Category Archives: SG Adventure Mini Quad

OpenPilot CC3D released by HobbyKing

Posted by on September 25, 2014 No comments

In the past two months HobbyKing released the HK Pilot32 (alternative of the Pixhawk) and the Acro version of the Naze32 board (info and pictures in my previous post).

Today they released another great and popular flight controller: the OpenPilot CC3D. It is also an 32bit controller like the HK Pilot32 and the Naze32. Hardware and software are completely open sourced. More about the project you can find on the OpenPilot website.

The CC3D version is more like the Naze32 Acro. It is also so small: just 36x36mm and only 6 grams. The processor is the same as on the Naze32, STM32F1 and not the faster STM32F4 like on the HK Pilot32. Gyro and accelerometer on the CC3D is the popular MPU6000. The Naze32 Acro has the MPU6050. Both OpenPilot CC3D and Naze32 Acro haven’t any barometer or magnetometer like the OpenPilot Revo or the HK Pilot32.

So both flight controllers are a kind of competitors. The OpenPilot CC3D is priced at 31.99$ and the Naze32 Acro at 24.99$. Although you don’t need to solder any pins on the OpenPilot CC3D. It comes ready to fly. So far HobbyKing is doing great job by offering another open source flight controller. It will be a good alternative for my SG Adventure Mini Quad 🙂

Source: HobbyKing.com

Custom frames and flight controllers

Posted by on September 23, 2014 5 comments

This will be a mini how-to about custom frames (like my SG Adventure Mini) and the motor mixer settings for different flight controllers. I already described a bit about the settings on KK2.0, KK2.1.5 or the Naze32.

There are two methods about getting the right numbers for your flight controller. The first one is by using the angles between the arms and the roll and pitch axes. The second one is by getting the distance from every motor to the Roll and Pitch axes. I used the first one for setting the mixer editor on my KK2.0 board about two months ago, because I saw this method in a HobbyKing-video on YouTube.

Although I will use the second one in the future because it is more accurate. Why?

Using the first method we use the angles between the motor arm (or in a bit asymmetric frame the line between the motor-shaft and the center of where the flight controller is mounted) and the roll and pitch axes. Then use the sine(of this angles) = the value we use for our flight controller. This is actually almost the same as method two:

For the angle α, the sine function gives the ratio of the length of the opposite side (the distance from the motor shaft to Roll/Pitch) to the length of the hypotenuse (this is the distance from motor shaft to the center of the flight controller).The controller uses only the ratio between these two sine functions and in that way it knows the ratio between the distances to Roll and Pitch and where the motors in space are.

Using the method with the sine of the angles would be 100% ok, if all 4 arms have the same length and are mounted in the same distance from the flight controller. On my SG Adventure Mini Quad the distance from the front two motors to the FC are 135.3mm and the distance from the rear motors is 136.2mm. That is less a mm. Using the method with the angles would be no problem at all.

To be 1000000000% accurate 🙂 I am using the second method, getting the ratios of every distance to the Roll and Axes by measuring these. How to do this:

Measure all the distance from every motor to the Roll and Pitch axes. Take the biggest nominal value and divide all the distances by it. In that case every distance is a ratio of the biggest one.

In my case this is the distance from Motor 1 (Rear right) to the Pitch = 108mm. Dividing:

Motor 1:

  • Pitch  108/108 = 1 (For the KK2.0 or KK2.1.5 Motor Mixer this means 100).
  • Roll     83/108 = 0.768 (KK boards 77)

Motor 2:

  • Pitch   83/108 = 0.768
  • Roll  106,9/108 = 0,989

And so on for the other motors. Note that the motor layout in MultiWii/Naze32 are not the same as in the KK or the APM.

And to show you, that there are (almost) no difference in the calculation methods:

Sine(38) / Sine(52) = 0,782; 38 and 52 are the angles to Pitch and Roll for Motor 2 on my frame.

0.768 / 0.989         = 0,776; This difference is so small, that there is no problem for the FC.

As said both methods work well, but the second one is more accurate when using arms with different length. I hope this “problem” with asymmetric frames, like mine or TBS Discovery, and the right settings is more clear now.

Naze32 custom motor mix for V-Type frame

Posted by on September 21, 2014 14 comments

I have the Naze32 board on my new SG Adventure Mini Quad. It is a custom V-Type frame like the TBS Discovery and the Dead Cat frame. The Quad flew great with the Naze32 as well with the HK Pilot32 with the standard QuadX configuration, but I wanted it to be done as it should be. I have done the measurements in CAD, but also printed it on A4 so you can check it too.

What we need for the Naze32 custom motor mix are the distance from every motor shaft to the Roll and Pitch axes.

CustomMotorMix

Connect the Naze32 to the Baseflight configurator and go to the CLI-tab. Type “cmix” in the command line to load the custom mix. We need to define the Throttle, Roll, Pitch and Yaw for every motor. This should be for Motor 1 (Rear Right):

cmix 1 1 –1 1.3 –1

What this mean: cmix 1 defines the motor number. Then we have the value for the Throttle, also 1. The next two values a for the Roll and Pitch and this is how get them: Take the dimension from motor shaft 1 to the Roll and Pitch axe and divide the values by the distance to the Roll axe (that way we make every other value a factor of that one):

Update 23.09.2014: You can also take the biggest distance value from any motor of the four motors and use it, as factor for the other ones (divide all others by it); then all other values will be smaller then “1”. This is not relevant for the Naze32 board, but for the KK2.0 or KK2.1.5 motor mix, where no values bigger than 1.27 are allowed.

