"Great way to spend a morning. I quit my full time job at IBM last year to do this (Team Aerodynamix) full time ... and I realized I should have done it a lot sooner." Source: Mike "Kahuna" Stewart, Flight Leader and Founder of Team Aerodynamix.
A barometric scale window of a sensitive altimeter used to adjust the altitude for the altimeter setting. The altimeter uses static pressure as its source of operation.
Even in the Light Sport and Experimental communities, AHRS is becoming more and more common. But the concept for an Attitude and Heading Reference System has been around for over two decades.