Tuesday, May 27, 2014

Motor benchmark

I'm currently searching for the best match (prop, battery) with the Hobbyking BL1230 5300kv Brushless Inrunner Motor.


The specifications that hobbyking provides:
Battery: 3s (11.1v)
RPM: 5300kv
Max current: 8.5A
Dimension: 30mm x 12mm, 38mm(with shaft)
Diameter of shaft: 1.5mm
Length of front shaft: 8mm
Weight: 15.3g

After running my first benchmarks I noticed these specs are incorrect and misleading. It is not save to run this motor with a 3s lipo even at almost no load the motor gets extremely hot when connected to a 3s lipo. If you want a reasonable lifetime for this motor then use max 2s lipo. But a 1s lipo is the best way to go with less heat, best efficiency and longest lifetime. Also note that the 8.5 max current rating for this motor is at 1 Cell. 8.5 amps on a 3 cell will burn your motor instantly!

lipo comparisson benchmark:
- all benchmarks fixed prop size 3x2 inch.
- all benchmarks fixed output thrust level at 50 grams.

- all benchmarks fixed to 3 min run.

Battery Power In Temperature
3 Cell 23 Watt  > 70°C
2 Cell 15 Watt 62 °C
1 Cell 9 Watt 30 °C

As you can see from the benchmarks. When demanding the same output value of 50 grams thrust with the same motor and prop the input power value and the motor temperature changes depending on the lipo cell count. 

my opinion:
3 cell: don't do it!
2 cell: only if you have no other option.
1 cell: best choice.

Monday, April 14, 2014

MultiWii Joystick First Release

Here it is! the first release of the MultiWii Joystick software.

I did a flight test with my foam quad equiped with the hobbyking Multiwii MWC FC Bluetooth Module. The MultWiiConf software, running on my laptop on Win7 64b, connects to the quad via a virtual serial COM port over wireless bleutooth. The Gamepad is connected to the laptop via a standard USB port. The MultiWiiConf software grabs the gamepad data and sends it to the quad via the MultiWii RCSerial protocol.


I have create a complete support webpage and uploaded the software and source code to:
http://www.multiwii.be/multiwiijoystick

Have fun!

Thursday, April 3, 2014

Bluetooth and joystick support

I bought a hobbyking Multiwii MWC FC Bluetooth Module to have telemetry and to replace my analog 4channel reciever at the same time.

The module creates a virtual com (serial) port via the wireless bluetoorh communication. It is plug and play and works very well with the MultiWiiConf utility. So having acces via my laptop or pc to live in flight telemetry data is very easy to setup with this module and the MultiWiiConf software.

But I want to control and fly this quad via my laptop or pc with a normal joystick or gamepad. So I don't need the standard pwm reciever any more. For days I looked on the net and even started a forum thread at the multwii website to find an application (laptop, pc, windows compatible) that could do this. I found nothing so I started to make it myself.

I currently have a Beta version ready. First is a small java application that lets the user select the desired joystick or gamepad and let the user link sliders or buttons to channel 1 - 8. The configuration can then be stored in a file.

Then I have adapted the official MultiWiiConf sourcecode so that is reads this configuration file created by joystick configuration application.
It initializes the joystick or gamepad, reads its values and sends it via the RCSerial protocol to the flight controller.

The movie below is a little proof of concept. The flight controller is connected to my laptop via an USB cable. Because I have no RC reciever connected you see my RC channel go crazy. Ones I press the new joystick button the joystick or gamepad data is send to the flight controller via the virtual com port (over usb cable). Normally this will also work in combination with the wireless bluetooth module because it has the same type of virtual com port.






Tuesday, February 18, 2014

Pid tuning

So I tried to tune the pid settings. Before this I mounted the motors in a litle angle instead of 100% vertical. This gives me a better yaw control and overall stability. See my MiniH-Quad blog for more details on this subject.

During the test flights in order to find a good pid configuration I had some crashes (pilot error :p ). In total 3 motor arms broke and the outside prop protection broke at 6 places. But the fix is easy. Just glue evertying togheter with 5min epoxy and the quad is ready to go. But no motor and no electronics were damaged.

I think I'll stay with the current pid settings as used in the testflight in the video. So the next stage will be the integration of altitude hold or bluetooth control depending on what will be deliverd first.



