Brantel
Well Known Member
I am thinking of working on an Arduino based AOA solution as a side project.
My plan is to make a low cost AOA computer out of an Arduino and a small list of components.
Why? Well my plan to upgrade my panel includes a G3X based design and they do not currently support AOA. I have grown to love having a remote AOA display being driven by my current Dynon EFIS. Details on that project here. Also the off the shelf models are too dang expensive and I like to build projects and tinker so here we go....
This new AOA computer/display will be based on and very similar to the prior project only it will do it's own AOA calculating instead of relying on an EFIS to do it.
So far the rough BOM has these major components:
1ea Arduino UNO (This is what I have on hand. One of the smaller cheaper ones most likely will work after the prototype is developed.)
2ea Differential Pressure Sensors (I have ordered two ranges to experiment on what gives the best resolution. +-3psi and +-1psi 0Vmin/2.5v@0DP/5Vmax. This is what is readily available off the shelf)
1ea Dynon AOA pitot (I will tap into the Pitot/Static/AOA lines existing in my A/C)
1ea Array of LED's of choice
1ea Ambient Light Sensor for auto dimming
1ea small switching transistor for PWM dimming the LED array
1ea small project box
Design intent:
It is pretty simple. Take the two DP sensors, tie one pneumatic port of each of them together with some tubing/T and connect that to the static line of my A/C. Take the other port of sensor1 (AOA Pressure) and connect it to the AOA line off of my Dynon AOA Pitot. Take the other port of sensor2 (Pitot Pressure) to the pitot line off of my Dynon AOA Pitot.
Bring those variables into the Arduino via the analog ports.
Scale to the AD converter output to something human readable.
Divide the "AOA Pressure" variable by the "Pitot Pressure" variable and create a "Raw AOA" variable.
Develop some sort of calibration routine that scales the "Raw AOA" variable across 4 calibration points.
1. Zero lift
2. Best performance ~ 1.5 x stall
3. Best approach ~ 1.4 x stall
4. High angle warning ~ 1.15 x stall
Since the Raw AOA variable should be fairly linear, there is no need to go all the way to a stall, it can be calculated.
There will be two calibrations to account for flaps and no flaps. I plan to use the Arduino serial port to monitor the G3X's datastream for the flap position in order to not require an additional flap deployed switch.
Thinking of another glare shield mounted LED array display similar to the one I did before.
Planning the following LED configuration:
I will also provide a tone generator output that will provide progressive tones as one approaches #4 above.
There will be an ambient light sensor that will enable automatic dimming of the LED array using the PWM output of the Arduino to control a small switching transistor sinking the LED array current. I did this on my prior project and it works great.
This should be able to be built for less than $100 not counting the Dynon AOA Pitot. Several examples of how to build your own AOA probe are in the archives of this forum.
Anyone got any additional ideas or suggestions?
FYI, this project will be open source, not for profit, not commercially produced and for personal use/education only.
My plan is to make a low cost AOA computer out of an Arduino and a small list of components.
Why? Well my plan to upgrade my panel includes a G3X based design and they do not currently support AOA. I have grown to love having a remote AOA display being driven by my current Dynon EFIS. Details on that project here. Also the off the shelf models are too dang expensive and I like to build projects and tinker so here we go....
This new AOA computer/display will be based on and very similar to the prior project only it will do it's own AOA calculating instead of relying on an EFIS to do it.
So far the rough BOM has these major components:
1ea Arduino UNO (This is what I have on hand. One of the smaller cheaper ones most likely will work after the prototype is developed.)
2ea Differential Pressure Sensors (I have ordered two ranges to experiment on what gives the best resolution. +-3psi and +-1psi 0Vmin/2.5v@0DP/5Vmax. This is what is readily available off the shelf)
1ea Dynon AOA pitot (I will tap into the Pitot/Static/AOA lines existing in my A/C)
1ea Array of LED's of choice
1ea Ambient Light Sensor for auto dimming
1ea small switching transistor for PWM dimming the LED array
1ea small project box
Design intent:
It is pretty simple. Take the two DP sensors, tie one pneumatic port of each of them together with some tubing/T and connect that to the static line of my A/C. Take the other port of sensor1 (AOA Pressure) and connect it to the AOA line off of my Dynon AOA Pitot. Take the other port of sensor2 (Pitot Pressure) to the pitot line off of my Dynon AOA Pitot.
Bring those variables into the Arduino via the analog ports.
Scale to the AD converter output to something human readable.
Divide the "AOA Pressure" variable by the "Pitot Pressure" variable and create a "Raw AOA" variable.
Develop some sort of calibration routine that scales the "Raw AOA" variable across 4 calibration points.
1. Zero lift
2. Best performance ~ 1.5 x stall
3. Best approach ~ 1.4 x stall
4. High angle warning ~ 1.15 x stall
Since the Raw AOA variable should be fairly linear, there is no need to go all the way to a stall, it can be calculated.
There will be two calibrations to account for flaps and no flaps. I plan to use the Arduino serial port to monitor the G3X's datastream for the flap position in order to not require an additional flap deployed switch.
Thinking of another glare shield mounted LED array display similar to the one I did before.
Planning the following LED configuration:
I will also provide a tone generator output that will provide progressive tones as one approaches #4 above.
There will be an ambient light sensor that will enable automatic dimming of the LED array using the PWM output of the Arduino to control a small switching transistor sinking the LED array current. I did this on my prior project and it works great.
This should be able to be built for less than $100 not counting the Dynon AOA Pitot. Several examples of how to build your own AOA probe are in the archives of this forum.
Anyone got any additional ideas or suggestions?
FYI, this project will be open source, not for profit, not commercially produced and for personal use/education only.
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