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FLIR Tau2 on P2 but with a twist... H3-2D/Tau2

Discussion in 'Phantom 2 Discussion' started by fxmodels, Sep 30, 2014.

  1. fxmodels

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    I have a project coming up where I need Infrared capability on a quadcopter so I obtained a Tau2-336 camera from FLIR Corporation to integrate into the Phantom airframe. I previously had an H3-2D gimbal on the Phantom2 but the harsh yaw issues during turns forced me to change over to the newer, better performing H3-3D for pristine cinematic footage.
    When I received the Tau2 my first thought was to make up a hard mount to the P2 and just go with that... But, I wanted stabilized camera footage for our purposes so I took that old H3-2D and converted it in two short hours to take the Tau2 and it performs AMAZINGLY. And now I want to share it with all of you.

    There are a number of issues with this camera on that gimbal. This is a short discussion of those problems and the ways that I overcame them. Let me know if you have questions.

    Problem 1:
    First, to say the least you have a front protruding lens on the Tau that will extend forward by an amount that depends on the focal length of the lens you are using. I am using the 9mm for a 37 degree field. That front loaded weight of course throws the weight on the gimbal so far forward that using the camera alone on there with no balancing methodology caused the motor to stall and drop the nose down.

    Problem 2:
    The second problem is that the back side of the camera has a ribbon cable connector that you can either connect to and parse out for USB or video out OR, attach a small little circuit board to the back in that connector that does the job for you, leaving you two outputs on the camera: USB and standard Video. I chose to use the little circuit board but doing so adds another wrinkle that is not insurmountable: the clearance between the video out connector and the H3-2D gimbal roll axis motor housing is small, at around .3" or so. That video out port is a tiny little MCX connector which is just a micro sized SMA type connector. So the clearance is tiny there. Next to that is a USB connector and luckily this has no impediment as it is to the port side of the roll axis (left side as viewed from behind) and is not a worry.

    Problem 3:
    The third problem is that the Tau2 camera requires 5 volts or so. I say "or so" because there is a tiny bit of flexibility to the input voltage at 4-6 volts.

    Problem 4:
    The fourth problem is that the Tau2 doesnt have a built in recorder. This aint no Gopro! So adding a DVR to the system was essential and if you want clean footage, you have to add it onboard and not take it off the video downlink which has the prospects of allowing video tearing, static, or other disruption to what should be pristine footage.

    Problem 5:
    There is a circuit board filling the whole back face of that camera mount on the gimbal! Any video out or USB out on the cam would have to go right through the board...

    And finally...

    Problem 6:
    Getting the camera attached to the mount!

    So with these problems at hand, here is how I fixed them one at a time.

    Problem 1: Balance...
    This was tricky. When the camera faces outward toward the horizon (lets call it zero degrees) it needs the most balance weight. But as it tilts progressively downward toward -90 it actually requires less weight when you examine the weight distribution and the resultant force on the motors. It needs the least of course when pointing straight down at -90 because this is the rest position. The motor is at its least stressed point. But how to make a variable weight distribution system that is easy, passive (requiring NO power) and effective at all speeds and attitudes? When I figured it out I laughed... It was far easier than I imagined and I tried a few things. I tried extending a weight straight back from the back side of the camera mount to counterbalance the forward weight. It is a logical thought to try that. But THAT causes the ROLL axis motor to fail because you cant put that rearward extending weight on the centerpoint of the roll axis since that axis is in the way. I tried just putting a weight onto the back side of the mount but there are clearance issues again with the video cable first and then any counterweight next... So the only way to get the weight aligned with the roll axis but still do the job on the tilt axis was to actually hang it on a moving little spar, hanging by gravity just behind the camera mount back plate and just in front of the roll axis motor housing. Even THAT is exceedingly close but the weight distribution balance works.

    Problem 2: Clearance for the Video connector...
    In this case the tiny MCX connector itself is actually too long just without any modification. Using a dremel I cut the back side sleeve off of the connectorleaving only the main barrel and of course the connector that gets buried in the camera. This along with very fine 24 gauge wire (unshielded) allows for the creation of a tiny 90 degree connector MCX style. I found the connector at Cables and Connectors in Berlin CT and they have a large online presence. You can order these in five minutes. I drove there this time and got it there. So the video connector clearance issue was solved.

