On Monday, April 18, 2016 at 1:16:33 PM UTC-7, wrote:
On Monday, April 18, 2016 at 2:48:16 AM UTC-7, Bruce Hoult wrote:
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.
I do embedded software and know enough about digital logic design to get into trouble, but design of a proper PCB (or analog circuitry) is beyond me.. It is getting quite easy to cobble together sophisticated devices on a breadboard.
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'm not so sure one needs an accurate absolute numeric AoA, so much as a repeatable measure of how close you are to stall AoA. Such a system would need to be calibrated for each glider installation by going up and stalling in various configurations. I have some practical experience on the filtering side, including working with another poster is this group to build a flight computer with digitally differentiated variometer about a decade ago (when there was more of a need for analog circuitry). We did hours of flying (and driving fast up/down steep hills), before we managed to get the filtering right.
It is amazing the amount of processing power that's available. Here's a board with a magnetometer, 3-axis accelerometer and precision pressure sensor for under $16. The pressure sensor is calibrated for a limited range of atmospheric presssures (ground level to 500 mbar), but this is still pretty cool.
https://www.element14.com/community/...c-sensor-board