emile's Posts (7)

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Testing X8 configuration without two propellers

Yesterday I had a few tests with our Tiger Shark in Octa Quad configuration.

The tests were made to see how the copter would cope the loss of one or two propellers.



Obviously the test was in a ideal condition where the propeller just loosens and falls off the Octo.

The test was done by removing first 1 propeller, then two propellers spinning in opposite and same direction.


Without 1 propeller the copter flew as it had all the propellers. There was no feeling of something wrong. It took off and landed easily.


Taking off two propellers spinning in the same direction (lower front left and lower back right) resulted in a copter that in take-off yawed a little. Once the I term build up, it was perfectly straight. It was a little unstable due to the fact that two arms were "stronger" than the others, but generally it was perfectly stable even with some wind.




Taking off two propellers spinning in same direction (lower front left and right) resulted in a copter trying to move forward with quite a pace. I took a little pitch back to keep it still, but the overall stability was amazing.....


X8 will not take the loss of two propellers on the same arm, that would result in a crash, unless the recent algorithm gets published and then implemented in ACM code. :)


The code is based on APM:Copter 3.1.2 but runs on VRBRAIN.

Propellers are 13x5 T-motors on the upper and Graupner 13x8 on the lower.

Motors are 3508-700KV with 10Ah 4S battery.

Total weight was about 3.0 Kg.


Thanks to VirtualRobotix.it for the frame and the electronics, and thanks to the APM:Copter dev team that allowed us to fork and use their code, that is progressing fastest than speed light!






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VirtualRobotix new products revealed



It is with great pleasure that we are able to present the result of our latest work.

In the last 4 months we designed, built and tested 2 frames and 2 Gimbals.

This is just a preview of these new products, production will start in the next month and pre-orders are available through our freshly re-designed web site www.virtualrobotix.it


Black Ops Drone aka B.O.D.

A multipurpose drone specifically designed for gaming and simulated wars. It is a plastic 2 shell frame very resistant and light weight. It is splashproof and can mount a small FPV camera on front. It can be used with many different payloads and mounts 3508 motors with 13" propellers.





A powerful, tough and yet simple frame built with only 3k twill carbon fiber and High grade Aluminum.

The frame is designed so that X4 or X8 configuration is possible without any other add-on.

It is extremely tough and resistant, and host propellers up to 14" or 15" .

Typical configuration is with 3510 or 3508 Motors with 13" props, but also 40mm. motors can be mounted with no problems. The arms can be shifted in 1,5cm. steps to allow bigger props (15").




A professional 3 axis Brushless Gimbal built with 3k twill carbon fiber that is able to carry 3Kg. of payload.

This is our masterpiece. It uses high quality Stainless steel bearings and it is integrated with adjustable height landing gear.

It weights about 600gr. and it offers super smooth camera compensation.





The same Shockwave Gimbal can be used on our hand-held system allowing camera operators and professional photographers to obtain perfect stable images. The hand held mount can be equipped with remote control for PAN, TILT, ROLL and ZOOM.




A 2 or 3 axis Gimbal designed to fit the most common and light to medium cameras such as:

Sony NEX xx

Canon M series

Sony Cybershot VX420 or similar

Totally built wi Alu and Carbon fiber it is extremely light and it is sold with an antivibration plate suitable for any frame. It's weight without mootrs is 280gr. and is perfectly able to carry 300-400gr. of payload.



Please refer to www.virtualrobotix.it for more details and don't hesitate to askany questions.

The VirtualRobotix team


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The future of UAVs is...


Some GPS artistic drawings...

 Hehe, just a teaser for my yesterday's tests on VRBRAIN with latest 2.9 firmware! VRBRAIN uses the powerful ARM STM32F4 CPU and runs with the actual 2.9 firmware codebase.



This is the location of the code and DFUs: http://code.google.com/p/vrbrain/downloads/list

I have also set up a small and rather incomplete "how to" to upload the firmware into the STM32F4 ARM Microcontroller 

Man!, never had so much fun with the Auto mode! I am using a UBlox GPS on a Hexa frame with 10x4.5 APC props.

The main difference between our code and the original Arducopter one is that we drive our main stabilization loop at 400Hz (instead of 100Hz) and get samples from the Gyro and Accel at 1000Hz (instead of 100Hz) with only 10% CPU time used.

The filter of the MPU6000 is set to 98Hz, although the Alt_Hold with the accelerometers worked very well.

