FPV setup for IRIS

Unfortunately 3DR does not offer a dedicated FPV kit for IRIS and the FPV kits available from 3rd parties do not include an On-Screen-Display (OSD). Therefore here the instruction on how to assemble your own FPV kit – no soldering required.

Addressed design Requirements

But before we get started, let’s go over some design requirements. These are the requirements that I wanted to fulfill with my IRIS FPV setup:

  • Weight: The setup – especially the transmitter – should be small and lightweight as IRIS is already under-powered as is.
  • Power-Source: The setup should use the main battery as power source, as adding another battery would increase the weight of IRIS even more.
  • OSD: The setup should include an OSD (On-Screen-Display) module for receiving flight data, while in flight. It is almost impossible to judge your altitude or speed from looking solely at the video feed. Having such critical information displayed right in front of you helps a lot. Even though you can use an Android enabled tablet to receive flight data, having redundancy of these information improves flight safety. Also when using goggles as the ground segment of your FPV setup, having important flight information directly displayed in front of your eyes is crucial.
  • Camera: The setup will use the GoPro camera attached to the Gimbal or mounted on the front as the camera. An additional camera would yet again add weight to IRIS. (While the usage of a GoPro as FPV camera is discussed controversially in various forums, I haven’t had any issues in 100+ flights with the GoPro locking up or freezing, other than user error. See below for more.)
  • Accessibility: It should be possible to access the Transmitter in order to change channels without having to open the top hull.
  • 5.8GHz channels: The setup should work with all available channels in the 5.8 GHz band and not just the F band used by Fatshark.
    In addition the setup will only include the air part. You are free to use whatever ground part you like. Both goggles or screen will work just fine.
  • Soldering: No soldering required: Myself I’m neither willing nor capable to solder anything on IRIS. Therefore I wanted an FPV solution that does not require soldering. If you are willing and capable to solder, you can e.g. solder the power cables together instead of using the JST Plug 1 Female to 2 Male Expansion Adapter below.
  • Turn On/Off: The user should be able to decide before each flight whether to use the FPV setup or not. When e.g. flying an auto mapping mission with the GoPro setup for taking pictures, the FPV can be safely disabled.
  • Battery voltage: The setup should work with both 3S and 4S batteries.
  • Power GoPro Camera: (Optional) It should be possible to power the GoPro from the IRIS main battery. The reason for doing so is the following: The GoPro camera will stop video output via the USB-like port after a few minutes, unless it is powered or recording. Therefore in case you fly FPV with a GoPro camera and without external power and forget to hit the record button, you might suddenly get a black screen mid flight. Believe me, not a great situation. Been there, done that.

With these goals in mind, let’s get started

Required materials and tools

You will need the following materials:

If you want to power the GoPro camera from the main flight battery of IRIS you will also need these materials:

The following tools are required:

Warnings!

Please read these important warnings carefully!

  • Never power on the Boscam FPV Transmitter without an 5.8 GHz antenna attached to it! It will permanently damage your FPV Transmitter.
  • The use and operation of FPV transmitter in the USA and many other countries may require a license and some countries may forbid its use entirely. In the USA, you will need a “HAM” amateur radio license. It is your responsibility to ensure that the use of these instructions and product meets the requirements imposed by your government’s rules and regulations for RF devices!

How-to assemble

Let’s get started assembling our FPV setup.

Step 1: Changing connectors

First we will need to change a few connectors on the cables:

  • On the cable that comes with the Boscam 5.8GHz 32CH A/V 500mW Transmitter, cut off the USB adapter as close to the adapter as possible (See Figure 1).

    Figure 1: Remove the USB adapter

    Figure 1: Remove the USB adapter

  • Use the Pin Crimping Tool and place JWT connectors (1 pin) onto each of the two wires. We will later use these two connectors to connect to the Video Out/Ground of the OSD module (See Figure 2).

    Figure 2: OSD module connected to FPV TX

    Figure 2: OSD module connected to FPV TX

  • Next, on the FatShark Filtered Balance Lead Power Supply cut off one of the molex plugs (See Figure 3).

