My Attempt at a $115 ADS-B Receiver Build for Foreflight

Discussion in 'Technical Corner' started by JoseCuervo, Aug 17, 2015.

  1. denverpilot

    denverpilot Tied Down PoA Supporter

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    Plug it into a TV via HDMI with a keyboard in the USB, log into it, and see if it's throwing any errors? :)
     
  2. murphey

    murphey Final Approach PoA Supporter

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    Looks like the pi is dead. Red and blue light, but no signal. Need to try it on the monitor to make sure nomother signal is interferring. tomorrow, not tonight.
     
  3. denverpilot

    denverpilot Tied Down PoA Supporter

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    There were some changes to the code base to support Pi 3 recently. Judging by the conversations in the Slack channel, most of the developers are like the ones at my work and are new hardware addicts and always have new toys, so... Perhaps they have a problem with Pi 2.

    I haven't really paid attention to it since my last update but someone was asking in Slack just before the weekend. Don't know what the outcome was but watch out for that in release notes and stuff.

    Worth a look at the boot to see what's barfing... That, of course, would be the definitive answer. :)
     
  4. flhrci

    flhrci Final Approach

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  5. murphey

    murphey Final Approach PoA Supporter

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    Hooked it up to the tv last night...dead. Just happen to have a spare Pi2, will,see if that works. I tried both V o.8 and 1.0 with no luck. 0.8 was working last time I turned everything on.
     
  6. murphey

    murphey Final Approach PoA Supporter

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  7. denverpilot

    denverpilot Tied Down PoA Supporter

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    I always keep a boring old copy of Raspian around on a memory card that I know works, so I can tell if any other SD cards aren't happy by eliminating that as part of any troubleshooting on a RPi. Pop in Raspian and see if it boots with all the USB devices removed.

    If the other card ends up being the problem, the fix is usually just a "dd" away. Heh. Takes about ten minutes if I already have the image downloaded. And I keep all the images on a project like this so if they "release" something that doesn't work I can just downgrade and wait. Not just Stratux, all of these projects.

    I haven't had an RPi die totally yet, but I do have one with a flakey SD slot. RPi isn't very robust. Numerous friends have had them die doing radio stuff with them when lightning comes to visit.

    Totally dead like yours, but with lights lighting up, I'd unplug all the USB stuff and see if it'll boot without them. They're very sensitive to under-voltage caused by a weak power supply that can't provide enough operating current. If a USB device drags the power rail down they don't work until it's unplugged. The CPU rail is the same as the USB rail, they're not isolated in such a small cheap gadget.
     
  8. murphey

    murphey Final Approach PoA Supporter

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    HDMI plugged into a standalone monitor.
    USB keyboard.
    5v/1amp power supply, fully charged.
    Nothing else connected.
    Red LED and blue LED lit where appropriate.
    Neither Pi2 displayed anything on the monitor.
    Tried both v0.8 and v1.0 SD cards, same result. zip. nada.
    I need to finish up a website, then will head out to do some shopping (grocery store at the top of the list) then over to Microcenter for another pi. I also think one of the SDRs are dead - no white LED when the whole thing was powered up.

    I have all the stable releases going back to last August but v0.8 seemed to work really well.
     
  9. denverpilot

    denverpilot Tied Down PoA Supporter

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    Not normal to have two boards fail simultaneously. But that's from the guy who always has something break every time he goes to Nebraska other than this year, so meh.
     
  10. murphey

    murphey Final Approach PoA Supporter

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    But dead board was the problem. Picked up a Pi3 at microcenter today, works great. Of course now one of the SDRs is dead.
     
  11. denverpilot

    denverpilot Tied Down PoA Supporter

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    What is wrong with the power at your house?! Hehehe. Wow.
     
  12. Cap'n Jack

    Cap'n Jack Final Approach PoA Supporter

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    @weirdjim

    Would an inverted F antenna work for this purpose? I've seen designs that are compact and can handle 3 frequencies; commonly used in cell phones.

    Here is one: https://www.google.com/patents/US20030206136

    If I did the math correctly, the measurements for Figure 4 (figure 4 in the link) would be 7.6 cm (978 MHz) for #22, 6.8 cm for #23 (1090 MHz), and 5.3 cm for #24 (split the difference in the GPS wavelengths). This looks like it could be cut from a single piece of metal and folded. That gives one antenna for all 3 receivers (2 ADS B, 1 GPS) about 5 inches long.
     
