AHRS incorporation

[stephenmelody]

Hello all,

I know the PAW unit has the barometric pressure sensor as one of the features, but would anyone know if it would be possible to have the following integrated?

https://www.adafruit.com/products/1604

Reason I ask, and feel free to slap me down for going off piste, is that I'm moving to the US in a few months, I have 3 semi built PAW units and am patiently anticipating the new board to use in my UK aircraft, but I'd like to have another version for the states from the components I have remaining.

My current units all pick up ads-b traffic, and I'm hoping weather, but that's less important. What would be great is if the PAW unit could integrate that board, giving me AHRS input into the foreflight app.

I'm guessing there would be a fair amount of work for Lee and the team to do this, so it might just be a pipe dream of mine, but I'd hope that the feature might be used by others in Europe, or if skydemon etc wanted to include synthetic vision (which is what foreflight uses it for primarily)

Thanks all,

Steve.

[SteveHutt]

Steve,

Don't forget that the US ADS-B system is rather different to that elsewhere. They have ADS-B on 1090MHz that PAW can receive but they also have ADS-B (called UAT) on 978MHz as well, that PAW will not receive. And all the extra service broadcasts (Weather, FIS, etc) are only on that UAT frequency. Plus, as PAW was not designed with UAT in mind, it wouldn't know what to do with the extra data even if it saw it.

There is a ground station rebroadcast of 1090MHz traffic to 978MHz receivers and vice versa, but as I understand it this only happens if you are broadcasting ADS-B Out yourself - I.e. Detection by the ground station of your broadcast on one frequency ( or if you are lucky, another a/c nearby) will trigger the ground station rebroadcast of traffic on the other frequency.

So, if you go flying in the US with a PAW but with no ADS-B Out on 1090MHz or 978MHz your PAW will only detect any nearby 1090 MHz ADS-B traffic and your PAW will only receive 1090MHz rebroadcast of 978MHz traffic if there is another 1090MHz ADS-B broadcaster near enough to you to trigger the ground station rebroadcasts!

Hope that makes sense!!!

Steve

[stephenmelody]

Thanks SteveHutt,

So I should probably look at repurposing the kit I have to build the device you posted about from the EAA recently.

Thanks for your advice!!

Steve.

[Alan Walker]

If we consider Moore's Law (pun co-incidental Lee!) then I suspect this multi-talented team of 'geek pilots' would certainly want to have a bash at this once the current project put to bed.

Nothing would surprise me!

Al

[Paul_Sengupta]

Get another data card.

http://www.rtl-sdr.com/creating-a-fis-b-ads-b-weather-information-receiver-for-pilots-with-an-rtl-sdr/

More stuff in this thread.

http://www.teamkitfox.com/Forums/archive/index.php?t-6847.html

I've been playing with some apps which allow you to do ADS-B-in directly by plugging an R820T dongle into the tablet. Problem is though, you can't feed power in at the same time. Apparently one of the apps does UAT for the US for weather and stuff as well as traffic.

[Andy Fell]

Keep in mind that the 869MHz (the frequency which the P3I associated transmissions are) is not a license free band in the USA.

You may not have been thinking about using the P3I bit in the USA, but it would not be legal there if you wanted to.  The license free band is at 902-928MHz and the rules are quite different to Europe.

[stephenmelody]

I wouldn't be using the P3I component in the US, pretty much everything I've seen seems to have ADS-B out and I'd likely be the only one flying around with the P3I bit, which would make it rather pointless.

I'll probably crack on and build one of these for my US flying and stick with PAW for the UK... http://stratux.me/

[Paul_Sengupta]

As for US tablet software, I have "Avare" which is free.

Do you know or have tried if the Stratux software can use the same Wifi dongle as the PAW? The instructions have a different one. I guess I could try it and see.

[stephenmelody]

It looks the same... it's a UBlox7 dongle that they're referencing... is it different?

I've got the UBlox, once I'm back in the UK next week I'll start my build. I think I've got most of the components. I'll give it a go with SD, Foreflight and I'll try your Avare app too.

[Paul_Sengupta]

The u-blox is the GPS, referenced as a VK-172. Same one as the PAW uses, as are the ADS-B/SDR dongles.

The Stratux project says that it uses an EDIMAX WiFi dongle though.

I've got an RPi 2 here, maybe I'll give it a try. Though maybe with a single receiver it'll work on a B+. Have to experiment.

Avare is on Android, not sure if there's a version available for the iPad.

[stephenmelody]

That's what happens when you misread WIFI as GPS - good point, my eyes must be getting bad!!

I've got an EDIMAX wifi dongle in one of my RPis at home, so I'll just pull it out of that.

I'm guessing the receivers are the same as the ones previously advised for PAW, if so, I've got at least 2 of those knocking about.

If you're going B+, here's some guidance - https://www.reddit.com/r/stratux/comments/3zpr4j/howto_build_stratux_for_raspi_b_armv6/

[Paul_Sengupta]

Cheers, was just thinking about an interchangeable unit, PAW for Stratux, just swapping the memory cards. Also the power draw of the B+ is less than that of the 2, maybe useful in rented aircraft in the US if they don't have a power socket (though I think most of the ones I've flown over the years have had a power socket!). I like the idea of the two receivers, does that need the power of the Pi 2?

[stephenmelody]

I'm going to have it sit on my Anker power pack, I managed to run my old PAW setup with all the bells and whistles for about 4 days straight (it had run out of power by the time I got home on the 5th day).

From what I can see here, it appears it burns through CPU with 2 receivers - https://www.reddit.com/r/stratux/comments/3m8t0u/b_support/

Or you could go straight to the Pi 3??? https://www.reddit.com/r/stratux/comments/4aoocl/need_beta_testers_for_new_image/

[Paul_Sengupta]

Funny thing, I ordered a Pi 2 on the Saturday when they announced the Pi 3 on the Monday! 

I've just built my Pi 2 with the software and in the bootup I see it fails on the "advanced 802.11" stuff. I've tried two Wifi dongles and while the PAW one fails at this point, the other one really fails!  So I think it needs the Edimax. I also read here that he's now coded in support for the built in Wifi for the Pi 3. I guess he could also start supporting Bluetooth GPSs with it.

[stephenmelody]

I'm going to build one up when I get back and will report on how it's doing...