FPVLAB

image
Page 1 of 9 123 ... LastLast
Results 1 to 10 of 88

Thread: DIY (5 way) Diversity Controller

  1. #1
    Navigator cardboard_boks's Avatar
    Join Date
    Nov 2011
    Location
    Wellington NZ
    Posts
    891

    DIY (5 way) Diversity Controller

    I have been using this for some time now and recently posted pics in the "show us your ground station" thread. Interest was shown in the project so what better way to share the code/schematics then in a thread of its own.

    I was most intrigued by people asking weather the switching worked well as I use CP antennas which apparently have none linear RSSI values. I believe the act of smoothing the incoming data and limiting the speed of switching helps get accurate switching. This is backed up by graphing the values throughout an average flight.
    file below.

    This is an Arduino based video switcher that relies on RSSI.
    It uses the following main pieces of hardware.
    -atmega 328p
    -4051 Analog Multiplexers
    It was built around a number of specifications that I needed but other may find useful as well.

    5 video/audio/RSSI inputs that get switched between.
    3 video outputs (via video amps) for DVR, goggles and an external screen.
    2 audio outputs, one compatible with the ezosd telemetry link, the other for the DVR.

    And some of the code features.
    -2 modes, auto and manual (indicated by leds). Kinda self explanatory. when
    switching from auto to manual the last good receiver is used as the first
    channel selected then you just scroll through the channels.
    -led for each receiver, solid indicates the receiver is in use, any receiver with
    a "bad" RSSI blinks
    -buzzer, if the receiver in use has bad RSSI it beeps in time with flashes.
    -each RSSI is averaged over 50 cycles and inputs are switched only after a
    minimum of 500ms has passed since the last switch so switching isn't
    erratic.
    -startup routine- each channel is cycled for 1 sec to allow conformation of
    operation followed by startup beep sequence. If the switch for auto/manual
    mode is in manual on power up the unit wont start until it is set to auto,
    to avoid taking off with manual mode selected and not gaining the use of all
    receivers.
    All RSSI values and other related information is sent out over the serial line for logging in the field.
    I also have a switch so I can chose to view ether the live feed or the DVR
    overlaid feed through the goggles, to confirm the DVR is recording/view
    playback.
    And a switch linked to the arduinos reset pin for programming and field
    reset.

    As a bonus the code/hardware has never crashed or locked up, even during initial coding.

    All the coding is my own.
    The video amps are based on this circuit
    http://users.otenet.gr/~%20athsam/vi...l_emphasis.htm
    But has been modified with help from a fellow FPVer.
    I used PCB artist for all the layouts which is available here
    http://dw.com.com/redir?edId=3&siteI...tist%26dlm%3D0

    code and scehmatics are avalible from this link
    https://dl.dropbox.com/u/11371953/DIY%20Diversity.rar

    This was the prototype board.




    And this is the one that is now installed in my GS




    Said ground station.



    from bottom left in clockwise direction.
    433mhz lost model tracker
    box for storing bits and peices
    fatsharks
    EZUHF
    wires
    antennas
    reciver box
    DVR and switcher in box
    switches and leds
    more antennas.


    Average deployment.


    Receiver box with antennas.

    exel file of RSSI values over an average flight.
    https://dl.dropbox.com/u/11371953/4w...i%20graph.xlsx

    And proof it works, switching is all bar unnoticibale.



    This is very much a DIY project, although things work great for me I did a it of tweaking here and there during the build that may not be reflected in the documentation. The code should be sound but test your hardware thoroughly first.
    Last edited by cardboard_boks; 21st February 2013 at 09:40 AM.

  2. #2
    Navigator Red Dog NZ's Avatar
    Join Date
    Jan 2013
    Location
    Wellington NZ
    Posts
    290
    Thats a sweet setup. Gotta love RYOBI, good quality cases. Going to enjoy checking this system out.

  3. #3
    Pilot
    Join Date
    Feb 2012
    Location
    TN, USA
    Posts
    1,096
    Nice!

    So If im looking at it correctly, your video amp circuits are on the "back end" just before it goes out to the devices? I was thinking of making a super simple one with a picaxe chip and 4052 (dual 4 way ana/digital MUX/demux) but I think the PIC will be too slow. The coding was able to run stable 8mhz, and I took 5 RSSI samples before switching. I havent ordered the MUX chips yet, but now that I saw your build using the 4051 I think ill continue... I do have a Arduino Pro Mini 328 that I may try to use, but never programmed Arduino yet.

