Avare With Stratux - Overview and Options

[Greg Kelley]

Avare is stupendous (or pick your own super positive descriptor), I/O Module makes it better, and Mike's ADS-B really tops it all off.

However, there are some things to consider. The NooElec Nano-2 receiver is a bit of a power hog (feel how warm it gets). Using it with an OTG cable eliminates the ability to connect power to your tablet in almost all cases. Some folks have torn into a Y cable and experimented with adding resistors to get the tablet to charge and be a USB host at the same time. Some folks have added a powered USB Hub so the receiver doesn't pull power from the tablet. Depending on your tablet model and flight time, you could run out of battery in flight.

One solution is Stratux, a free open source program that runs on a Raspberry Pi and sends the ADS-B data from the receiver to your tablet via Wifi. To get Stratux up and running you need to purchase a Raspberry Pi-2 (or the Stratux recommended Kit) and a KMASHI 10k aH battery pack to power the Pi. Download the Stratux image, transfer to a Class 10 4Gb Micro SD, insert into Pi and off you go. The kit comes with an Edimax USB Wifi which works out of box. If you already own a RasPi you can still run Stratux if you get the Edimax Wifi. I have the last version of the RasPi, the B+ with 700mHz CPU. I got mine as a kit from Canokit and it came with a Canokit USB Wifi which I got working in Stratux with a few minor modifications to some files (using SSH to Login to the Linux style OS on the RasPi). If you're not a 'computer person' (tech-head/geek or don't want to spend a couple hours playing with this), then get the Edimax so you don't have to make any changes. Plug in the Wifi and Nano-2, connect the RasPi to the battery pack, and place it anywhere you can get a good signal with the receiver. Now your tablet has nothing connected and you can plug in a 12v to 5v power plug (using aircraft power if you have a 12v outlet) to keep it running. The tablet uses wifi to talk to the RasPi running Stratux. Having your tablet on or near your panel without any cables or just one power cable keeps things tidy. An organized cockpit is a safer cockpit.

I have just ordered the newer RasPi-2 and the Edimax Wifi. I also ordered a Mini Powered USB Hub for testing various configurations and power usage.

Costs:

Raspberry Pi-2 - $38  (Ebay)
Edimax Wifi - $13 (Ebay)
KMASHI 10k aH Battery - $13 (Ebay)
4Gb Class 10 uSD - $5 (Walmart)
Zebra Case - $14 (Ebay)
Total: $73

Options:

Tripp Lite Ultra Mini Powered HUBU222-004-R $20
NooElec Nano-2 $27 (NooElec on Ebay)
978MHz Stubby Antenna $5 (Ebay)
Right Angle Antenna Connector $3 (Ebay)

I will post updates to this thread with results from testing with the powered Hub, different antennas, etc.

[Greg Kelley]

Tip For Shutting Down RasPi Cleanly:

Shutting down 'cleanly' will help eliminate the chance of corrupting your uSD card. To shutdown the RasPi use an SSH Client (I use Juice SSH on my Android). Login to the RasPi as p...@192.168.10.1 password raspberry and type the command 'sudo shutdown -h now'. This will close all apps, dismount drives, and not only power off the RasPi but with an attached KMASHI power pack, it will shut that off automatically as well. Close your SSH Client and you're done.

Also forgot to mention in OP that if you don't have aircraft 12v power just attach another KMASHI pack to your tablet if it looks like it's running low on battery.

[Fred Worrell]

The newer Stratux software release web page has a restart function and a shutdown function.

[Greg Kelley]

Yeah I was going to go back and add that to my post and say that my SSH routine was for those not running the browser interface but we can't edit our posts. I did try the shutdown in the webUI but it doesn't do a full power down like the command line does.

UPDATE: Just tried both the shutdown and poweroff commands again and now the RasPi doesn't power off like it was doing earlier. Don't know what's up with that. Oh well, back to pressing the power button on the KMASHI.

 

[Greg Kelley]

Raspberry Pi Compatibility:

The latest version of Stratux has been compiled for the ARMV7 which is on the Pi 2. The older Pi B+ uses an ARMV6. I tried the latest Stratux release and it doesn't run on the B+. I even tried to compile from source and it doesn't compile since the code is set for the ARMV7. The creator of Stratux states that ARMV6 is no longer supported and you must run Stratux on a Pi 2 with ARMV7.

There is a new Pi called the Zero. They sell out in 24hrs when Adafruit gets them in, so I'm on the waiting list for the next batch. The Pi Zero uses an older ARMv6 architecture, which is confusingly also called ARM11, so it won't run Stratux either. Pi 2 is your only option for Stratux.

There is also a new sub $10 credit card computer coming out this summer called the C.H.I.P. ($9) and it uses the ARMV7 so should run Stratux. I will get one and test once they're released. It has 4Gb Flash Memory (like the BeagleBoneBlack) and it has onboard WiFi and one USB port for the Nano-2 (no more WiFi dongle needed). Hopefully the Stratux guy will offer a version that supports the C.H.I.P. Wifi and if we're lucky his current version will support it out of the box. Stay tuned...

[cyo...@gmail.com]

Greg, you can get it working on ARMv6 without much trouble. Replace the Go compiler binaries with ARMv6 ones (or recompile the Go compiler). In my Zero tests, I used the Dave Cheney binaries. See the stratux forum where I've outlined the preliminary tests. Stratux ran great on the Zero but has not been tested extensively on this platform since it is so new (and hard to get a hold of).

We're encouraging users now to go with the Pi2 since it gives us more resources to work with. Even though the Pi2 offers far more processor/memory than we currently need, I've been working to reduce the processor/memory/power footprint in preparation for the Zero. Give the latest code a try.


-Chris

[Greg Kelley]

Thanks Chris, just did a stratux build on my B+ using go 1.5.2 everything built fine and stratux is now up and running. Only glitch I see is some traffic is reporting 65535kts - strange. Picking up a single tower in Epsom, NH between MHT, CON, and PSM from the ground although I'm at 1000; MSL.

Using the WiFi dongle that came with the Canokit package I bought - it's a RTL2832U. Had to apt-get install hostapd (newer/different version) to support the nl80211 driver that the Canokit needs.

gen_gdl90 is running between 55 and 65 percent CPU according to top.

I also discovered that wlan0 does not get it's IP assigned if you have eth0 connected. Same thing happens on my Kubuntu desktop. Must disconnect ethernet cable to get WiFi to activate.