Tuesday, January 28, 2014

Prop protection foam frame

So here it is my final frame for tis project. I'll use this indoor frame to add features like altitude hold with IR sensors and wifi or bluetooth telemetry and flight control so that I don't need the analag RC transmitter and reciever any more.

This frame looks like rubish. And yes it is rubish. Unfortunatly I ran out of foam so I had to cut out small pieces from the previous frame en glue them all togheter with a lot of epoxy making it a little bit heavier. The total weight of this quad incl 1300mAh 2 cell lipo is 285gr.

setup:
3x2 inch props (motors mounted upside down)
- 1300 mAh 2 cell lipo
- Analog FM 40mhz RX/TX

how-to:
Cut 5 foam strips with dimensions 20x40x200mm
Cut 2 foam strips with dimensions 20x40x260mm
Cut 2 foam strips with dimensions 20x20x120mm
Glue these foam strips with epoxy
In the center I cut out some foam where I mount the 2s 1300mAh battery.
The motors are attached to the foam arms with normal tape.
The props are mounted directly on the motor shaft. These props have a 1mm hole. You need to enlarge this hole with a "1.4mm" drill. Then you can push the prop on to the motor shaft.

review
I kept the same PID settings from the previous H-Frame. But this frame was flying much better with these settings. Because the battery is mounted in the center this certenly improves the stability.

Something I'll have the tune before I'll experiment with the IR sensors is the yaw authority and control. In order to yaw the copter has to create to much difference between the CCW and CW motors (props) causing it to become unstable. I also need to check to smoothen the RC control because it is reacting quick agressive on small stick inputs.













Wednesday, January 15, 2014

Foam H-Frame

The flight test with the X frame showed that the set of chosen components is good for further development. The initial goal was to make a small frame with prop protection. I have first created a small micro H-frame without prop protection. Just to see if the flight controller board can handle this.


setup:
- 800 mAh 2 cell lipo
- Analog FM 40mhz RX/TX



how-to:
Cut 4 foam strips with dimensions 20x30x120mm
Glue these foam strips with epoxy
In the center I cut out some foam to allow all electronics to be connected
The motors are attached to the foam arms with normal tape.
The props are mounted directly on the motor shaft. These props have a 1mm hole. You need to enlarge this hole with a "1.4mm" drill. Then you can push the prop on to the motor shaft.



review
Because the NanoWii board was already oscilating with the previous 30cm x-frame and this H frame is half the size, I decided to lower the PID values before the first test flight. As you can see on the movie It still need some PID tuning to fly smooth. But fact is that again this setup on this small frame can fly. So up to the next challange...







Sunday, January 12, 2014

Upgrade flight controller

Flying with the i86l board was really hard labour. Almost inpossible. I could not find a good PID setting to let it fly stable and smooth. So I mounted a NanoWii flight controller board. Now it fly's much better. I got standard pid's and you can see and hear that is oscilates from time to time. So pid tuning is needed but with the nanowii board I can continue this project.

outdoor flight test with nanowii board mounted

Friday, January 10, 2014

Foam Copter



This is the first version of my diy foam quad. It has a 30 cm X frame made of foam. The goal is to make it even smaller and make an outer prop protection foam ring. The total weight of this quad is 215gr including lipo.

setup:
- 800 mAh 2 cell lipo
- Analog FM 40mhz RX/TX

how-to:
The foam parts are just glued together with epoxy.
The foam arms are 20x20x150mm.
The center section is 60x60mm
The motors are attached to the foam arms with normal tape.
The props are mounted directly on the motor shaft. These props have a 1mm hole. You need to enlarge this hole with a "1.4mm" drill. Then you can push the prop on to the motor shaft.


review
It looks like the i86L flight controller doens't like small frames. I had this controller on heavy 60cm quads and it works great. But on all my small/light quad's I can't get this flightcontroller to fly smooth and stable. So I'll try the Nanowii next time.

The 1230 5300kv brussless inrunner can provide +170 gram of thrust on a 2 cell battery with this 3x2 prop. But then it gets extremely hot after just 2 seconds. At 100gr thrust it consumes 36 watts and gets warm. As soon as you demand more power it gets hot immidiatly.