Hands on: FrSky XSRF3O flight controller

Since I just started to add support for "old" FrSky XSRF3O flight controller to INAV (expect this in a release after 1.8) it might be a good idea to share few words about it.

FrSky XSRF3O flight controller in a box

First of all, it comes in a box. Why am I mentioning this? Because none of my flight controllers, and I own at least more than a dozen, came in box. C'mon, this is huge! I'm not joking, this is really a nice touch.

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And the most popular flight controller for INAV is… (August 2017 edition)

More than 2 months after previous “What it the most popular flight controller for INAV“, welcome to second edition.

I mportant, this is not the number of boards flashed with INAV, but rather number of times a board was connected to Configurator!

This counts TARGET software name, not retail name. For example, all clones of Naze32 will be counted as Naze32

Data was taken in August 2017, multiple connections during single user session are stored as single entry.

  1. SP Racing F3 – 25% of all boards, lost 4 percent points
  2. Omnibus F4 Pro (aka v2 aka SD) – 15% of all boards, gained 5 percent points
  3. Naze32 rev. 5 and 6 – 13% of all boards, lost 6 percent points
  4. Omnibus F3 – 12%, lost 1 percent point
  5. Naze32 older than rev. 5 – 7%, gained 2 percent points
  6. Omnibus F4 v1 – 4%, gained 1 pp.
  7. Omnibus F4 v3 and v4 – 3%, first time in TOP 10
  8. SP Racing F3 EVO – 3%, lost 2 pp.
  9. CC3D – 3%, lost 1 pp.
  10. AnyFC F7 – 1%, first time in TOP 10

Other targets have 14% in total.

This data also says something about CPU generations distribution:

  1. STM32 F1 – 27%
  2. STM32 F3 – 47%
  3. STM32 F4 – 25%
  4. STM32 F7 – 1%

What changed comparing to June?

  1. First F7 board appeared in TOP 10!
  2. F1 and F3 targets are loosing market share, while F4 and F7 are more and more popular
  3. Naze32 is no longer second most popular board
  4. OpenPilot Revolution and Airbot F4 (more less the same) are out of the TOP 10
  5. Boards with integrated OSD are more and more popular. They already have 47% of market share

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Very custom FPV quadcopter for my daughter

When few months ago my older daughter (10 years old) started to express interest in FPV quadcopters, I was both happy and concerned. Happy, since I would have someone to fly with. Concerned, since she has no idea how to fly, I do not have a quadcopter for her and there is a big chance she will get bored fast. So, instead of getting her a brand new, cheap, standard off-the-shelf drone, I checked my repository of “spare” parts and drones, purchased this and that and week later “Omlette du fromage” came to life…

Scarab Knife 200 cartoon sticker bomb

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Flight Controller Soft Mount – is it worth it?

Is it worth to soft mount flight controller? Are gyro pads I recommended here better than rubber stand offs? I feel that they are better, but I do not have any solid data to prove it. So I can only tell, that I find them better and that is all. But, I can answer the question is it worth to soft mount flight controller at all. The answer is YES and here is a proof…

The problem of twitching motors

After I updated my 5″ racer to stronger motors (EMAX RS2205S 2300KV over RS2205 2300KV) I noticed something very very irritating: twitching motors. When throttle was in more less middle position or after rapid throttle change, twitching from motors was very audible. Quad was flyable, but performance was very low. I had to reduce yaw P gain by more than 50% not to see those twitches in FPV footage!

Blackbox log revealed the truth: from time to time, strong vibration was getting into yaw gyro traces. I also localized the source of those twitches: stronger motors with more torque and higher radial acceleration were able to shake whole machine when frequency was close to the resonance frequency of the frame.

hard mount twitch example

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And the most popular flight controller for INAV is…

Did you ever wondered what is the most popular flight controller? Hardware I mean. I can tell you 🙂 OK, maybe it will not be a full truth, since I have data only from INAV, but assuming that distribution for Betaflight and Cleanflight is similar, we might know what is happening…

Important, this is not the number of boards flashed with INAV, but rather number of times a board was connected to Configurator!

This counts TARGET software name, not retail name. For example, all clones of Naze32 will be counted as Naze32

Data was taken in June 2017, multiple connections during single user session are stored as single entry. Continue reading “And the most popular flight controller for INAV is…” »

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FC Soft Mount With Adhesive Pads FTW!

I will not try to proof if you should soft mount a flight controller on a racing drone. I will only say, that few months ago I was against it, but lately I changed my mind. Stronger motors, stronger magnets, more torque, more speed and out of nowhere, incredible amount of noise can be fed into gyro signal. Sure, this is not required, but motors, ESCs and battery will thank you when you soft mount flight controller. Less, noise, less restrictive filtering required, lower signal delay, better flight performance.

In most places over internet you can find either a rubber standoff or double sided tape solution. Sure, that works, but there is something better. Dedicated, double sided adhesive, vibration dampening pads. There are many sources, and many names. I'm using Sekisui brand. Check ebay, Amazon, HobbyKing. Look for gyro pads, vibration pads, vibration dampening. I do not want to advertise any particular seller, so you are on your own here.

Sekisui adhesive gyro pads

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AnyFC F7 and DIY buzzer for INAV

Because both original and Banggood clone of AnyFC F7 flight controller and missing buzzer support, its usefulness is somehow limited. There is no dedicated pin and driver. Next release of INAV (1.7.2) will finally solve this problem by reusing Motor #9 output as buzzer output.

But, some additional hardware will be required. To be precise, single n-channel signal MOSFET transistor like 2N7000. Connection diagram is shown below.

AnyFC F7 Buzzer driver with 2n7000 mosfet transistor

And this is how it can be soldered together.

AnyFC F7 Buzzer driver with 2n7000 mosfet transistor

AnyFC F7 with buzzer

That is all. Simple, right?

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Hands on: Omnibus F7 Flight Controller

Thanks to Airbot I got my hands on a new STM32 F7 flight controller: Omnibus F7.

Before we proceed, small note.

I am a huge fan of F7 flight controllers. In a year, they will be a main line of high performance FC on the market. STM32F7 with built-in UART inverters solves so many issues STM32 F4 boards are facing. But, F7 are not there yet. Currently available boards uses STM32F745 CPU in 100 pin packages. They are just too big to comfortably fit 36x36mm format. You place CPU and most of the PCB is taken. Than means there is no space left for either connectors or OSD for example. What we are waiting are FC with STM32F722 in 64pin package!

Omnibus F7 flight controller top view

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