Home Forums Everything about everything else Kakute F4 as the next FC on the RCExplorer store?

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  • #59222

    We are thinking of starting to carry an F4 board. I’ve heard good things about the Kakute F4 V2. It seems to be a good compromise between price and performance/features.
    Kakute F4 V2
    Are there any reasons not to use this board?

    #59223
    Kevin_Erik
    Moderator

    @David

    Looks good, just curious to know if there a dRonin target for it?

    Good video in the subject for those who have never used it.

    Manual
    http://www.holybro.com/manual/HolybroKakuteF4V2Manual_v1.1.pdf

    #59227
    LitterBug
    Participant

    Hi @david,
    At a quick glance, it seems very limited on PWM outs with only 4. Depending on the resource mapping, that could be problematic. http://www.holybro.com/manual/HolybroKakuteF4V2Manual_v1.1.pdf

    LitterBug

    #59230

    Agreed that fewer pads = not as good. But I think we can get around that somewhat.We should be good with running 2 servos + and 2 ESC’s as they use 2 different timers. Was thinking servo on either/both S2 and S3

    Here are the resource mappings in betaflight:
    DEF_TIM(TIM8, CH2, PC7, TIM_USE_PPM, 0, 0), // PPM IN
    DEF_TIM(TIM3, CH3, PB0, TIM_USE_MOTOR, 0, 0), // S1_OUT – DMA1_ST7
    DEF_TIM(TIM3, CH4, PB1, TIM_USE_MOTOR, 0, 0), // S2_OUT – DMA1_ST2
    DEF_TIM(TIM2, CH4, PA3, TIM_USE_MOTOR, 0, 1), // S3_OUT – DMA1_ST6
    DEF_TIM(TIM2, CH3, PA2, TIM_USE_MOTOR, 0, 0), // S4_OUT – DMA1_ST1
    DEF_TIM(TIM8, CH3, PC8, TIM_USE_LED, 0, 0), // LED_STRIP – DMA2_ST2

    #define VBAT_ADC_PIN PC3
    #define CURRENT_METER_ADC_PIN PC2
    #define RSSI_ADC_PIN PC1

    There is already an RSSI pad for one feedback wire and according to the datasheet of the STM32F405RG processor almost any pin should be possible to use as an ADC. So we could pick and choose a bit for the second feedback.
    For instance the led_strip pin we could easily steal if needed. Or one of the UART pins (the RX pin for the UART meant for telemetry)

    dRonin doesn’t seem to support many boards that are of interest: https://github.com/d-ronin/dRonin/wiki/Choosing-a-flight-controller-for-dRonin

    #59231
    Kevin_Erik
    Moderator

    The Bardwell F4 from what i hear is also pretty good.

    Matek works and has some dam nice features. However both of mine have some weird drift issue that I’ve not been able to nail down.

    #59238

    Yeah I’ve been considering the Bardwell board as well.

    I’m not thrilled with the Matek quality control otherwise it seems like an OK board.

    I would love to get @jihlein and @Terje input here as well 🙂 Hope they see this

    #59239
    Kevin_Erik
    Moderator

    @David

    The dRonin support page needs some updating for the Matek F405 and possibly one other FC. Maybe jihlein can fill in what’s missing next time he pop’s in.

    I will say this though, Flying my Baby-Tri has never been smoother than with dRonin. This was something I was never able to manage with Tri / Beta flight.

    #59240
    BLeeK
    Participant

    I like how the Kakuta boards have their gyro, except the ribbon can’t be extended which would would make possible mounting Gyro remotely to board to achieve perfect COG mass-point “null”, or near to it like current F3 TriFC, yet also allow mounting the FC itself in a slightly more convenient position…..

    I do like the Matek boards, but pretty much due to their PDB- the Matek Wing PDB would be near perfect…

    As to having enough PWM outputs, I kinda feel all the F4’s are a bit lacking & another good reason to ‘future-proof’ by going straight to F7- iNav did something & now runs much better on F7 than previous to version 2.0 & Ive heard Betaflight did something to improve running on F7 as well…

    Random thoughts Ive had on tricopters & bits & thought here & now might be a good place to share ’em…
    Thanks for the work you guys are doing, still working towards an RCE Mini-Tri of my own one day… 😀

    #59241
    LitterBug
    Participant

    I pinged one of the lead dRonin devs. Currently no support for the icm20689, but he seemed to think it might be an easy add if it is much like other InvenSense MCUs. Would still need to build an official target for it too, Time/difficulty would depend on mappings.

    I’ve also forwarded the link to this thread to @jihlein in case he hasn’t seen it. Currently dRonin support for the F3FC and Matek F450-CTR are by unofficial targets he has created.

    Cheers!
    LitterBug

    #59243
    jihlein
    Participant

    The ICM20689 datasheet, at first glance, reads very similar to the ICM 20608, MPU6000, etc. The drivers for that family are very common, and likely to work, with maybe the addition of a new device type code. So I don’t think that’s a big deal.

    As far as the Kakute board itself, I don’t know much about it. It does seem somewhat restrictive, not a lot of extra pins to re-purpose. From looking at the STM32F405 datasheet, the LED strip pin can’t be re-purposed as an ADC for a second fdbk input for example, nor can the UART1 RX pin. But honestly I’m still head scratching about the need for servo position fdbks on the bicopter at the moment. I do believe there’s enough info about the board to create a dRonin target for it if desired though.

