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headtracking with oplink
« on: January 29, 2017, 03:00:44 pm »
Hi everyone! I'm still waiting for my oplink so i didn't try, but i'd like to try moving the camera gimbal with head movement using the ground oplink connected to pc as tx and as joystick a free headtracking platform as hatire arduino, smartphone with freepie and opentrack or similar. Is it possible to use more than one joystick at the same time( one to control vehicle and the other for camera)? Does the gsc recognise hatire arduino, vjoy virtual joystick, freepie, trinus or direct udp from smartphone IMU? Anyone tried something similar? Thank you and sorry for my english!
« Last Edit: January 29, 2017, 03:06:19 pm by andre.g »

Re: headtracking with oplink
« Reply #1 on: January 30, 2017, 11:03:54 pm »
Most gimbals have servo inputs so the gimbal stays level, but if you change the inputs you can change the angle the gimbal is at.

Are you trying to use the GCS to fly the copter?

GCS Options -> Controller shows setup for an 8 axis joystick (at least it does under Linux), but it only allows mapping the joystick axes to the normal flight functions, so I think it would require code changes.

Does your head tracker insert signals in the PPM stream or what?

I would advise skipping the GCS joystick.  If you want to use a computer joystick, there are plenty of projects that will give you a PPM stream from a joystick.  Google:
joystick PPM

Most RC transmitter output PPM from their trainer ports too, so you have a joystick and PPM converter all in one box with that.

Add to the PPM stream with the head tracker, feed the resultant PPM stream into an OpLink.  Using say a Revo in the copter, you could configure the head tracker signals to come out of the two unused servo-ESC outputs and connect those to the gimbal inputs.

It would probably be easier to just use a normal RC transmitter/receiver and something like this (first one I ran across):


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Re: headtracking with oplink
« Reply #2 on: January 31, 2017, 02:55:32 pm »
Thank you for the answer! Why do you suggest to skip the gsc joystick? Is there any lag if you control the aircraft from gsc? I don't have any specific headtracking device, i connect the smarphone with usb to pc and put the smartphone on my head , with some apps you can make a computer joystick and it works quite well.
An other idea was to connect a cheap IMU and joystick's potentiometers to arduino control board to send ppm to uart port and connect them to oplink or configure a joystick connecting to pc with usb  port and then using the gsc.
I have a revo so i'd like to take my laptop with me in any case.
As gimbal i wanted to make a simple servo gimbal and use the Revo directly.
Thank you again
« Last Edit: January 31, 2017, 03:51:30 pm by andre.g »

Re: headtracking with oplink
« Reply #3 on: January 31, 2017, 06:00:08 pm »
To use a joystick (for head tracking) you must either:
- modify GCS code
- buy some unknown devices to convert joystick into PPM stream which bypasses the GCS anyway.
So it is easier to start with a single device (head tracker like I linked)?

There are many unknown or never done hoops to jump through to get smartphone headtracker data inserted into an existing PPM stream.  For $35 plus shipping (maybe less) you can buy something that does what you want.

Now what would be interesting and useful is for someone to get CC3D working as a head tracker.  Basically turn a $8 CC3D into that $35 head tracker.