FoneTroll II: Gyro-mounted FPV/controller

Static-orientation screen holder with dynamic gyro-based controls for RC vehicles

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Phone mount that holds your display (phone, tablet, monitor) steady as an FPV display while offering 2 degrees-of-freedom kinematic controls that do not affect display orientation.

Next-level multicopter/robot controller designed to more fully emulate hands-on control of a remote driving or object manipulation experience while keeping the display at a consistent orientation regardless of controller orientation.

The dimensions in which the controller can move include:

Rotational (clockwise/counter clockwise) like a steering wheel

Pitch (forward/backward)

These dimensional changes are registered with the onboard gyro of the gimbal controller. If this gyro is not present, a cheap setup with the MPU6050 and an arduino nano provides the signal that controls the game/vehicle. Phone orientation is also registered in the same way. The phone is gimballed to the hub from which the grips extend.

Additionally, on each grip, a small thumb slider and at least one button allow for further control of target (robot/drone/game).

Grip structure relays positional info and other input to a microprocessor while the phone gimbal has its own processing board.

Both of these independent systems are powered by lipo battery.

  • Mounting the screen/phone to the gimbal

    ken.do06/01/2018 at 21:56 0 comments

    Most gimbals are equipped to handle a gopro style camera, meaning the support 'tray' is oriented horizontally for the camera to sit on. Our phone or display will not be sitting on it. Reorienting the tray to act as a back plate-style mounting surface shoud be easy enough: just turn it...

    However, there is an MPU attached to this plate which sends the orientation to the processing board. To get this to register correct orientation, we will have to turn it 90 degrees so when the back plate is in the upright position, the MPU sits perpendicular to the display plane.

    To attach the MPU, one could 3D print an appropriate bracket, but since I have committed myself to a 'no-3D-print' build on this one, a flattened and right-angled piece of PVC screwed to the back plate and some hot glue will do just fine!

    There are a variety of kits for mounting almost any small screen to the back plate and this will have to mounted after a final screen is selected for this project. Mounting can be bolts, straps or my personal favorite, zip ties!

  • How to send control signals

    ken.do05/18/2018 at 02:43 0 comments

    So the screen is steady while you are moving the control grips around; supercool, awesome, great, but how does this control your remote project?

    My initial idea was to build an MPU into the grips and use that data to generate some sort of PWM signal (through an Arduino) that could be used by the remote project's onboard controller (in my case a CC3D Revolution flight controller) sent via an OPLink master. Then it dawned on me... The control signals sent from the gimbal board to the ESCs that control the gimbal motors are PWM, why not grab that signal and feed it into the OPLink? How the output from OPLink slave is interpreted by the flight controller may need some adjusting in the setup program (LibrePilot in my case) but it just might work...

    That leaves only yaw control to worry about. A thumbslider joystick hooked up to an ATtiny for conversion to PWM and then sent along to the OPLink Tx should do the trick. This slider can be placed on one of the grips.

  • Gimbal

    ken.do05/10/2018 at 19:04 1 comment

    Having looked at hundreds of gimbals, I am going for cheap, light and simple. Essentially all versions of this are all very similar.

    To attach it, I will flatten a section of PVC pipe ( the piece that goes between the grips) drill and bolt in place.

    The gyro unit that resides on the camera base may need to be re-oriented so that the phone/tablet can be attached to the (former) bottom of the gimbal frame. Pics will follow...

  • Off the shelf

    ken.do04/30/2018 at 22:39 0 comments

    For my proto, I am planning to go as 'off the shelf' as possible. A lot of my other designs have a lot of 3D printed parts, but this frame is going PVC...


    1 inch PVC pipe is awesome. Just, awesome. Things I have built with it include:

    - hammock

    - greenhouse

    - fan stand

    - hot-wire foam cutter

    - and i have actually used it to carry water (weird, I know)


    Rather than try to build my own gimbal and gimbal controller, I am opting for a pre-made consumer gimbal (boo, hiss, DIY faux pas...) It comes with motors for under 60$CAD.


    Custom building lipos from separate cells is retarded. And zappy-smokey sometimes. Oops. OTS please. 3s 1300mah should be plenty for hours of entertainment.


    Arduino Nano cause I have a pile of them. Proto will be hardwired to a Tx for control. Bluetooth/WiFi may be added later via Pi Zero W. Softwares will be fairly stock too.


    I know, I know... iPhone? Am I serious? Maybe. Mostly it is an easily found model... Not for me personally, but to each their own.

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