    Last edited: Sep 5, 2016
  13. Axtel4

    Axtel4 Pre-takeoff checklist

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    I have been experimenting with a couple of printed Inverted F designs. One subtle thing not mentioned in the referenced Patent is the Quartwave matching element. This is the eletrical length from the center of the ground pin (25) to the feed point (21) and is typically one quarter wavelength at the highest frequency. Also not explicitly stated is the deminsions at the end of 22 and 24. These serve a couple of purposes, 1) as stated they can increase the bandwidth, but 2) they are also used to match the longer antenna element to the shorter mounting stub.

    Another item is as the frequency is decreased, the spacing between the radiating element and the ground pane will need to increase. A startng point would be to split the quarter wavelength matching element into three segments. One segement sets the height above the ground plane and the other two segments set the length of the "cross bar" from the ground pin to the feed point. At 1090 MHz, this will set the readiating element height at app. 0.9" and the "cross bar" length at approximately 1.8" Alternately, one could split the quarter wave section in half and set the radiation element 1.35" above the ground plane. This will tend to "flaten out" the radiation patteren of the antenna. Most of the time, in the final design, the height of the radiating element above the ground plan is driven by the dimensions of the enclosure and a compromise of the radiation pattern.

    If will help, you can also visualize an IFA as a J Pole antenna folded over a gound plane.
     
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  14. Cap'n Jack

    Cap'n Jack Final Approach PoA Supporter

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    @Axtel4 :

    That is good information, thanks much. I'd probably try to make one of the other designs as I only have the 978/1090 receivers. Those designs in the patent look interesting since they are compact and look easily made by cutting out some sheet metal and folding it over. However, patents don't always mention everything. I sort of do see the J pole antenna there.
     
  15. DrewG

    DrewG Pre-takeoff checklist

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    I'm toying around with the idea of building a Stratux unit myself or buying a pre-built one, like @Archammer has available. My issue is whether or not I want an onboard GPS or remote-mounted. There seems to have been issues with the onboard types, according to my browsing of Reddit threads, but I'm not sure how prevalent this is. Onboard certainly saves space and wires, but reliability is king to me. What experience do you all have with one or both?
     
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  16. Cap'n Jack

    Cap'n Jack Final Approach PoA Supporter

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    I use a Bad Elf external GPS since my iPad doesn't have cellular, from before the Stratux. It works quite well. I'm not sure if that is what you meant by "remote mounted".
     
  17. denverpilot

    denverpilot Tied Down PoA Supporter

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    iPad has cellular here, it's just far too useful to me for various reasons and only costs me $10/mo or $120/year to keep it on (plus whatever difference there was in initial price of the device, but that was cash and burnt long long ago), so I don't care at all to have a GPS connected to the Stratux.
     
  18. GeorgeC

    GeorgeC Administrator Management Council Member PoA Supporter

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    I just use the iPad's builtin gps and call it a day, no cell service.
     
  19. DrewG

    DrewG Pre-takeoff checklist

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    I have a Bad Elf, as well. My iPad mini that doesn't have built-in GPS or cellular. I had been using an old Stratus 1, but it's been VERY hit-and-miss in terms of connection...even without overheating. By "remote mounted" I meant a separate GPS connected to the Stratux via a cord. If you've seen the FlightBox Stratux build kit, remote-mounted the only type of GPS they have.

    I'd be fine just using the Bad Elf and a Stratux box, but would be concerned about battery life on the iPad running items through both bluetooth and wifi. Maybe it's a negligible difference - and maybe I just prefer an "all-in-one" solution. I just know that the old Stratus 1 has been giving me fits and has become fairly unreliable.
     
  20. Archammer

    Archammer Cleared for Takeoff

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    The ADSBIN's do have built in GPS. :)
    The reception is ok on the ground and very good in the air. As the technology improves it will just get better and better.
     
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  21. Cap'n Jack

    Cap'n Jack Final Approach PoA Supporter

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    Battery life using the Stratux and Bad Elf have been in excess of 5 hours for me running ForeFlight, but using an older iPad..
     
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  22. bgdriveway

    bgdriveway Pre-takeoff checklist

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  23. avongil

    avongil Pre-takeoff checklist

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    Here is mine. Parts came in, had it assembled in about 15 minutes. So easy!
    https://goo.gl/photos/zi5vscdNaRujhPjp9

    It seems like port 4,000 is the only one dumping data, so listen on that one.
     
  24. BillTIZ

    BillTIZ Final Approach

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    Interesting box configuration.

