Just spent a couple of hours getting my head around the MultiWii V2.1 serial protocol.  This involved looking at EOSBandi's MW-WinGUI Visual Studio c# code and adapting the essential bits I need to a simple test VB 2010 app.  The app sends the commands to get the GPS bearing and distance to home as well as the Baro altitude.  The BT module connected to the Pairs MultiWii board sends back the info I requested and shows these values in textboxes on a basic form.

That's part one out of the way.

Next phase will be adapting that code, now that I understand how it is done, to Arduino code.

The code will output PWM on two digital ports to drive two servo's to position the patch antenna.  Rather than use the short range BT module I will set the MultiWii code to use 57600 rather than 115200 and hook up my XBee Pro module.  The other XBee will be connected to the Arduino tracker.  So the tracking Arduino will be asking the Hexacopter where it is and with any luck the Hexacopter will say "here I am".

If anyone is a VB programmer I can post the important bits here if they want to roll their own PC based MultiWii ground station.  Very easy to code once you know the binary protocol.

If I get the Arduino code happening in the next few days I'll post it here.

Also, if anyone is aware of an existing tracker for the MultiWii controller which uses the V2.1 protocol (not via OSD's fitted with GPS's and telemetry sent via audio) please let me know about it.  

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  • I am working on it right now., first version will be without telemetry section
  • Hi Eugene, how's this app going?  So much potential there.  Looks like it will be awesome.  Well done.

    I'd be more interested in the live telemetry info overlaid on a map.  I think the best set up would be to use long distance radios between drone and base and then the base retransmits a short distance via the bluetooth module to the ios device.  I could sit there with the live LCD on one side and the ios device to the side of it showing me where I was on the map.  Come to think of it I could probably do this anyhow just by retransmitting NMEA to the ios device and somehow make the ios device think it was a bluetooth GPS.

  • some one was taking about iOS client for Multiwii, so i decided to show my application.

    RCGroups thread

  • I do have an old Sanwa Tx I could swipe the joystick out of and remove the spring from the y axis.  I will need 5 wires for the three potentiometers (throttle, cam pitch, yaw override).  When the main joystick yaw is centered, input from the collective joystick left/right controls yaw.


  • Might source a 2 axis joystick about the size of a normal Tx gimbal and attach it to the end of the collective arm.  I can then use my left thumb to move the camera proportionally in the pitch and mix the left/right with the yaw input to turn the hexacopter left and right, giving me control over where the camera points. So I could fly to where I want to film, put the copter into pos hold and then the concentration shifts to the left hand to control where the camera points and the height the camera is off the ground.

  • Aluminium sheeting cut and welded into this shape and then placed on a fold out seat.  You then sit with it under you to stop it from moving.  I'll design some form of tension control on the collective stick so that it is not easily bumped.  Padded armrest on the right to elevate the arm to be in line with the hand-grip.

  • Perhaps something simple like this -


  • This is a cool example of a home made heli control simulator.  Collective on the left.

  • To simulate the collective on a full size heli.  Allows for a more accurate adjustment of throttle.  Won't have a twist grip to control throttle as you would for a real collective, just the up/down to control throttle.  Counterbalanced and probably have a small leaver to lock/unlock it's position.

    I will take a portable chair to the flying site which can have a support attached to the right to sit the joystick on and the collective control can bolt onto the left of the chair.  A shrouded LCD will sit in front of me either on a portable table or a tripod.

  • John, may I ask, what is a collective stick/control?

    Thank you.

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