    Figure 3: Fatshark Cable with connector to be replace

    Figure 3: Fatshark Cable with connector to be replace

  • Use the Pin Crimping Tool and replace it with a JST Male 2 pin connector (See Figure 4). Pay attention to the polarity (red and black wire)! Refer to the picture below for correct polarity.

    Figure 4: JST Male connector

    Figure 4: JST Male connector

If you want to power your GoPro via the main flight battery, you also need to change the following cables:

  •  On the open end of the 5V / 3A Switching UBEC install a JST Female 2 pin connector (See Figure 5). Pay attention to the polarity (red and black wire)! Refer to the picture below for correct polarity.
    Figure 5: JST Female connector

    Figure 5: JST Female connector

     

Step 2: Install the components

Next, let’s install the needed components. We will start with the FPV transmitter.

Use a small strip of 3M Dual Lock on the back of the FPV transmitter – the side that does not include the switches for the channels and the connector. Use the corresponding 3M Dual Lock strip on the bottom of the lower IRIS shell, between Gimbal and battery door (See Figure 6). Carefully cut free the connector and channel switches through the plastic wrap of the FPV transmitter.

Figure 6: FPV transmitter mounted with 3M Dual Lock

Figure 6: FPV transmitter mounted with 3M Dual Lock

Point the connector of the FPV transmitter towards the Gimbal. Attach the air side of the IBCrazy 5.8 GHz Bluebeam Ultra Antenna via the included angled adapter to the FPV transmitter. The antenna should point downwards for optimum transmission.

Use some more 3M Dual Lock to attach the OSD module, LC Common Mode Power Filter and optional 3A Switching UBEC to the top plate, underneath the top hull. Place all these components right in front of the Pixhawk, while ensuring that they do not touch the Pixhawk (See Figure 7).

Figure 7: FPV components mounted on top plate

Figure 7: FPV components mounted on top plate

Point the analog side (field with 3×2 connectors) towards the right middle. That’s where will later route the cables to.

Step 3: Routing the cables

Route the Tarot Gimbal GoPro Video Cable in parallel to the existing Tarot Gimbal control cable. You will need to temporarily remove the lower shell for this. Make sure that any excess length of the cable is towards the Gimbal. Plug the USB end of the cable into the GoPro camera (See Figure 8). Ensure that the Gimbal can still freely move and that you can tilt the camera without any problems.

Figure 8: Cable connected to GoPro USB port

Figure 8: Cable connected to GoPro USB port

Connect the Tarot Gimbal GoPro Video Cable to the OSD module. Use the plug, where the wires run to the outer connectors and the middle connector is unused (See Figure 9). The opening of the connector with the metal pins has to face upwards onto the top 3×1 row of the 3×2 connector field.

Figure 9: Connect Tarot Gimbal GoPro Video Cable to OSD module

Figure 9: Connect Tarot Gimbal GoPro Video Cable to OSD module

Next connect the FPV Transmitter cable – the one where we replace the USB plug with a JWT connector – to the OSD module (See Figure 10). The cable with the white line on it will need to connect to the Video Out pin on the 3×2 field and the black cable will need to connect to the Ground pin on the 3×2 field. Route this cable along the two Gimbal cables towards the FPV transmitter on the bottom of IRIS.

Figure 10: OSD module connected to FPV TX

Figure 10: OSD module connected to FPV TX

If you are using the 3A Switching UBEC, connect the Servo Extension Cable to the remaining connector of the Tarot Gimbal GoPro Video Cable. You should notice that the black and red wires of the Servo Extension Cable match up to the two black cables of the Tarot Gimbal GoPro Video Cable, the white wire is not used.

Plug the other end of the Servo Extension Cable into the back of the Pixhawk. Use the port “Main Out #8”, with the black wire on the top pin and the white wire on the bottom pin (See Figure 11).

Figure 10: Powering the Pixhawk via the 5V UBEC

Figure 10: Powering the Pixhawk via the 5V UBEC

Connect the Output of the 5V / 3A UBEC to port “Main Out #5, with the black wire on the top pin and the red wired on the middle pin.
This will power the Pixhawk via the 5V / 3A UBEC in addition to the previous power source. It will also provide the power for the GoPro via the Servo Extension Cable.

Next place the FatShark Filtered Balance Lead Power Supply into the back of the battery bay and route the cable between the lower tray and the lower shell towards the right side of IRIS and up to the upper shell (See Figure 11).

