Review: Kakute F7 Flight Controller

Spoiler: the Kakute F7 AIO flight controller is pretty sweet! With Betaflight performance of F7 FC’s continues to improve, it’s safe to say that F4 is no longer the only option when it comes to choosing your next FC!

Check out our Flight Controller Buyer’s guide.

Where To Buy?

All-In-One Version (PDB integrated)

You can get it with the Atlatl V2 VTX as a combo to save a few bucks :)

Non-AIO Version (Best with 4in1 ESC):

Spec

  • Target: KTF7 (Kakute F7)
  • MCU (Processor): STM32F745
  • Soft-mounted IMU (Gyro): ICM20689
  • Input Voltage: 2S-6S
  • BEC: 5V/2A, 3.3V/0.2A
  • 6 UART’s
  • 6 motor outputs allows for hexacopter configuration
  • Built-in Current Sensor (up to 130A)
  • Onboard BMP280 Baro Sensor
  • Micro SD card slot for blackbox recording
  • Support Betaflight OSD
  • Dimension: 35x48x7mm
  • Weight: 11g

Advantages of F7

No Inversion Required!

When I was soldering the board, I couldn’t find any info about SBUS and Smartport pads… Then I remember this is an F7, it doesn’t care about inverted signals!

You can Just connect SBUS and Smartport to any UART and it just works! Having used F4 for so long, I forgot how easy F3 and F7 is!

Low CPU load

F7 is a more capable processor than F3 and F4. With continuous optimization in Betaflight firmware, it will only get better. As for right now (BF3.4), here is the CPU usage running different gyro sampling rate and looptime. (With Dynamic filter, Airmode, Anti-Gravity enabled, ACC disabled)

  • 8K/8K – 2% CPU load
  • 16K/16K – 7% CPU load
  • 32K/16K – 19% CPU load
  • 32K/32K – 54% CPU load

Closer Look at the Kakute F7 AIO FC

The Gyro is soft mounted, connected to the board with a flexible ribbon cable. The height of the FC including the Gyro is about 7mm.

The metal bar on the top is connected to the LiPo positive, so make sure you don’t accidentally short it :)

No ESC signal ground on this FC, but there are dedicated ESC telemetry pads at each corner.

Just like other Kakute boards, the Kakute F7 doesn’t support PPM and PWM receivers. If you insist on using these receivers, you can get a PPM to SBUS converter, or PWM to SBUS converter for this board.

I like the Kakute FC series, but the long shape is not going to fit in certain frames. For most  freestyle frames it shouldn’t be a problem.

Here is the pin-out (wiring) diagram.

There are 6 UART’s, more than enough for a racing drone, even long range GPS platform.

There are also an onboard BMP280 Barometer and i2c port for GPS module, which are great for GPS applications like iNav.

After using the Rotor Riot Control FC, I really like having the soft mounted gyro protected inside a plastic case. You don’t have to worry about running wires on top which might touch the gyro. I think Holybro should consider something like this.

Kakute F7 Non-AIO FC

The spec and features are the same as the All-in-One version, except it doesn’t have the large solder pads for power and ESC’s, and the layout is slightly different.

The Kakute F7 board doesn’t have breakout soldering pads for ESC signals, so you would have to use the JST connectors to connect to the ESC’s.

Watch out for the non-square shape and the “extended tab” as it might not fit certain frames with tight spaces.

In my opinion this FC should be used with an 4in1 ESC, for example the Tekko32 4in1.

It can be bought together with the Atlatl HV V2 VTX as a bundle.

The pin-out is similar to the AIO version:

Hardware Bug

There is a hardware design flaw in this FC. For me, motor 3 and 4 didn’t work with DShot out of the box. Though all the motors outputs worked with Multishot (don’t forget to calibrate the ESC’s). Multiple users reported the same issue.

There is a work around though. If you don’t want to run Multishot, just DShot, you can simply disable camera control in CLI.

resource CAMERA_CONTROL 1 none
save

You can still use one of the spare motor outputs (5 or 6) for camera control if you want. There is a 220 ohm resistor connected to these pads already so you might not need extra resistors. To do so you can enter the following commands in CLI:

resource MOTOR 5 none
resource CAMERA_CONTROL C09
set camera_control_key_delay = 125
save

Holybro announced that they will disable camera control feature on all the Kakute F7 boards from now on to support DShot. This bug is only likely to be fixed after Betaflight 3.4.0.