    Problem 3: 5 volts of power...
    I found exactly 5 volts power on the motherboard on a connector marked "fan" but I do not yet know the current capacity of this port on the board. The Tau2 only uses around 200 milliamps or so to operate BUT... it has a mechanical shutter inside to block the sensor for what is called a Flat Field correction. Basically this removes accumulated noise on the sensor during operation. That shutter would use a lot more power to operate and it can go off every few seconds to every few minutes depending on how the camera settings are defined in the initial setup. The more it goes off the clearer your video will be overall. So I opted to go a different route with this. I dug through my drawers and found a little 12v power supply that steps down to 5 volts. Translation: A 12 volt plug for the lighter port on your car that goes out to USB... Used for charging and powering USB devices. I cracked open the housing and used that small circuit for now. It takes in 11.1 volts from the battery and outputs 5 volts. As teh main battery depletes, there is NO affect on the output of the camera because the camera remember can operate at 4-6 volts so when we go sub 5 volts on the camera power it still functions fine. I will eventually pick off 5v on the motherboard once I can figure out the max current capacity of that fan circuit. I bought a second motherboard for the P2 to have on hand if I blow up the one I have in the quad.

    Problem 4: DVr dVr DvR DVR
    I need an onboard DVR because the footage I want needs to be pristine. That said I chose the foxtech DVR circuit board that has a remote so I can turn on the DVR or turn it off without bringing the copter down. It works great and I used RC connectors everywhere so I can unplug it and put it before or after the iOSD for instance.

    Problem 5: circuit board relocation
    Yeah that annoying full circuit board with gyros in the mount needs to be abstracted from its current location which is smack dab where the video OUT and USB power IN need to go OUT... Get that? . So I cut out the back side of that plate after removing the circuit board and I literally just double stick taped it in the same exact orientation (black side out as seen from the front) to the back plate, but to the lower left of that back plate (port side rear) and sticking out slightly to the port or left side. You can see it in the pics... This works just fine. Actually it works surprisingly well.. the little ribbon cable needs to be unthreaded from around the tilt axis motor housing, the cover of which you can take off and leave off. The ribbon cable conforms to the motor housing anyway and once unthreaded from its strange wrapping you can simply plug it back in and tape it down to the back side of the camera mount plate. NO kidding. It works just fine.

    Problem 6: Attachment to the mount!
    Yes this is a big one. I dont have it attached yet in a 'prettier' manner but I used zip ties for now. I am currently building a simple mount plate that will allow the camera to sit in exactly the same way. Its coming. I will post that when done.

    ----------------

    This process took only a couple hours not including time to drive to Cables and Connectors to get the MCX plug. Note that the actual amount of weight used is critical. You cant have too much or the motors will stall and cease working until they reset in about 30 seconds. To little and the same problem happens. Try to mount the weight elsewhere on the back plate and the rotation motor will stall ... This is the best alignment and positioning.
    In this configuration as is, the motors do not stall at all even under power and during flight. The small lead weight and its spar do NOT swing madly under the camera because I am using wire wrap wire to hold it to the camera mount back plate which will dampen the swinging substantially but it MUST be free to move as the gimbal tilts. Once in place its a set and forget issue. Suffice it to say that the H3-2D gimbal is working great. I have flown the cam ten times or more so far and the mount works fine with no camera axis drop from the motor stalling issue. Plus, since the Tau2 weighs LESS than a goPro, adding back a little weight doesnt affect my run times. In fact I get the same run time for all this including the additional DVR and power supply for the camera and the weight of each.

    Pics:
    [​IMG]
    Pic1: Setup without permanent camera mount. Note the circuit board with gyros abstracted out of the gimbal and protruding on the lower right. This has NO effect on stabilization.

    [​IMG]
    Pic2: The counterweight setup. Note that it hangs low enough so that at full -90 degree tilt neither the weight nor its spar on which it is attached interferes with the mount. The clearance is perhaps 1mm in that position!

    [​IMG]
    Pic3: Orientation of the circuit board that used to be inside the camera. This works very well...


    NOTE: There is one pic that shows flat LEDs on a strip mounted above the camera on the front face of the P2. Those are for another project element and not IR LEDs or part of the IR thing ...

    Let me know if you have questions..
    Thanks,
    Marc Dantonio

    FX Models/Trumbull Studios
     
  2. macheung

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    Congrates and thanks for sharing.
    I would love to do this except the cost of the FLIR is just too much.
    I wish someone would just make a general purpose gimble that can accept a wide range of loading. That way, you just strap on whatever camera and off it goes.
     
  3. TeamYankee

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    Are you able to post some video of the FLIR in action, that would be cool?!
     
  4. Rdmn74@hotmail

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    So I'm doing the exact project with the TAU 336. Can you post more pics of the counter weight. Also I'm looking to be able to switch back to the GoPro relatively fast, any ideas on making this a quick disconnect setup?
     
  5. AVC

    AVC

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    Very awesome! Any chance you could post the last update and a few more pictures?
    Thanks and again, great work!
     
  6. TeamYankee

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    they have.. the DYS gimbal... has it's own gimbal controller and a huge amount of parameters you can change to adjust the loading.