Figure 11: FatShark Filtered Balance Lead Power Supply

Figure 11: FatShark Filtered Balance Lead Power Supply

With the MinimOSD cable for Pixhawk connect the port “Telem2” on the Pixhawk to the OSD module. The metal pins on the plug of the OSD module site have to face downwards (See Figure 12).

Figure 11: MinimOSD cable for Pixhawk

Figure 11: MinimOSD cable for Pixhawk

Step 4: Add power cables for the components

This steps depends on whether you want to power the GoPro camera with the 5V / 3A UBEC or not.

Let’s start with the case that you don’t: In this case, connect the FatShark Filtered Balance Lead to the LC Common Mode Power Filter. From the LC Common Mode Power Filter connect directly to the Boscam 5.8 GHz FPV transmitter (See Figure 12).

Figure 12: Power setup without 5V / 3A UBEC

Figure 12: Power setup without 5V / 3A UBEC

In case you do want to use a 5V / 3A UBEC: Connect the FatShark Filtered Balance Lead to the JST Plug 1 Female to 2 Male Expansion Adapter. From one output of the expansion adapter connect to the LC Common Mode Power Filter. From the LC Common Mode Power Filter connect directly to the Boscam 5.8 GHz FPV transmitter. From the other output of the expansion adapter connect to the 5V / 3A UBEC (See Figure 13).

Figure 13: Power setup with 5V / 3A UBEC

Figure 13: Power setup with 5V / 3A UBEC

Step 5: Configuring the Pixhawk

Before you can use the OSD module, the Pixhawk has to be configured for transmitting Telemetry data to the OSD module. Use Mission Planner to change the following ArduCopter parameters.

This is the complete list with the respective values:

  • SERIAL2_BAUD, 57 (telemetry output at 57600)
  • SR2_EXT_STAT, 2 ( 2hz for waypoints, GPS raw, fence data, current waypoint, etc)
  • SR2_EXTRA1, 5 ( 5hz for attitude and simulation state)
  • SR2_EXTRA2, 2 ( 2hz for VFR_Hud data )
  • SR2_EXTRA3, 3 ( 3hz for AHRS, Hardware Status, Wind )
  • SR2_POSITION, 2 ( 2hz for location data )
  • SR2_RAW_SENS, 2 ( 2hz for raw imu sensor data )
  • SR2_RC_CHAN, 5 ( 5hz for radio input or radio output data )
  • BRD_SER2_RTSCTS, 0 ( Disable Request to Send / Clear to Send )

Step 6: Using your FPV setup

When you are ready to use your FPV setup with IRIS, follow this sequence to power up IRIS and the FPV equipment:

  1. Power up your FPV receiver, e.g. FatShark goggles or the excellent FlySight screen with build-in receiver.
    Don’t forget to check out my FPV ground station setup.
  2. Power up your GoPro camera.
  3. Connect the main battery lead to IRIS. This will power up IRIS the same ways as before. It will not power the FPV transmitter though.
  4. Connect the balance lead of the battery to the FatShark Filtered Balanced Lead. Within a few seconds you should see the output of the GoPro camera and the OSD module booting.
    Sometimes the OSD module becomes stuck in the boot process and you will not see any Telemetry data. In that case, disconnect both balance lead and main lead and start again from Step #2.

During flights you should see update telemetry information overlayed by the OSD module on top of your GoPro video (See Figure 14).

Figure 14: Example of FPV output

Figure 14: Example of FPV output

After a flight, disconnect both the main battery lead as well as the balance lead. This is especially important for the case that you use the 5V / 3A UBEC. With this setup the Pixhawk will be powered by this UBEC for the case that the main power source via the main battery lead fails. As a result it will initiate a battery failsafe after 5 secs, as it detects the voltage to be 0V.

Configuring your OSD

You can configure the layout of the OSD screen, in order to declutter it and only display the information important to you. For this you will need the OSD Config Tool as well as the FTDI Cable 3.3V.

Use the same cable and software to update the MinimOSD software and charset.