Some perf mon :
VRBRAIN @ 2500Hz-400Hz
Function:   cpu   avg(ms) max(ms) Hz
fast_loop   10.31 0.257   0.325   400.0
fifty_hz    0.20  0.040   0.093   50.0
gcs_check   0.16  0.004   0.118   350.0
update_GPS  0.07  0.014   0.105   50.0
medium_loop 0.04  0.007   0.029   50.0
super_slow  0.02  0.189   0.277   1.0
slow_loop   0.01  0.012   0.032   10.0
free CPU:   89.17 8922

Here is the picture of the Waipoint path, as you can see I am not good in drawing, but the path was followed very well.




One thing that impressed me was the alitude, in all the auto mission only 1 meter between max and min.

The new altitude hold with use of accels is doing a great job also in autoland and auto-approach.




To all the AC team a big thanks for the huge work!

And thanks to Roberto and VirtualRobotix for his VRBRAIN!

Original Blog Post : http://www.virtualrobotix.com/profiles/blogs/the-future-of-uavs-is



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FPV on holiday

My wife was nice enough to let me bring my quad and FPV gear on vacation :)

This is the result.


Had dozens flights using Multipilot32 with MPU6000 and latest ported Arducopter32 2.6 firmware.

Unfortunately the quad had some vibration problems and wind was always quite strong.

I think it's time to change motors and frame....

Had a lot of fun. This is my first edited video so please be nice with comments :)




Thanks to Roberto for his MP32 + NAVI2012

and thanks to the Arducopter dev team for their great work!

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Add a backup battery on the MTK GPS module.

Hello Everyone, we all know our GPS board (the one that comes with the APM1) has no battery to backup data.


This has the disadvantage to make the GPS not very precise in the first minutes after power up and that every startup is a cold startup (at least one minute to get a 3D fix).

This is because the GPS needs find the satellites without a previous almanac (that is information on position of the satellites visible in that location at a specific time).

As you understand almanac is VERY important. Also considrer that the almanac is sent by every satellite and requires 12.5 minutes to transmit (or so).

From Wikipedia:

 "Finally, the almanac allows a single-frequency receiver to correct for ionospheric error by using a global ionospheric model. The corrections are not as accurate as augmentation systems like WAAS or dual-frequency receivers. However, it is often better than no correction, since ionospheric error is the largest error source for a single-frequency GPS receiver. Each satellite transmits not only its own ephemeris, but transmits an almanac for all satellites"

Of course this is not sufficient to have a perfect position: sky visibility, surrounding objects and number of satellites are the key factors. 

This is why after a FIX (fixed blue led) number of satellites is very low (5 to 8) and this get higher (10 or 12) after some time of flying.

So, because of this, I decided to bring up an old hack made by Dcaspi, an old friend who worked also on the former Ardurpirates code.

The hack requires some soldering skills, so I suggest you to do it only if you are confident with it.

Beware if you fry the board or GPS unit, I cannot (nor Dcaspi) be responsible for it...

This mod works and has been used for a while.

This is the original location:


Have fun!



If you use the DIYDrones MediaTek? GPS, you're probably aware of the fact that, on each activation, it make take a very long time to get proper satellite lock. The reason is that it always starts from scratch; it is not aware of it approximate geographic location, not of the time.

The reason for this is lack of backup battery. Data is completely erased once you disconnect the main battery.

The GPS module itself has a backup battery input. Here we show how to connect an external battery to that input.

What You Need

You will need a a battery holder and a small, 3V, coin-shaped lithium battery. These can be purchased at any DIY electronics store.

I also used a piece of perforated prototyping board, but this is for convenience and not a must.

How It's Done

Below, you can see the GPS module board layout. Cut one trace as shown, and connect the two leads from the battery holder to the marked places.


Here is how the setup looks:



This is how it looks from below. Note the place where the trace is cut:


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Multipilot32 and OILPAN IMU - Quick Start guide

If you want to have a go at the MP32 from www.virtualrobotix.com, take advantage of the powerful 32bit ST ARM Cortex-M3 processor and would like to use your OILPAN with the great software the DIYDrones developres are developing, this is a small guide to get things started.

It will cover the biggest steps to configure the hardware and firmware.

Roberto has done a very good job, and since he lacks a bit in end user documentation (well that's tipical for almost every developer!!) I decided to give him a little help. 