I also wrote a more detailed how-to of the “problem” with different frame types.

Roll: 83 / 83 = 1 (it should be negative for the motor 1 and motor 2, because these are on the right of Roll)

Pitch: 108 / 83 = 1.3

The last one for the Yaw axe should be nominal equal of the Roll value. Yaw value of every motor could be 1.000. It is negative because the motor 1 spins clockwise.

Motor 2 (Front Right):

cmix 2 1 -1.28 -1 1.28

Distance to the Roll and Pitch axes are: 106,9mm and 83mm. Divide both values again by the value of the Roll distance of Motor 1, so by 83. (It is just a coincidence that my motor1 roll distance and motor 2 pitch distance are both 83mm).

Roll: 106,9 / 83 = 1.28

Pitch: 83 / 83 = 1

Yaw is equal to Roll, but positive because the motor 2 spins counterclockwise.

The values for Motor 3 and Motor 4 are nominal the same. So we have for motor 3 and motor 4:

cmix 3 1 1 1.3 1

cmix 4 1 1.28 -1 -1.28

The sanity check should be “OK OK OK”. I didn’t get this message, but it is not a problem. Although the Mini Quad flew even better with the new settings.

SG Adventure Mini Quad

Posted by on September 21, 2014 3 comments

This is the third revision of my SG Adventure Quad, that I made back in may this year (link). This is a short review of the Mini Quad (the normal/bigger one uses just longer arms for 8” or 10” propeller).

The SG Adventure Mini Quad is a V-Type frame. I went on this type, because I wanted something different from the Mini H-Frame hype and I love the asymmetric frame 🙂 It is also designed for mounting an action camera and FPV gear.

Details about the frame:

  • V-Type asymmetric 260mm frame (measured motor shaft to motor shaft diagonally)
  • Weight: only 83 grams 80 gram (v4)
  • Material: High quality carbon by SGL Carbon and made in Germany

Features:

  • Designed to mount a GoPro or a Mobius camera on the front.
  • Use of 5” or 6” propellers.
  • Mount of almost every flight controller: Naze32, KK 2.1.5., Crius (or clones such the HK AIO Board), OpenPilot, AutoQuad, MultiwiiPro, DJI Naza and also the bigger ones APM 2.5 and Pixhawk.
  • Motor mounting holes: M3 19mm x 16mm; M2 16mm x 12mm (T-Motor MN1804) and M2 12mm x 12mm for the small T-Motor MT1306.
  • Distance between the two center plates is 6mm, so there is a place for small receivers such as the FrSky D4R-II (by using the additional carbon spacers).
  • There is a cover plate for direct mounting of GPS, FPV gear and covering the flight controller (additional weight of 8g).
  • Mounting a Tarot 2D Gimbal (v4 frame).
  • Cover plate for LEDs on the front (v4 frame).

Photos and more details:

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The arms and the small parts are made from 3mm carbon, the other plates from 1mm carbon.

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As said the center plates can be used with longer arms for mounting bigger motors and bigger props.

On the SG Adventure Mini I am using the MN2206 2000kv motors from T-Motor. A budget version could be the Multistar 2206-2150kv Baby Beast motor from HobbyKing.

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For the flight controller I used some spacers. It is not necessary, but so I have some space for ESC or receiver cables. On the down side there are holes for battery strap. Between these could be mounted a standard 30.5 x 30.5mm power distribution board, such the one I used instead of the cable harness.

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I also used 8 – M3 x 16mm screws for assembling the frame and 16 – M3 x 6mm for mounting the motors.

I had a big problem mounting the ESCs, because I only had Afro 30A. Ideal would be the Afro 12A, HK BlueSeries 12A, KISS 12A or KISS 18A ESCs. Although the Afro 30A are big, I succeed mounting them by cutting the wires. The Afro 30A are a bit heavy too, almost 100 grams with the power board and cable.

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Fully assembled without the battery the Mini Quad weights only 367 grams. With smaller ESCs there could be definitely saved another 50 grams, which would be great for the mini and the flight time. And there is so much free space, when using the small Naze32 instead of my HK Pilot32.

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Update 29.09.2014: Here two more photos with the new carbon 6×2 propellers.

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I made some flights today for the first time with the Naze32 and the Mini frame and got about 15 minutes with the 2200mAh 3S battery. Still waiting for some small carbon props for better look and experience.

Production costs are a bit higher because of the quality material from SGL Carbon and the production in Germany.

Let me know, what do you think about my mini frame and if there is something to be done better 🙂

Update 29.01.2015: Clean Install & CleanFlight & Naze32 Carbon Cover

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Update 21.03.2015: The actual version is v4 now. Changes:

  • Design changes: the frame is much lighter, looks better and has better aerodynamics.
  • Front and rear arms are the same now.
  • SG Logo on it 🙂
  • Possible to mount an Tarot 2D Gimbal on the down side.
  • Tiny cover plate on the front, including holes for LEDs.
  • Redesigned the 3mm carbon spacers. Motor cables can go directly to the inside of the frame.
  • Redesigned the third cover plate. FPV antenna can now be mounted on it.

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Update 03.06.2015: Added a build log for an FPV Racer with that frame here.