I've started to ponder adding an event marker that I could use to indicate areas of interest in the flight test data. I'm using a four-port USB to serial adapter to get the data into my laptop, and I'm only using three of the ports. So, I could possibly wire up the trigger on my stick grip to the fourth port. I would momentarily depress the trigger if there was an event I wanted to mark, and the time would be recorded on the laptop so I would know where to look in the data.

The problem is that at the moment I don't have a clear idea how this could work. Looking at summaries of the RS-232 spec, there are several lines that could legitimately be grounded for long periods, so I would expect that I won't damage the USB to serial adapter if I short them to ground with the stick-grip trigger. I'll probably do a quick experiment sometime this week to see if the Perl Device::SerialPort module that I have been using will cooperate to monitor a port that isn't actually sending a stream of serial data. There seem to be functions to watch for Data Set Ready or Clear to Send, so I might be able to use those.