SNS---Simple Navigation System idea

Discussion in 'Instruments / Avionics / Electrical System' started by Aerowerx, Jul 19, 2017.

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  1. Jul 22, 2017 #21

    Aerowerx

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    I have done a bit of reading on Arduino GPS shields and related software libraries.

    There is not much you would have to do other than hook everything together. With some of the GPS units you give them the coordinates of your waypoint or destination and it spits back your course, heading, ground speed, and estimated time remaining. So all you would have to do would be display the data in the desired format.

    I also see that the best choice for the display would be a transflective LCD. This will work in bright sunlight and most of them have a backlight that can be turned on in dim light. There are even some transflective graphics displays, if you want to get extravagant:).
     
  2. Jul 22, 2017 #22

    cluttonfred

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    I think the monochrome OLED displays are also bright enough for direct sunlight and oddly the OLED graphic (pixel matrix) displays are actually cheaper than the character displays. For example, this 1" diagonal, 128x32 pixel display costs just $17.50, includes an onboard voltage regulator and uses only 3 pins to communicate with the board via I2C.

    931-10.jpg

    https://www.adafruit.com/product/931
     
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  3. Jul 22, 2017 #23

    Aerowerx

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    The transflective displays are backed up with a reflector so they reflect back the incident light. They also have a LED back light for dimmer environments

    Not sure if the OLED displays are transflective.
     
  4. Jul 22, 2017 #24

    cluttonfred

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    They are not as far as I know, but since they are tiny LEDs (not backlit LCDs) I think with an anti-glare cover you should be OK, but that's just speculation on my part.
     
  5. Jul 23, 2017 #25

    Pilotgil

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    OLEDs in general are not good in sunlight but some are getting quite good. They are emitters of light so limited. I use transflective LCDs. It's not as easy as just hooking it up but as long as you can write C code it's not terrible. The RPM/EGT system I built was about 40 pages of code if printed.

    FullSizeRender(1).jpg
     
  6. Jul 23, 2017 #26

    cluttonfred

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  7. Jul 23, 2017 #27

    Aerowerx

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    My comment in post #21 refered to deriving the course, heading, etc. from the GPS data. It is done for you if you pick the right GPS module.

    The only C code you would have to write would be to capture the data and send it to the display.
     
  8. Jul 23, 2017 #28

    Aerowerx

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    I saw their web site, but it didn't tell me much. Haven't looked at Mouser or Digikey yet.
     
  9. Jul 23, 2017 #29

    Hephaestus

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    Nixie tubes ;)
     
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  10. Jul 23, 2017 #30

    Aerowerx

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    I think they would get washed out in bright sunlight.

    (And how many on here know what they are?)
     
  11. Jul 23, 2017 #31

    Hephaestus

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    Probably but it would look cool ;) and behind a opaque bit of acrylic they almost resemble 7 segment LEDs. Which might be the best option come to think of it.

    And the steampunk folks would go nuts lol
     
  12. Jul 24, 2017 #32

    Aerowerx

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    Huh? The Nixies I am familiar with have a separate element for each digit, stacked one behind the other. 11 pins on the base. A type of vacuum fluorescent display. Just apply voltage (around 100-150vdc, IIRC) to the digit you want.

    I do have a bunch of 7 segment incandescent displays around here---in a homebrew* frequency counter.


    -------
    *homebrew: What DIY used to be called, among amateur radio enthusiasts.
     
  13. Jul 24, 2017 #33

    Hephaestus

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    Yup those are the ones, I was thinking like a 7 segment in overall look/glow. Other than the curves instead of hard edges - similar visibility.

    Didn't the USSR use them in aircraft displays? I know they were mostly instrumentation in North America.

    I'm no nixie pro - but I do want a nixie steampunk watch ;)
     
  14. Jul 24, 2017 #34

    Aerowerx

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  15. Jul 24, 2017 #35

    Hephaestus

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    26d210443d92325d4aba63c794228f6a--steampunk-gadgets-steampunk-watch.jpg
    See I want like this... But it's vfd and not that cool...

    52eacd4b857bfa5c45242fe799a886c3.jpg
    But these would do... ;)
     
  16. Jul 24, 2017 #36

    Pilotgil

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    With the exception of very primitive data such as COG and GS and PPOS, most modules that I have used do not have databases or any complex user controlled intelligence. Normallly, they output location, course over ground, ground speed, gps altitude, gps time, checksums, etc. Generally, the host CPU provides the UI, database, and display and most importantly, the process for navigating. For me, the SNS needs an aviation database (so you can enter an airport ID rather than Lat/long) , UI, display, system management (checksums, GPS status, error handling, etc.). The prototype that I working on is very simple, enter a airport ID, the system pulls the lat/long from the database, calculates a DTO, and then provides a process for staying on course and the principal navigation data. I normally use Garmin OEM GPS Sensors but just finished my first using a very inexpensive GPS Sensor and have been very impressed. There are no shareware libraries for the graphics modules I use (they fit perfectly in a 2 1/4 inch instrument) so there's a bunch of code to make it work.
     
  17. Jul 24, 2017 #37

    Aerowerx

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    Then it wouldn't be a Simple Navigation System, would it?
     
  18. Jul 24, 2017 #38

    gtae07

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    Depends how you define "simple".

    I like to look at operational simplicity and ease of use. By that measure, a moving-map handheld GPS or Android/iOS app simply blows away a text-only system that requires lat/long coordinates. I've used a text-only aviation GPS before, and for all its "simplicity" it's a lot easier to goof up and miss a small-ish but eventually significant mistake than it is on a moving map.
     
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  19. Jul 24, 2017 #39

    Aerowerx

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    By simple, I mean not having to program the database with a list of ICAO designations and corresponding lat and long, and database search routine. And displaying the essential information, namely bearing to destination (and heading, speed, and time to arrival would not be too difficult).

    Take a look at these, taken from this web site:
    (My emphasis)

    The GPS receivers already spit out the needed information.
     
  20. Jul 24, 2017 #40

    gtae07

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    So you mean, simple for the programmer.

    Not so simple for the pilot, who would have to maddeningly enter a long coordinate string with a push-and-turn knob, instead of dialing a simple three- or four-character identifier. Or better yet, just typing it in on a touchscreen, and seeing a map!
     

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