The code is ported form the 2.0.39 AC2 firmware and is is up-to-date with recent enhancemets. The planner will work just fine (at the time of writing 1.0.54)

The above is a video made by Roberto itself explaining setup for both the VRIMU and the OILPAN.

Below are details on the code to modify.

Have fun!


For more information please refer to www.virtualrobotix.com and http://code.google.com/p/multipilot32/ for the project home.


What you need to start

To start with the new Hardware set-up you need the follwing:

  • OILPAN rev H or older revision Foxtrap.



Before you can use the AC32 firmware you MUST solder two pin headers on the connectors shown below. You then need to short them in order to upload new firmware and fly! (you can use an old motherboard jumper plug to short the connector so you would be able to reuse your OILPAN on the old ATMEGA)




This is used to connect your MP32 to the Planner or to the CLI:



If you have an xbee working on your actual setup, you can use that instead of the USB-->serial, just hook it up to the Telemetry port as usual.


  • Telemetry pins soldered on the OILPAN see:



  • 4 cables female female to connect the usb adapter to the OILPAN on the Telemetry Port


  • a Magnetometer(Optional) HMC5843 or HMC5833L soldered on top of the Oilpan





  • You also need a bind plug to put the MP32 in firmware upload mode(see later...). Or you can use one female-female cable like the ones posted above.


First download and install software and drivers

Download the latest VRIDE Framework. At the moment it is the link here VRIDE. unzip it and place it in a folder like C:\MP32

  • You need to install drivers for your USB to serial adapter from here
  • You need to install DFU drivers for your MP32 board. You can find the drivers in the C:\MP32\drivers\mapleDrv\dfu\ folder of the VRIDE just downloaded.


  • Download the specifically modified firmware for the OILPAN from here OILPAN firmware. Unzip and overwrite the libraries folder in your C:\MP32 folder and the ACopter32 folder under the C:\MP32\Firmware\ folder


Installing the Mediatek GPS (DIYDrones)

At the time of writing only the Mediatek GPS from DIYDrones with firmware 1.6 is fully tested. The GPS needs to be attached directly on the MP32 board. To do this there are several ways. What I chose was to get a GPS cable adapter like the ones DIYDrones store sells and cut off one end that I solder directly on the board. You could also solder connector pins on both the MP32 and the GPS board and use a 4 wire cable.

This is a picture to explain what I did:


The 1st and last wire of the cable are not used, so you can cut them off. This is the schema on how to connect them:

MP32Cable Wire # / PinGPS Adapter Circuit Board
JP19-2 (GND)(2)(GND)
JP19-4 (5V)(5)(5V)
JP19-6 (Ser4 Tx)(4)(IN)
JP19-8 (Ser4 Rx)(3)(OUT)


This is where you will find the JPs on the board:


A picture shows were you can find the connectors:


Compiling and uploading the firmware

Configuring the VRIde

VRIDE is the "32bit version of Arduino". Is based on the LeafLabs? Maple IDE and uses a language much similar to the Arduino framework.

Once your hardware i ready and your drivers are finally set up you can start to open the vrobotix-ide.exe and in File-->Preferences choose the folder where you unzipped the VRIDE rar (eg. c:\MP32)



Then choose from the menu File-->sketchbook the Firmware-->Acopter32 sketch like in the Arduino framework. 


This is your new firmware ready to be uploaded. But before we can continue we have to check and modify a few parameters in the code.

Modifying the code before the upload process

To let the compiler know you are using the OILPAN and not the VRIMU we need to make a few changes in the code. Nothing too difficult.Future developements will not require you to make all this modification, so keep up for the news! So follow these steps:

  1. Locate the libraries folder in your C:\MP32 folder and open with a text editor like Notepad++ the following files:
    • AP_ADC\AP_ADC_ADS7844.cpp: be sure to comment out the #define VRIMU so the line would be //#define VRIMU like this:
    •      //#define VRIMU

    • If you have the old compass HMC5843 you have to open the file AP_Compass\AP_Compass_HMC5843.cpp and add a new line at the end of the defines: #define HMC5843 otherwise if you have the most recent mag, leave as it is.
    • Open the file AP_IMU\AP_IMU_Oilpan.cpp and comment out the //#define VRIMU and //#define VRMIMUIDG5000 line and add (if not present the line #define IMUOILPAN:
    •      #define A_LED_PIN   69  //37
      #define C_LED_PIN 71 //35

