On Monday, April 18, 2016 at 5:32:22 PM UTC+12, wrote:
On Sunday, April 17, 2016 at 7:09:28 PM UTC-7, Soartech wrote:
A single probe can provide AoA, airspeed, static, and total energy, it just needs more holes and tubing. Better yet, discard the tubing, put all of the electronics and sensors in the probe, send the data to the cockpit via Bluetooth.

While it's true this can be done these days it will require thousands of man-hours of expensive engineering time. You will end up with something like the Garmin AOA system which is like $1400. My idea was to use a very small vane that has negligable drag and low cost electronics with a much lower price to the pilot so that more people will actually own it. This entire discussion has been very helpful to me and am now considering adding the audio tone option for use on landing approach.

Vanes have their own downsides, in particular being rather fragile. If I was working for Garmin, yes, it would take thousands of man-hours of expensive engineering, but I'm not working for Garmin.

For a 2 hole probe with audio output, I'm not seeing where one needs much more than a couple of high resolution absolute or (preferably) differential i2c pressure sensors, a simple audio amplifier, and a cheap microcontroller with DAC. Easy breadboard project, minimal coding, but I can't design a PCB. Only for experimental gliders, of course...

PCBs are easy. I can put you onto a friend who designs PCBs at home in Dunedin, gets them made in China cheap. He even has a small pick-and-place machine at home for production runs up to a few hundred or low thousands of units.

The hard part is the software to filter and calibrate and interpret the signals. It'd take a few hours of flying, recording the signals, and comparing to a known accurate AOA measurement method (e.g. a decent sized vane on a stick out in the freestream)

I did a similar thing with using an Arduino and exposed thermistor to get a precise (0.01 C relative) and stable temperature measurement for my home heating control. On stormy winter nights with a few draughts around it was amazing how noisy the thermistor output was! No, you don't need to control the temperature to 0.01 C ... 0.1 or 0.2 is fine ... but more accurate measurement lets you pick up any trend early. And in fact I found I was able to usually keep the temperature (as measured by the controller anyway) usually within 0.02 just by switching an oil filled electric heater on or off at 30 second intervals. Worst case errors from starting or stopping cooking, boiling the kettle etc were 0.2 to 0.3, corrected in about 20 minutes -- those heaters have a LONG thermal constant.