Unfortunately, I only sold it for $250.
 
I have one of Vern's indicators that I used with my GRT system - and it worked just as advertised! I have,however, removed it because, well, I like to test different systems - so right now, it is orphaned and sitting on the workbench, so if anyone would like one, and if Vern doesn't have one in stock, I could sell mine. It is in like-new condition - I only temp-installed it during the time I was playing with it.

PM me if interested.

Paul
 
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