    I upgraded to the RPi3 and Nano NooElec receivers and antenna recently. I had the receivers side by side and they put a bit of strain on the internal antenna cables. I noted a different configuration over each other which reduced the cable tension.

    In the process of working the configuration change, I cracked the microSD card. Nothing worked.
    I was able to download the latest image file and rebuild the SD card. All is fine.

    Recent trip from LAS to PRC for the AOPA Fly-In, the system worked great.
    I run an IPad Air2, no GPS, so I have a Bad Elf Pro+ on Bluetooth.
    With 4 hrs round trip I estimate the Stratux used between 6000-7000mAh on my 10,000mAh battery. Based on the lights and charging cycle after I got back.

    My iPad was down to 34% battery remaining after 3 hours, so I plugged it into a spare battery pack I brought along. Make sure your battery packs can push better than 2.1A to charge an iPad.
     
  25. denverpilot

    denverpilot Tied Down PoA Supporter

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    Or at least can do 1A and keep up with the rate of discharge. But the full 2A is better.
     
  26. avongil

    avongil Pre-takeoff checklist

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    Pretty good fit inside...
    When Time permits I want to redo the case to fit the battery under the unit and a steel plate some place so the external GPS has a place to rest if not used remotely. Found case on thingiverse for quick printing. https://www.thingiverse.com/thing:1707442
    Beware though, the screws are difficult to find. Needs a bit of a redesign.

    Top off picture added: https://goo.gl/photos/zi5vscdNaRujhPjp9
     
  27. BillTIZ

    BillTIZ Final Approach

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    I had it plugged into a 2A rated USD port, it only slowed the rated of discharge.

    I did learn that the USB port on the IFD540 will sustain an iPad, but not charge it.
     
  28. denverpilot

    denverpilot Tied Down PoA Supporter

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    Hmm. That sounds like a port that can give 2A but doesn't implement the oddball Apple resistor setup that tells the iPad it can go full rate.

    There's folks that sell little adapter cables that'll force that issue, and some of those even have current meters in them so you can check, on eBay and elsewhere, pretty cheap.

    It really should slowly charge up at 2.1. Not fast if you have the brightness all the way up and FF crunching away and the internal GPS humming. But up should be the trend, not down.
     
  29. BillTIZ

    BillTIZ Final Approach

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    Roger on up being the desired trend. I reduce operations to FF only, but run the Bluetooth for my Bad Elf GPS receiver and need the wifi for Stratux. Sometimes the electronic E6B might be on in background. I'm using an Air2.

    I had not heard of the special cables to strick 2A to 2.1
     
  30. denverpilot

    denverpilot Tied Down PoA Supporter

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    Actually I was thinking the older iPads. Newer stuff you have to get an Mfi licensed cable. Without it the newer Apple stuff won't even attempt the high current rate. I forget where the cutoff on that is on the models, but it should be pretty easy to look up.

    There's various info about it on the Net, but the big kicker is folks who mistakenly grab their older iPhone cables and plug in iPads with them. That can cut the charge rate in half while still looking like the higher rate on the screen.

    Here's a couple of articles with ideas for reasonably priced high current stuff.

    http://m.thewirecutter.com/reviews/best-usb-car-charger/

    http://m.thewirecutter.com/reviews/best-lightning-cable/

    They lean toward Anker brand on most of their articles but I've had a couple of their devices and they're fine -- and not horribly priced.

    But they also point out what they use to test with -- there's a bunch of little in-line voltage and current testers and I have a couple from different cheap Chinese sources (one is a Drok brand, I forget the other) which lets me plug them in and see what's really going on.

    I like having the "test gear". Makes figuring out if I grabbed the wrong cable or charger pretty easy, since I have various stuff lying around here.

    Other tricks: When wall charging, the larger iPad chargers at 12W charge the iPhone a lot faster than the smaller cube chargers the phones (used to?) come with.

    And some laptops can hand out decent charge rates on their USB ports and others can't. Even some older Apple MacBooks can't do it right or even do different rates on different physical ports.

    All of the above may be wrong. Ha. I just hook up the tester and figure out if it's charging at the rate I want and swap stuff around until I get the right combo. I still have a lot of old or cheap cables around and sometimes I want the devices plugged into dumb car stereo ports that don't provide much current but I'm playing the audio through them.

    I have some "known fast" chargers and cables that stay put scattered around the house and a known good combo in my portable battery that's mounted in my Straux case and a known good cable that stays with the Stratux.

