I've been working on the Ardustation 2 software since August 2011 and I've finally gotten around to adding a feature that has been asked for more than once: a buzzer warning when the received Mavlink aircraft battery voltage has dropped at or below a set value. The buzzer is sounded ( at LCD screen updates - 1 Hz) when the voltage is at or below the set warning value while the "flight data" screen is displayed (see below).
Switching to another screen will silence the buzzer until the flight data screen is brought back up. I wanted a way to silence the buzzer if necessary and this mechanism turned out to be the simplest way to implement it - given the need for an interrupt driven buzzer timer. All other features of version 2.0.17 are intact (antenna tracking, parameter update).
I had a chance to test fly 2.9.1 on my Arducopter over the Easter weekend and this worked pretty well to keep my 4000 mah 3S Lipos from exceeding the use of 80% of the batteries capacity. Using a HobbyKing 3S voltage warning was killing the life of my batteries. After 12 flights trying to slowly increase the flight times vs battery remaining capacity, I settled at a warning at 10.6 volts (my quad's current drawn is about 20 amps at a hover) and that is the default in the software. I have another 2 minutes of flight time to land after the buzzer continously sounds and I'm happy that I'm not puffing my Lipos anymore. This can be easily changed to other values in the source code before loading into the Ardustation.
My Ardustation has served me well over the last 2 years and I don't anticipate adding any other features since RAM and screen real estate is very tight. Thanks to everyone who has downloaded the software and provided feature requests and comments and to the code contributors who have worked on Ardustation 2.
As always, the software is available at this link. Be sure to test this with your aircraft on the ground to verify that you understand the behavior and its limitation. I've only tested the voltage monitor with my quad - although it should work with airplanes also.
Compile this code only with the library contained within the zip file. The libraries provided with APM or ACM source code have changes that will cause compilation errors. This code can be compiled with Arduino 1.0.1 or 1.0.3.