      //#define VRIMU
      //#define VRMIMUIDG5000
      #define IMUOILPAN

    • Open the file AP_IMU\AP_IMU_Oilpan.h and do the same of before: comment out the //#define VRMIMUIDG5000 and add if not present the line #define IMUOILPAN:
    •      #include "IMU.h"

      //#define VRMIMUIDG5000
      //#define ADC_OBJECT
      #define IMUOILPAN
  2. Locate the folder Acopter32 in the Firmware subfolder (C:\MP32\Firmware...\ACopter32). Then open and modify the following files:
    • In config.h:
      1. locate the //MAGNETOMETER section and modify the #define MAG_ORIENTATION as follow:
        #ifndef MAGNETOMETER
        #ifndef MAG_ORIENTATION
        #ifndef MAG_PROTOCOL
        # define MAG_PROTOCOL MAG_PROTOCOL_5843 // Default Setting
      2. locate the "Developer Items" section and modify as follow:
        // Developer Items
        #ifdef MP32
        //#define VRIMU
        # define IMUOILPAN
        //#define VRMIMUIDG5000

Ok, so now the code is ready to be uploaded.

Uploading the code

  • Now Plug the Bind Plug or one female-female jumper cable into the second input from the left of the MP32 (Called JP4_7, JP6_7 and corresponding to the 7th input of the old ATMega). Pins 1 and 3 must be connected toghether (The signal and ground pins)

This is used tu put your MP32 in firmware upload mode. When in this mode (and board powered) you will see a green led blinking on the MP32 board. This means you can start the upload process.

  • Plug the USB cable directly into the MP32 USB port. This is used as a power source and as a communication port.
Like the Arduino IDE, before uploading the firmware check that the code compiles correctly by clicking the Verify button. If code compiles, you can click on the Upload to board button.

Wait for the completed upload message in the VRIDE message window.


Setting up the firmware for first use

Once the code has been uploaded you will be able to interact with it using the USB-->serial adapter shown above, you have to connect the adapter to the Telemetry port on the OILPAN. To get into the CLI you will not have to switch the slider. This mode is disabled!

You need to use a Hyper Terminal to get to connect to the CLI the first time. This can be found in Windows XP in START-->All Programs-->Accessories-->Communications-->Hyper Terminal. For Windows7 and Vista you need to download the Hyper Terminal program from here:http://www.megaupload.com/?d=J31857IQ. This is the original Windows XP program.

So now that you have the USB-->Serial connected to the telemetry port and Hyper Terminal connected to the COM, power up the MP32 using for example the usb port on it. As soon as you connect you will see a message saying to press S to enter interactive mode. You have five seconds to press S after boot up. This will let you in the CLI mode. Use the the SETUP-->Reset to reset the parameters, configure your radio, level, calibrate ESC as you will do in old ATMEGA chip.

The ERASE function is not necessary.

Using the Planner to finish configuration

Once you have done first configuration, you will be able to connect to the MP32 using the AC2 planner found here

For all the rest you can use the the Arducopter Wiki which will guide you through the rest of the setup.


Frames supported by the code:

  • Quad X mode
  • Quad + mode
  • Hexa X mode
  • Hexa + mode


Features actually not supported by the code:

  • sonar is not implemented
  • camera mount stabilization is not working

All the rest should be working! This is still BETA so use at your own risk, and please report any issues to the Issues list in the Multipilot32 google code project.





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I can finally post a video of my quad. This is my 2nd FPV flight ever.

I was a bit nervous, but the latest AC2 firmware 2.0.39 proved to be rock solid!
Weather conditions were the best ever so I couldn't miss a 7 o'clock flight... :)

Nothing special in the footage apart the stability of the quad that needed only little tuning.
Here are my specs:

  • Arducopter center frame with custom ALU arms. 50cm circa motor to motor.
  • motors KDA 2022-L with 10x4.7 APC props
  • AC2 KIT with APM 2560 + mag + GPS
  • firmware 2.0.39
  • PIDS: 
  1. Stab. KP Roll-Pitch 3.5 
  2.  Rate KP Roll Pitch 0.11
  3. I defaults
  4. YAW defaults
  • GOPRO HD with no vibration dampening at all. Video footage only cutted on boring parts.
  • FPV gear RC305 5.8GHz RX (cheap china) + 200mW TX
  • Fatshark Base
  • a lot of adrenaline and may batteries of testing before FPV.... ;)



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