    The existing RCE F3Fc is somewhat easy to solder given the relatively large sized pads and heavy copper. While the copper might be robust on the Kakute, the thru hole soldering will make it more difficult to move the board around to different/new installations over time.

    I don’t know how important support for dRonin is. There is no official support in dRonin for triflight, F3Fc, or the Matek405Ctr, I maintain a personal branch with those features. dRonin also does not have support for sd cards, soft serial, or some of the camera control features. Somewhat purposely, it does not support the “board of the month” to make project maintenance easier. But it offers (imho) better flight performance and an autotune feature that makes setup easier. It’s simply a matter of different design priorities/philosophies from BetaFlight. It doesn’t make one right and one wrong, just different. There is curently no F7 support in dRonin FWIW.

    WRT the Matek405Ctr, @KevinandEric has been instrumental in getting that target flying, although we are seeing some odd behavior. He’s seeing some lateral drift in the gyro, and we’re not sure if it’s the board(s), the installation(s), or the firmware. I’ve not had a chance to install and fly my board. From a feature and quality perspective, my sample of one looks good, IF it doesn’t have drift issues. It’s odd, as the MPU6000 is usually pretty well behaved. The Matek405Ctr is soft mounted, and that might have something to do with it, don’t know for sure.

    Much more could be written here…..and probably will be. 🙂

    #59245
    Kevin_Erik
    Moderator

    The Matek F405-CTR has been one of the best boards I’ve tried, considering I’ve gone through 5-6 boards of various makes within the last year.

    Now as previously mentioned, both my Matek’s (Tri-Baby and 5″ Chameleon) have been experiencing an annoying left-forward drift but only towards the latter half of a battery. This leads me to think that I’ve either got a bunch of temperamental motors or the BLHeli_32’s timing (Automatic) and De-Mag (low) is not sufficient. (warm motors acting out ect.) It’s not so bad that you’d really notice in flight until I take my hands off the sticks. Which after about 5-6 seconds I’ll need to provide correction to keep from plowing into the dirt. Further more, when I use an 6S-LiPo, I clearly have what sounds like a desync. (2207 1900kv motors) I’m currently working on this as we speak as it’s likely that both issues are related.

    Beyond that, I’ve tried everything short of buying new Motors and ESC’s.
    -Soft-mounting Flight Controller.
    -Soft-mounting motors (between the motor / frame and the screws as well)
    -Lowering the Gyro filtering within dRonin.
    -Re-tuning dRonin to be less sensitive.
    -Re-calibrating the Gyro / Accelerators.
    -Trying different brands of Propellers
    -Hash Language (Done frequently and excessively)

    Currently I’ve ordered a few replacement Bells for the 2205’s and 2207’s that should allow me to hot swap and better localize the problem. (Fingers crossed) Should that not work, I’ve a few T-Motor F-80’s that I may try assuming there not totally overkill on the Tri-Baby.

    Now if that weren’t bad enough, my FPV Feed keeps turning Black-n-White on me. I’ve been working with Runcam and Matek extensively but thus far have not managed to improved the situation. (Yes all three of my copters do this on four separate displays) *See the attached image from today’s flight*

    Attachments:
    #59248

    Hmmm yeah didn’t think about the through holes. Pretty stupid design, but I guess they made it that way to save space.

    I wouldn’t mind making dRonin the official tricopter and bicopter firmware and make setup videos for it. The Triflight firmware is getting pretty old now that Lauka no longer has the time to make changes.
    Would be cool to have a quirky copter with a quirky firmware.

    It’s quite difficult the choice of which FC to carry.
    Price, performance, features and quality needs to be well balanced.

    #59250
    jihlein
    Participant

    Mulling it over a bit more, the Kakute would be a good board for bi/tri/quad copters, with or without FPV. It won’t support navigation, as there is no external I2C for the mag. It has enough uarts for serial rx, SPort telemtry, all with the necessary inverters onboard.

    Note there is no PPM receiver support.

    Personally speaking I prefer external data logging, and there’s enough uarts to support high speed logging to an OpenLagger (like an OpenLog, except capable of much higher speeds).

    I see this board aimed more at the bicopter, baby tri, and mini tri. While it would also work on the V4, I don’t see it as an ideal fit do to the lack of navigation support and extra PWM outputs for gimbal control, etc.

    Within these constraints, and also the thru hole soldering rather than pads, it might be an okay choice.

    #59256
    Kevin_Erik
    Moderator

    So whats the life-span of the FC expected to be?

    All too often if a mfr doesn’t do well or if the tech changes, gear can hit EOL pretty quickly.

    #59258

    @jihlein I was mainly thinking of this board for the bi/baby/mini. Not many people do navigation with these (to my knowledge) It’s the V4 I get those questions for.
    I’m liking this board and I read good things about it. I think it would be enough for most users at an ok price.

    @Kevin_Erik Good question. Having a 3rd party FC makes it a whole lot easier for the rcexplorer shop. If something industry changing happens overnight we can start carrying such a board without having to worry about having too much overstocked outdated tech.
    I would have loved to design a new RCExplorer board but the cost and risks are too big for us at this point.

    But I think the F4 board will last for quite a while. Having it being the tri/bi board with dRonin would make it possible for us to keep it alive for a longer time as well. But as you said. Things can happen quickly.

    Terje is currently building a Bicopter with the Kakute F4 V2 board to see if it works as expected. He or I will report back the results 🙂

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