Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater

Sun, 24 Sep 2017

Oh, Stratux

Last Christmas, I got a Stratux box as a present. This is a little Raspberry Pi tiny-computer with a couple SDR dongles attached, which will listen to aicraft traffic and show it on a tablet. But if you needed that introduction, you can definitely skip this entry, for it will go Deep Nerd on the Stratux, and be incredibly boring for you.

My particular Stratux was running version 0.8r-something (I forgot to note exactly which version it was). It worked pretty well, but on the last few flights, it started doing this thing where it would stop sending traffic to the tablet. If I pulled the power and rebooted it, it could come back for a period of time, but never for terribly long.

So, I decided I would try loading current software on it. The Stratux project is up to 1.4r2, which is a pretty substantial leap. I downloaded the upgrade script for 1.4r2, and sent it in via the Stratux web page. Once I re-joined the wifi network, all appeared to be working, so I tucked it back into the flight bag, and brought it with me for today's flight.

It all seemed to be working for the first maybe 20 minutes, but as soon as I was done with my pattern work and departed for Jefferson County to see if they had any pie left (gotta have some kind of goal, right?), I noticed I wasn't seeing traffic again.

Sighing a bit, I pulled the power and plugged it back in again, wondering if I had burnt out some part of the hardware. It wouldn't be the end of the world if I had, but how annoying. However, it didn't come back. In fact, the wifi network didn't show up again either. That was weird. Made troubleshooting harder too, since I didn't have any other way to access the Stratux than wifi.

I tried a few more times on the way to and from JeffCo, but didn't have any luck. This was just kind of piling on, since I'd already blown 40 minutes trying to retrieve a pen that mysteriously ended up in the belly fabric under the cockpit (a royal pain to deal with, and had me seriously considering whether I'd have to bring in a mechanic to solve it), and discovered that my inexpensive endoscope camera had mysteriously died between the last time I used it and today, when I really wanted it to be working, so I could locate that stupid pen. (I did ultimately get the pen out, by locating it through primitive tap-based echolocation on the fabric, then tapping it so it ended up in a spot I could reach past the baggage area.)

Anyway, discouraging to have all these things going wrong, seemingly all at once.

I brought the box home, and found some information, which I thought others might enjoy seeing as well.

The first tidbit: the green "status" light (labelled ACT on the Raspberry Pi 3) was blinking rapidly, about 5 times per second. I downloaded the source code, and found where that gets set. Unhelpfully, it does that any time the Stratux software encouters a "critical error." Not terribly specific, but I knew at least that the software was still running, though it had croaked in some fairly fundamental way.

The next tidbit: I found this bug report suggesting that other people are having a similar problem. Specifically, they saw the flashing green light, and the lack of wifi, and they were using the same 1.4r2 version that I was. One mentioned that downgrading to the older 1.2.r2 version worked correctly, so I decided I'd try that.

Since I'd upgraded the system, and it had knocked the wifi offline, the only way I could do anything with it would be to reload the SD card. So I found the Stratux release page, and located the 1.2r2 release image. Next, I had to figure out how the Stratux folks want you to blow an image onto the SD card, so it was off to the Raspberry Pi documentation page to figure it out. They want you to use some new graphical tool, but I'm sufficiently oldschool that I just wanted the dd command line. Fortunately, they have it, couched in a whole lot of "You don't know anything about Linux, so..." exposition, but they have it. I dd'd the image file onto the SD card, and have now had it running for just over 50 minutes, without apparent issues.

So, two out of three things were salvaged today: I got that stupid pen out of the belly (and it will always live in its elastic loop on the kneeboard from now on), and I got the Stratux box back into something approaching serviceable order. The endoscope continues to show a black image though, so that may be the end of that. Fortunately, it's one of the $15 variety, so it's not a huge financial hit to replace it. It was more the frustration of having a tool, needing to use it, and it not working like it should when I needed it.

An hour and 6 minutes in, and we're still showing traffic, so I'll call the Stratux upgrade/downgrade a success.

Posted at 21:18 permanent link category: /aviation


Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater