Many pilots know the Belite aircraft company for their fun experimental aircraft like the Chipper high-performance STOL airplane. They also offer affordable flight instruments through their Radiant Technologies division for experimental airplanes. Their latest development expands their flight instrument offerings to the mobile app segment, with the Precision Altimeter app for iPhone.
The app takes advantage of the pressure altitude sensor in iPhone 6 or newer to display a detailed altimeter instrument and vertical speed indicator. You can also add an external wireless Bluetooth sensor from Texas Instruments for $29 that sends outside air temp and humidity right to the app to display a real-time view of the density altitude. Here’s a quick video showing what it looks like in flight in a Chipper:
The Precision Altimeter app is available in the app store for $19.95.