Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Innovative Mod for Long Range FPV

Discussion in 'Phantom 2 Vision Mods' started by PVFlyer, Mar 3, 2014.

  1. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    I'm glad to be the first post in this new subforum.

    After discovered LHCP antenna in Vision camera back in December 2013, I DIY a pair of helical antennas to cope with Vision camera. I managed flying stock P2V aircraft with the homebrew helical for 2.7 KM range by FPV. I think I'm more or less done with the stock P2V.

    I have been planning an innovative mod on the P2V aircraft targeting ultimate FPV range of P2V as long as the battery last and future ground station iPad app. I estimate P2V can fly 6 KM range (12 KM round trip) at full speed with safety 20% battery remained if it's not too windy.

    The idea is to convert standard 802.11n Wifi protocol to other proprietary protocol for long range transmission from the aircraft, and then convert the proprietary protocol back to standard Wifi protocol on the ground AP/repeater for Vision app running on Android/iOS devices. This mod/project is called PVBridge.

    DJI LightBridge performs 1.7 KM range with rubber ducky antennas (probably 5 dBi) on ground station and 5 KM with directional antennas. I target 2 KM range with 5 dBi rubber ducky antennas on ground station and 6KM with helical or other directional antennas. Obviously, P2V could not achieve 1080p full HD for sure.

    There are 3 key factors for long range FPV:
    1. 5.8G control link - can reach 3-4 KM with directional antenna, and it may not be an issue if using ground station iPad app for waypoint navigation;
    2. 2.4G Wifi FPV link - the focus of this PVBridge project, hope to control camera tilting and aircraft yawing by FPV link during waypoint navigation if it goes beyond 5.8G control link;
    3. 5200mAh battery - no solution so far;

    I know this is a challenging project that may last months, and I might not be success at the end of the day. Anyway, I am willing to give it a try and keep my fingers crossed.

    I will keep updating this and the following posts with my progress and thoughts.
    • Stage 1 - Hack Vision Camera & Change Configurations
    • Stage 2 - Build a Long Range Wireless Bridge
    • Stage 3 - Mid Range FPV Test
    • Stage 4 - Long Range FPV Test
     
  2. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Stage 1 - Hack Vision Camera & Change Configurations

    This is the most challenging task so far. A friend of mine helped to hack the Vision camera with a VERY stupid way, but it works. We managed to change Wifi channel to avoid those crowded channels and interference. We have been exploring a smarter way of doing this, as I need to change various configurations in the field for testing.

    I prefer to hack the camera by simple Wifi connection as I did on AR.Drone. AR.Drone is an open platform running Linux without password protection. I can run some Linux commands or scripts to change the required Wifi/network configurations. My friend even built a homebrew app to simplify the process. A boosted AR.Drone with cloverleaf antenna can reach 2KM range.

    P.S. Please don't ask the stupid way to hack Vision camera, I can guarantee >50% chance breaking the camera if do so.

    Will update if any progress achieved.
     
  3. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Stage 2 - Build a Long Range Wireless Bridge

    I have been exploring various wireless bridges. The basic requirements are as below.

    1. Weight: <100 gram
    2. Output power: >200mW
    3. RX Sensitivity: -95 dBm
    4. Protocol: Support both standard Wifi and other long range protocol
    5. Do not need expensive CP antenna, I hope to first test it with a dirt cheap $1 rubber ducky antenna on P2V aircraft. Of course, CP antenna will help a lot in terms of video stabilization.

    Will update if any progress achieved.
     
  4. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Stage 3 - Mid Range FPV Test

    Will update if any progress achieved.
     
  5. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Stage 4 - Long Range FPV Test

    Will update if any progress achieved.
     
  6. BobUnplugged

    Joined:
    Nov 17, 2013
    Messages:
    235
    Likes Received:
    24
    Will you update us if any progress is achieved?
     
  7. Pull_Up

    Joined:
    Nov 5, 2013
    Messages:
    3,684
    Likes Received:
    48
    Location:
    South Oxfordshire, UK
    <wipes coffee spray from laptop screen>
     
  8. tizzl10

    Joined:
    Feb 4, 2014
    Messages:
    882
    Likes Received:
    1
    lolololol.
     
  9. ResevorDG

    Joined:
    Feb 1, 2014
    Messages:
    565
    Likes Received:
    23
    Location:
    Phoenix, Arizona, USA
    I am shocked! With you being from South Oxfordshire, I always thought that was English tea in your mug.
    All you need now is a pair of cowboy boots.
     
  10. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    With help of a friend (who is a Linux expert), we managed to get access to Linux console of the camera over Wifi. This is a crucial step to proceed further for changing the camera configurations easily in the field. We have been working on the next step to grant admin rights to take full control of the Linux.