    Then there's other stuff scattered around that I know is either not right, or I don't care, in locations where I don't usually charge up or in various bags, etc.
     
  31. bgdriveway

    bgdriveway Pre-takeoff checklist

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    The Stratux is operational, though I still have to go fly with it. Cost for parts that I paid was $142.10 including a $32 battery pack that will be used when I mount the device somewhere in the back seat of the plane. Right now I have it running on a wall outlet or cig plug. Traffic works really well in my living room. Might have something to do with the center of SDF being less than 2 miles from my house. And UPS planes leaving. Weather is spotty right now, in the living room. I did just add alum. tape for a ground plane on the antennas and seemed to help.

    Using it in FltPlan Go on an Ipad Air2. Took me awhile to go find the FIS-B update rates. For a bit I thought the thing wasn't working. Why would I get a TAF at ORD but nothing at SDF?
     
  32. Jim Blankenship

    Jim Blankenship Filing Flight Plan

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    I'm new to this board. This is my first post.

    I read most of these 27 pages of this thread and it's very interesting. It makes me want to build my own just for fun. Looks pretty simple.

    I just bought my Stratux system from everlastconcepts.com. I can't post a link because I don't have five posts yet. :(.

    They sell a fully assembled system that includes WAAS GPS, case, two high-gain antennas (978 and 1090 MHz), and a 6000 mAh USB battery pack for $215. There is a coupon listed on the site that's good for a $10 discount. Shipping is $14. One year hardware warranty.

    On the web site, it says, "For every unit bought: $10 goes directly to cyoung (the creator of Stratux) and another $10 gets set aside for a UND Aerospace Scholarship Fund - to fuel the next generation of professional pilots."

    It's just plug-in and go. Nothing to assemble. It has a clear case with a big suction cup and fan. I haven't tried it out in the airplane yet.

    I tried with with both Avare and FltPlan Go and it works with both.

    It came with an 8 GB SD card. The filesystem is only 4Gig and it filled up quickly due to the logs. I just used gParted and expanded it to the full 8Gig and now I have lots of room for whatever else I need.
     
    Last edited: Nov 21, 2016
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  33. vkhosid

    vkhosid Cleared for Takeoff

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    Looks like the AHRS functionality of the stratux project is finally starting to show some promising results! For those that are following the slack thread, one of the contributors there has developed code that uses a combination of GPS data and data from a barometric sensor to successfully implement AHRS into the stratux box.
     
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  34. Jim Blankenship

    Jim Blankenship Filing Flight Plan

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    I was able to use the Stratux unit in the airplane. I was able to get traffic and weather. It works great. A wonderful cockpit resource. I find that using it with my phone works ok, but the screen is just too small to be practical. I switched to an 8-inch Android tablet and that works wonderfully.

    Being able to get winds aloft, METARs, TAFs, and a "radar picture" of the weather in-flight is *great*.

    Looking at the screen that lists all the ground towers it connects to, there are dozens!

    I'm using the Avare app.
     
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  35. denverpilot

    denverpilot Tied Down PoA Supporter

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    So you're saying it won't work inverted? (The always much touted reason for having an AHRS in a portable device. "Safety when everything else fails...")
     
  36. vkhosid

    vkhosid Cleared for Takeoff

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    I'm not saying anything. I just happened to log into the Slack chat about AHRS, and it looks like they're getting some great results. Just figured I'd pass on the good news.
     
  37. Flying_Nun

    Flying_Nun Pre-takeoff checklist

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    Rebuilt my box with new components including AHRS (which seems a little wonky - climb indicated when I would expect descent). Picked up a few airliners with the unit sitting in my kitchen.

    Version 1
    [​IMG]

    Version 2
    [​IMG]


    Sent from my iPhone using Tapatalk
     
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  38. ircphoenix

    ircphoenix En-Route

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    I got the upgraded GPS dongle with the larger antenna. Works way better than the tiny one. Probably not as well as the remote mount, but I didn't want all the extra cable.
     
  39. Flying_Nun

    Flying_Nun Pre-takeoff checklist

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    I ended up zip tying the battery and case together. Then velroed the GPS antenna to the top of the case. Twist tied the extra GPS and power cables together. Shouldn't be to messy.
     
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  40. ircphoenix

    ircphoenix En-Route

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    I did the same with the case and battery. The plan with the GPS antenna was to do exactly the same... but then I found the other internal module. We'll see how happy I am with it.