Flight Videos and Follow Up

Despite the hardware bug (not a problem at all if you don’t use camera control), I still like it more than the Kakute F4 – it has more UART’s, no need for signal inversion hacks, and it has 6 motor outputs.

I have been flying this board in my Flipmode frame for a few days now, it’s been solid!

ArduPilot Support

You can flash Ardupilot firmware on this flight controller for better GPS features.

Edit History

  • July 2018 – Article created for Kakute F7 AIO
  • Sept 2018 – Added info about the non-AIO FC

24 thoughts on “Review: Kakute F7 Flight Controller

  1. Travis

    The manual I have says to use M5 for analogue camera control (im using a predator v3), but you seem to have used the CAM pin, which way is correct?

    Reply
  2. BlackHawk

    Does anyone know what the ‘I” pin is on the F7 plug? I’m wondering if it the current pin to the 4in1. Any help would be great.
    Thanks.

    Reply
      1. BlackHawk

        I am wiring the F7 to Aikon32 4 in 1 ESC and i’ve matched the current pin on the ESC to the “I” pin on the F7 but i’m not getting any current. I do have the port and the ESC setting turn on in betaflight. Any thoughts on why I’m not getting current?

      2. Oscar Post author

        The pin “I” is not part of the ESC telemetry, it’s just a current sensor reading. You need to select “Onboard ADC” in power setting tab in Betaflight for current sensor.

  3. Mike

    Suggest a WARNING be provided in your post that ‘reversing an ARDUPILOT’ flash is difficult and your Kakute F7 may not easily go into DFU mode. Thanks for the post. Very informative. BUT ….. do you have any idea how to flash from Ardupilot back to Betaflight on the Kakute F7?

    Reply
  4. Chris

    This FC works with ArduPilot. I think it is one of the lowest cost flight controllers you can get for a photography drone.

    It would be good to see his FC reviewed by someone who is going to load this up with sensors and gear and use all 6 UARTS. How well does GPS position and altitude hold work?

    My guess is that for racing you are not going to notice the difference between this and an F4 or F3.

    Reply
  5. Mark

    What magical Fairy Dust does the Kakute F7 AIO require to actually get the GPS to be recognized by BetaFlight?
    I have tried multiple UART connections, reversing the RX/TX on each, and separate M8N GPS/Compass units.

    Same results…
    I have gone off and ordered a Pixhack V3 just because tired of dicking with poorly document boards like this.

    Any ideas – Been through every Betaflight manual and video I can find.

    Reply
    1. Jonathan

      For me GPS was recognised straightaway, once I’d changed protocol to ublox.
      A few pointers for anyone with a problem: –
      Make sure you cross rx/tx over
      Only works with a battery connected, not on USB power
      Change protocol to ublox

      Reply
  6. Mike Cahill

    I am also unable to run at 32/32 without pegging the CPU at 100%. I can get to about 30% CPU running 32/16 with ACC and barometer off. Have tried re-flashing and erasing all settings, turning off all sensors but it just pegs at 100% at 32/32 no matter what. Weird. Will email holybro.

    Reply
    1. John P

      I’ve just installed a kakute F7 and have the same on BF 3.5.1 32/16 = 34% cpu usage, 32/32 = 100% disappointing was hoping to finally try this and expected it to run it with plenty of head room.

      Reply
  7. Juan

    I bought the Kakute F7 and cant seem to run 32/32k with Dshot 1200.
    If I try without overclocking, my CPU load goes straight to 100% with the same settings you are running.
    Did you overclock the CPU to 240MHZ to achive 54% at 32/32k?

    Reply
    1. Oscar Post author

      No I didn’t overclock it. Even at 54% CPU load, it’s still a bit too high, maybe stay at 16K for now until they optimize it a bit more :)

      Reply
  8. Niklas

    I bought the Kakute F7 and cant seem to run 32/32k with Dshot 1200.
    If I try without overclocking, my CPU load goes straight to 100% with the same settings you are running.
    Did you overclock the CPU to 240MHZ to achive 54% at 32/32k?

    Reply
    1. Matthew Earle

      ON my FPVmodel F7 i had to disable blackbox logging completely. Then it went down to 41% overclocked at 32/32k. AC and other sensors disabled as well. I think i also had to turn on Dshot burst as well. That helps with CPU but not sure if its supported on all flight controllers.

      Reply
  9. Dmitry

    It’s interesting how flight controllers are picking up more and more powerful processors. I guess, H7 FCs will come soon as well.

    Reply

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