    Imagine, accessing in the Linux console is similar to getting in front yard of a house by opening a gate with a magic key (BTW I own that house). We figured out the magic key, and we can open the gate now.

    Then we need to open the door of the house with another key (admin password). DJI uses a pretty secured way to build the door lock. My friend wrote a program to derive a key for opening the door. I believe we can work out the key in the next few days.
     
  11. Pull_Up

    Joined:
    Nov 5, 2013
    Messages:
    3,684
    Likes Received:
    48
    Location:
    South Oxfordshire, UK
    This is very interesting. What kind of configuration settings are you hoping to change?
     
  12. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    I like to change 2 configurations for the time being.

    (1) Wifi channel - By default, my P2V is always on channel-1 (2.412GHz). It will probably be forced changing to other channels automatically if channel-1 is occupied by other APs/routers, but it's already been too crowded - poor SNR. Furthermore, I always fly with other RC friends who are using conventional 2.4G transmitters (such as Futaba, JR, Spektrum, etc). These transmitters generate a lot of 2.4G interference likely from Wifi channel-1 to channel-9. I prefer changing it to channel-11 or even channel-13 (channel-13 is legal in our country). This would improve SNR a lot by changing to less noisy frequency. The environment RF noise is out of my control, but I can control my frequency in use.

    (2) Wifi mode - By default, P2V is in AP mode, while Android/iOS devices are clients connecting to P2V's AP via repeater. I like to change P2V from AP mode to client mode. This allows me to build a long range wireless bridge much easier.

    (3) Grab realtime GPS data from P2V (no configuration change) - Collect GPS data to show P2V flight path REALTIME on Google map. Obviously, I can also record GPS data on Android/iOS devices or memory card similar to Flytrex for playback later. This can also work around >1KM showing "N/A" feature. It's NOT a bug, while DJI coded this feature explicitly in Vision app.

    And a lot more.
     
  13. Pull_Up

    Joined:
    Nov 5, 2013
    Messages:
    3,684
    Likes Received:
    48
    Location:
    South Oxfordshire, UK
    Very interesting, thanks for keeping us updated with your progress.
     
  14. antennaman

    Joined:
    Feb 9, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    Palo Alto
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    It's not too tricky to mod the dji app to log the gps etc data. Not tried viewing it in realtime though!
    Presumably you've accessed the PV network by ssh into the repeater?
     
  15. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    Never bothered of modding the Vision app as it's non-open source. Even like Parrot's AR.Drone - FreeFlight is open source, but it's hard to keep SDK updated.

    There are multiple of ways for getting GPS data from P2V, instead of installing a second GPS device on the aircraft.
     
  16. antennaman

    Joined:
    Feb 9, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    Palo Alto
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    Yes, not point in replicating the GPS when you can just log it to a file.
    I'll ssh into the repeater, see if the channel settings are easily adjusted there.
     
  17. ClimbrJohn

    Joined:
    Jan 27, 2014
    Messages:
    52
    Likes Received:
    0
    Location:
    Denver, CO | 39.7537, -105.0057 | 5,280'
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    I never could figure out the credentials for logging in via SSH or the web interface of the AP. Could you please share? Thanks!

     
  18. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    Re: Stage 1 - Hack Vision Camera & Change Configurations

    AFAIK, the DJI range extender is an "universal repeater", which is NOT an AP. The AP is on Vision camera. I have never bothered to hack the repeater, as I don't use it anyway. I'm focusing on the camera, and I think it's way more complicated involving custom SSH port, magic key cracking in console, admin password, etc.
     
  19. djscoutmaster

    Joined:
    Dec 26, 2013
    Messages:
    52
    Likes Received:
    0
    This is all Very Very interesting. Could you explain your process for then ssh into the pv2 camera? Also have you been able to retrieve gps info or intercept commands from the app? I'm looking for the ability for a second homegrown app to access similar info or duplicate info from the existing app and even act on it. Such as changing camera settings while the pilot focuses on flying or even Datalogging to look back and understand what happened.
     
  20. PVFlyer

    Joined:
    Jan 27, 2014
    Messages:
    1,484
    Likes Received:
    125
    Location:
    Hong Kong
    The process used to hack Vision camera (initial firmware) is no long working on latest firmware. A friend of mine helps me to work on the latest firmware.

    GPS data sending from P2V aircraft to Vision app is un-encrypted. You may setup a "proxy" and force network traffic routing through the proxy to log GPS data on either non-stock AP/repeater (probably need a USB port for thumb drive to store the log) or rooted Android.