    The integration of the AMP's and Diversity is awesome! I would probably have to go with 4 video outs though (Recorder, Monitor, Goggles, Guest goggles)

    Chris

  4. #4
    Navigator cardboard_boks's Avatar
    Join Date
    Nov 2011
    Location
    Wellington NZ
    Posts
    891
    Yes the amps are right before the outputs. The 4051 have ~300ohms of resistance through them which means without the amps the video is very dark. Also by using amos you can drive as many outputs as you want. It should be pretty easy to spot one of the video amps and duplicate it, if you need a hand I think I have just the video amp diagram somewhere.

    There are better options that don't require a video amp such as using
    -max4547 video switchers
    with
    -AD812 video opamps

    I used the 4051s as they were available locally

  5. #5
    FPV ROO speedstep's Avatar
    Join Date
    Jan 2012
    Location
    Australia
    Posts
    227
    Respect!! Nice built... but ezuhf why do you use 5,8ghz for video?
    www.youtube.com/user/speedstep23

    Nothing Yaws like a Disco

  6. #6
    Navigator cardboard_boks's Avatar
    Join Date
    Nov 2011
    Location
    Wellington NZ
    Posts
    891
    Thanx it was a fun project.
    I can easily outfly 2.4 control with 5.8. Frsky 2 way gear starts failsafing at ~2km on an average day. I have had 5.8 (200mw, 7 turn helical) to 6.5km and that had perfect image and 433 is the easiest way to get control at that distance.
    Once you start getting out that far a set of helicals fanned out in an arc is the cheapest way to widen were you can fly thus diversity.
    And you may have noticed that I only have 4 antennas but the capacity for 5, apart from only have 4 receivers I am planning on making the 5th onput part of an antenna tracker. Seeing as I have the EZOSD with its telemetry downlink already it makes scenes to use there antenna tracker.

    May seem overkill to some but I enjoy tinkering and playing, my style of flying benefits from some of these features as well.

  7. #7
    Navigator cardboard_boks's Avatar
    Join Date
    Nov 2011
    Location
    Wellington NZ
    Posts
    891
    In case anyone was wondering why I don't move to another video freq

    900mhz is illegal in NZ
    1.2ghz only 1 channel is legal and I frequently fly with someone using this channel
    2.5ghz he flys on 2.4 and so do I with some of my other FPV models
    5.8ghz only one left and I have a fair bit invested in gear as well.

  8. #8
    Pilot
    Join Date
    Feb 2012
    Location
    TN, USA
    Posts
    1,096
    Cool, Thanks for the info!

    After looking at the video switcher, and the amps, I think ill just make them how yours is (with an addition to select RX for different frequencies)
    Last edited by chanyote66; 22nd February 2013 at 01:19 PM.

  9. #9
    Navigator Red Dog NZ's Avatar
    Join Date
    Jan 2013
    Location
    Wellington NZ
    Posts
    290
    Quote Originally Posted by cardboard_boks View Post
    In case anyone was wondering why I don't move to another video freq

    900mhz is illegal in NZ
    1.2ghz only 1 channel is legal and I frequently fly with someone using this channel
    2.5ghz he flys on 2.4 and so do I with some of my other FPV models
    5.8ghz only one left and I have a fair bit invested in gear as well.
    Thats awesome info, especially about the 900mhz. Could have been messy. + 5.8 can have multiples flying together without interferance right..

  10. #10
    Pilot
    Join Date
    Feb 2012
    Location
    TN, USA
    Posts
    1,096
    Quote Originally Posted by Red Dog NZ View Post
    Thats awesome info, especially about the 900mhz. Could have been messy. + 5.8 can have multiples flying together without interferance right..
    Yes...
    Depending on legal bands, it is usually safe to fly 2 channels off...

    Example:
    Plane 1 = ch1
    Plane 2 = ch3
    plane 3 = ch5
    plane 4 = ch7 or 8

    If you use two channels closer together it can get cross talk.

Page 1 of 9 123 ... LastLast

Similar Threads

  1. USB Joystick controller.. DIY
    By RandallJ in forum DIY
    Replies: 0
    Last Post: 4th February 2013, 12:40 PM
  2. Your first flying multicopter's controller
    By nolaspring in forum OSDs & Flight Controllers
    Replies: 13
    Last Post: 31st December 2012, 02:26 AM
  3. All-in-one controller?
    By texasyeeha in forum IFR - Video Link Discussion
    Replies: 2
    Last Post: 3rd April 2012, 03:44 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •