The FrSky Normal Precision Variometer measures the rate of change of altitude by detecting the change in air pressure (static pressure) as altitude changes. Able to report altitude.
When used with a FrSky transmitter like the Taranis, you can actually create mixes that use the feedback from the vario sensor. For example, you can have your motor reduce power when you reach a set altitude. An excellent feature for sites that have flight ceilings.
Another nice feature of the vario is the ability to connect the FSH-01 sensor hub, thus allowing the X8R receiver's to use the existing analog sensors.
I have a couple of these that I use with D8R-II Plus receivers and they are awesome. I programmed a switch on my Taranis Plus to report my altitude every 30 seconds plus, I added an alarm to automatically alert me when I'm approaching 400 feet.
Both the vario and Aloft are highly recommended!
I have at times flown my planes at club fields with 400ft altitude limits. Trouble was in whose judgement and based on what. With this sensor and a logic switch that is set above 351 ft AGL, and a special function that reports altitude every 5 seconds once the logic switch is set, I no longer have to worry about someones judgement. Great little sensor. FrSky and Aloft rock!
First I must say that my first order arrived in Florida just three days after I ordered it; and by regular postage. Wow!
The vario sensor appears to work great with my D8RII plus receiver, but I've not put it in the air yet. It does however register quite accurately the height from the ground outside to the ceiling inside my home as 13 feet which is quite a bit better resolution than I was expecting. Documentation is a little sketchy, but pouring through the internet gleaned enough information to more fully understand this sensor. It seems to me that almost all the FrSky telemetry stuff is somewhat of an enigma. Everything about this brand seems to work really well at a really good price, so if you are willing to accept a learning curve you can enjoy the fruits of being a pioneer. I still have a lot to learn about the smart port, but I at least already have a place to hook on some more sensory devices.