Arduino driven VOR

[SimSupervisor]

So you have it with somewhere between 22k and 32k for the PWM pin. Interesting. I get nearly 100 values each side, which makes me wonder if I read wrongly my resistor and its 30k instead of 3k ???? I didn't do any current measurments, and the pin13 LED didn't seem to dim. I'll check that out next time I work with the VOR. (I have been working on my airspeed indicator this week-end)

Thanks for the information.

[hyamesto]

Yeah, that´s right.
I have between 20k and 30k.
I use two trimpots, but replace the 20k in the graphic with a 2,2k resistor (the most standard near value, my trimpot is set to max value)
Maybe can be put more resistor, but with this value works full resolution).
Think D'ansorval meter like "a sort of LED", no matter the volts, but yes the current (amper).

However, with a 10k works too, but no full resolution (195 steps), and in my Arduino, the power Led indicator, (not the pin13 LED) changes brightness in sync with the max values of PWM output.
(The power led in my ArduinoMega is near of reset button and in front of communication pin RX2, or digital pin 17, and ever is on when the arduino is powered by usb or external battery)
This is a sign of elevated amper consumption.

Measures: with the multimeter in series connection, measuring 2,5mA at full scale.

With 30K, i can´t not measure current, because it´s too low for my multimeter range of current. Needle movement is smoother like the real life VOR. (full resolution)

If I reduce to 10K, there is a 0,5 mA reading on the multimeter, and the movement of the needle is more sharp, and goes to fast from one extreme to other (loose resolution).

Regards.
Horacio.

[Zlatko]

Zlatko:



PS.: Don´t wait me at the airport, flight delayed without explanation...

Come on buddy , don't give up so easily - hire a Cessna and fly it to here your self .
You've got nothing to do till next elections anyway . And on the way back you'll get that fancy encoder.

[SimSupervisor]

Yeah, that´s right.
I have between 20k and 30k.
I use two trimpots, but replace the 20k in the graphic with a 2,2k resistor (the most standard near value, my trimpot is set to max value)
Maybe can be put more resistor, but with this value works full resolution).
Think D'ansorval meter like "a sort of LED", no matter the volts, but yes the current (amper).

However, with a 10k works too, but no full resolution (195 steps), and in my Arduino, the power Led indicator, (not the pin13 LED) changes brightness in sync with the max values of PWM output.
(The power led in my ArduinoMega is near of reset button and in front of communication pin RX2, or digital pin 17, and ever is on when the arduino is powered by usb or external battery)
This is a sign of elevated amper consumption.

Measures: with the multimeter in series connection, measuring 2,5mA at full scale.

With 30K, i can´t not measure current, because it´s too low for my multimeter range of current. Needle movement is smoother like the real life VOR. (full resolution)

If I reduce to 10K, there is a 0,5 mA reading on the multimeter, and the movement of the needle is more sharp, and goes to fast from one extreme to other (loose resolution).

Regards.
Horacio.

Thanks for pointing this out to me. I'll look into putting a bigger resistor. Last thing I want is to sink too much current from the Arduino and kill it during a flight...

Better be safe than sorry.

[xplanematt]

SimSupervisor: As I recall, I also had to hook 12vDC into the power input pin. You probably won't see any indication of power until you feed a good signal to the unit. Mine also has integral lighting, so that's another connection...but the signal itself is just one output from the soundcard, and ground.

If it only takes 1vDC to get full deflection, that's awesome. Just needs a resistor in-line with one of the leads going to the needle.

Hyamesto and SimSupervisor: If you can measure the resistance of the coil driving the needle, you can use Ohm's law to figure out the required resistor value. It probably won't *exactly* match a standard resistor value, you'll want to go to the next LOWEST resistor value (to ensure you get full-scale needle deflection).

Or you can do what I've been doing.....stick a random resistor between the instrument and a 5vDC source and see what the needle does. Keep going up or down with resistors til you find one that just barely pegs the needle. Then you are ready to hook up to your Arduino. There's no risk of over-current on your Arduino this way. Option #1 is the scientific method, option #2 is the caveman method that you might end up having to do a bit anyway if you can't measure the resistance well enough during option #1.

The code is not mine, and I can no longer seem to get in contact with the author, so I am reluctant to share it online. I might throw the WAV files online that I generated, at some point (they are on my old sim, which I have mothballed at the moment). I don't think you'll have much luck using an Arduino Uno to generate the audio, though a faster board with audio synthesis hardware on it (either built-in, or as an add-on) might do the job. I would just stick to a PC, actually.

[hyamesto]

xplanematt:

You are injecting the sound signal in the indicator, or in the radio unit connected to the instrument?
About the connections, if you see earlier post, you can see a original Bendix/King chart scan: the inductance of the D'ansorval is 100 ohms, with the current and/or voltage required for needle or flag deflection. 150 mV, or 0,15 volts (a 15% of a volt), but the important is the minimal current to move the D'ansorval and it's just 140µa (0,00014 ampers).
I was use the scientific method first, and caveman later to make some tweaks.
This I have already tested and it is working ok. Measure current is insignificant.
To generate signals, i was considering to inject a PWM in the internal resolver (but with 4 PWM needed, out of phase by 90º).
The signal to the internal wheastone bridge or resolve, can be a PWM signal as Bendix /King service manuals indicate.
Some little arduino autonomous board can be used only to generate the signals, and supply many instruments.
Or with a mp3 sound and SD card ready shield, you can use arduino to generate sounds, but without many information about you system, this is only speculation.
And again: as Mahatma Gandhi says: "Satisfaction lies in the effort, not in the attainment"......
Regards and thanks for your advices.

Horacio.

[xplanematt]

The audio signal goes directly to the OBS indicator. If you could further modulate the signal at 108.0 to 117.95mhz, you could feed a nav receiver directly. Everything else that connects to the nav receiver would "just work", assuming you fed in the appropriate primary signals (so far we are just talking about the radial signal...there are other signals for the station's Morse code, DME if equipped, and glideslope signal if it's an ILS). So, with just a single audio line, you'd be running horizontal and vertical nav for OBS indicators and HSIs, Morse code audio, real RMIs, RNAVs, DME indicators, etc. That would be amazingly cool, by the way! I don't have a lot of interest in pursuing it further myself, as the "radios" in my Sabreliner are just control heads that I can interface easily. And the OBS indicators, RMIs, and HSIs do not receive the VOR composite signal directly.

Matt

[brenth]

You guys have done amazing work. Did you ever get the "flags" working with the 2 digital outputs? If so, could you post the sketch? Thanks...
Brent