Downloading media from the GoPro

In a previous post, I already provided a solution for connecting to the GoPro USB port without removing the camera from the Gimbal. Unfortunately this approach won’t work anymore, as the Tarot Gimbal GoPro Video Cable cannot connect via the Motorola Right Angle Charger Adapter. The solution is to carefully cut off the black rubber casing around the Motorola Right Angle Charger adapter.

This will allow you to unplug the Tarot Gimbal GoPro Video Cable and plug in the Motorola Right Angle Charger adapter, while the GoPro remains in the Gimbal (See Figure 15).

Figure 15: Angled Mini-USB adapter with removed rubber casing

Figure 15: Angled Mini-USB adapter with removed rubber casing

Final Setup

The final setup from the outside is visible in Figure 16.

Figure 16: Final FPV setup

Figure 16: Final FPV setup

Flight time reduction due to the FPV setup is marginal. Range of the setup exceeds by far the R/C range of IRIS.

Alternatives

The presented FPV solution does provide a lot of options for alternatives. In case your design requirements differ from the ones listed above, feel free to alterrate the setup accordingly. Here are some ideas:

Updates for IRIS+

IRIS+ already uses the Telem2 port on the Pixhawk for providing telemetry data via the R/C transmitter. This port is configured for the FrSky Telemetry protocol, which is different from the Mavlink protocol used for the MimimOSD or the 3DR Telemetry radio. Therefore a special Y cable – similar to this Telemetry/OSD Y-cable adapter cable for APM 2.6 and 3DR Radio V2 – has to be made for the Pixhawk. This cable will need to connect the Telem1 port with both the 3DR Telemetry radio and the MimimOSD. Such a cable does not exists as a readymade option today.
An alternative would be to not use the Telem2 for the R/C transmitter telemetry and use the above instructions. reconfiguring it for Mavlink usage with MinimOSD. In this case you will not have telemetry data on the R/C transmitter.

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12 comments on “FPV setup for IRIS
  1. John O'Shaughnessy says:

    This is a fantastic guide! [ A shame I bought the 3DR kit a few weeks ago — it’s still on my shelf as I haven’t had time to install it yet]. Regardless, I will definitely use your guide for device placement, etc.

  2. John O'Shaughnessy says:

    In the alternatives section you mention 3S lipos twice. Should that first mention be 4S?

  3. John O'Shaughnessy says:

    After installing the FPV components, I assume there is a small change to the center of gravity. Did you/should you perform any recalibrations to account for the differences?

    • The added FPV components are very lightweight and are placed close to the center of gravity. With that, there is no need to perform any recalibrations to account for the differences.

  4. Mike says:

    All components ordered. Looking forward to trying this setup out on new Iris+ w/ GoPro 4.

  5. Mike says:

    Christian, I started a new discussion over on DIYdrones with a question around some alternative cables; http://diydrones.com/forum/topics/iris-fpv-setup-for-gopro-4?xg_source=activity

    Just thought it might get some more replies over there.

  6. Ashutosh says:

    I might be missing it but what is the display screen you’ve selected for this? I did not see it in the parts list.

    • Christian Elsen says:

      I’m using a FlySight screen with build-in receiver. It’s listed under section 6 above. I can highly recommend that one.
      I didn’t include it in the parts list as I wanted to keep the ground part separate. Some folks might already have a ground station, using it with another quad or prefer goggles over a screen, or vice versa.

  7. Chet says:

    Great guide…it helped me quite a lot.

    I have one clarifying question. I’m using the stock 3S lipos provided by 3DR for my IRIS+.

    Am I correct in assuming that I don’t have to mix with the Pixhawk if I don’t want OSD on my FPV? All I am trying to do is power the GoPro from the 3S lipo which means that all I really need is the UBEC and cabling from the alternative section?

    Thanks in advance!

    • Christian Elsen says:

      Yes, that’s correct. If you don’t want OSD functionality, connect the standard 3S Lipo via the uBEC to the Pixhawk and then the Pixhawk to the GoPro via the cable.
      This way you are supplying the Pixhawk with another power source for emergencies (issue with the primary power source).

  8. Cheddar says:

    I can not seem to find the parameter
    ” BRD_SER2_RTSCTS, 0 ( Disable Request to Send / Clear to Send )”

    the only BRD para that I see is “BRD_PWM_COUNT”

    am I missing something