DROPIX Flight Controller
Author: Vincent JULIE
Version:2.1
En date du :06 Aug 2016

First Configuration

dropix

This product contains:

1. Autopilot Hardware licenced under the Open Source Hardware License OSHW 1.1 definition licensed under the Creative Commons Attribution-Share Alike 3.0 Unported (CC BY-SA 3.0) license. <https://github.com/PX4/Hardware>

2. Autopilot Software licensed under the GNU General Public License Version 3 as published bythe Free Software Foundation. <http://www.gnu.org/licenses/>and is copyright (c) Ardupilot developer team. All rights reserved. Please see <http://firmware.diydrones.com/ >

  • THIS PROGRAM IS DISTRIBUTED IN THE HOPE THAT IT WILL BE USEFUL, BUT WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

3. Autopilot Software licensed under a permissive 3-clause BSD license. Copyright (c) PX4 Development Team. All rights reserved. Please see <https://github.com/PX4/Firmware/blob/master/LICENSE.md>

  • THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

For further information please see <https://www.dronecode.org/>

Mission Planner installation

MissionPlanner is a ground control station for APM Aircraft, Helicopter APM and APM Rover.

It is compatible with Windows only. MissionPlanner can be used as a configuration utility or as a dynamic interface for your self flights.

The installer of Mission Planner is available here.

-> Download this file to your computer.

-> Open the installation file:

MP-install Mission planner latest

The wizard will install Mission Planner for you on your PC. Installation is immediate and does not require drivers.

MissionPlanner is now installed and ready to use on your computer. An icon to start the program was created.

MP-icon

For more information, we recommend you click here.

Firmware update

First, check that you have inserted a micro SD card into the port provided for this purpose on the Dropix. (Otherwise it will not work!)

It may be that the firmware to be updated, in this case just start MissionPlanner, and go to “Initial Setup”, “Install Firmware” and then choose the type of system you have, here we will use a quadricopter.

Setp-1-MP-update-firmware1

You can see this link which explains how to update the firmware to the Dropix.

If you have problems connecting to MissionPlanner, you can refer to the troubleshooting section here or on our forum.

Step by Step Wizard

The wizard is an easy way to configure a multirotor quickly. First, select the shape of your frame. For this, start Mission Planner and go to the “Initial Setup” , then select “Wizard”.

Setp2-Wizard-clic

Once done, you should get the following screen:

Step3-Wizard

Select “Multirotor” and click “Next >>”.

Then you should choose the actual shape of your frame:

frame

x,+ or more atypical forms.

Accelerometer Calibration

To fly properly, the drone needs its “0” position. Therefore calibration is essential.

First, get a bubble level for optimum accuracy.

We see now this window:

calib-accelero

Simply start the calibration by clicking START, then the tutorial will ask to turn the drone in 6 positions:

-at Level

-Left side

-Right side

-Nose down

-Nose up

-On the back

calib-acc

 

“Calibration succesfull” should appear.

Magnetometer Calibration

It is important to calibrate your magnetometer to enable the drone to be more specific flight (loiter Mode, Mission ..). The metal on drone modifies the magnetic field received by the sensor. Without calibration, this one will be hard to make a clean signal and find the direction of the drone.

The Wizard proposes the following calculation:

calib-mag1

Once you have clicked “OK”, you will handle your drone in every way, in all directions. In an attempt to reach the white dots in the ball(s). (See below)

mag-calib-2

Each of these balls is the representation of a magnetometer.

Here we use the one on the dropix (left) and that of our GPS uBlox + hmc (right).

Namely one mag enough to fly. But the interest to equip 2 is explained here: Mag and motor calibration

Once is done,  the next is here : Power Module

If you have one, click the link above, otherwise skip this step and go to Sonar I²C. Again if you do not have sonar, skip the step

Radio Calibration

Here we will configure your extremums radio signals. So we start the calibration, make sure you have the receiver connected and powered, also prepare your radio. Click the buttons in the order below:

calib-radio

Now you have to move your sticks in their maximum positions and in all directions. It is also an opportunity to see if you do not have inverted signals. As soon as the little red marks are the maximums, validate. Before clicking on “2”, make sure you have centered all the sticks, and keep the Throttle minimum.

calib-radio-2-1024x499

Your Radio is well calibrated!

Fail Safe

This is a very important part of configuring your multirotor. In fact the latter will allow the drone of what to do in case of failure.The Fail Safe is a system status. This is a security mode that is activated in case of problems. It allows the UAV to perform emergency maneuvers or send sound alerts in case of fall.There are several choices to define your modes.

failsafe-menu

Battery:

The battery voltage fall moderately during the flight and quickly towards the end, which is surprising. This is why it is important to set this parameter. You can set a fashion Land or RTL.

Tip: To find out what voltage to take the number of battery cells and made x3,2.

Example: 4S -> 4×3,2 = 12.8. 6S-> 6×3,2 = 19,2. For 4S, set minimum 12.8 Volts for the 6S, choose 19.2.

Radio:

If the drone moves away and loses the radio signal, it can activate the failsafe and order 3 choices: Land, RTL or “continue the Mission”. And finally some specific cases, if you use the GCS (MissionPlanner) to control your drone with a joystick for example, you can also declare a failsafe in case of non receipt of more than 5 seconds receiver.

GEOFENCE

The geofence is used to set limits to the drone flight. This creates using a GPS a cylinder. And the drone will not cross it.

geofence-e1437488983858

The geofence is configurable in the wizard:

Geofencescreen

more informations : Geofence

First Flight

Flight Mode

Stabilize Mode

We invite you to read this page.

RTL Mode

We invite you to read this page.

Land Mode

We invite you to read this page.

Pre Arm check

I invite you to read this page.

Arming / Desarming

We invite you to read this page.

DROPIX Setup

The Dropix has a default orientation indicated on the box and on the card itself. It shows the front of your vehicle.

dropix-forward-boitier

forward-dropix

The DroPix has 3 different power inputs. This redundancy may be useful in case of power failure on the part of equipment.

However, it is not mandatory for all connected, one is enough.

The sources:

You can feed it by BEC (5V to 6V) on the rail motors and servos (No. 1 to No. 5A).

moteurs-output

You can also go through the power module, it connects as shown below.

POWER-MODULE1

And of course by the USB port.Note that these supplies can be used simultaneously without any problems.

Important : Dropix must have an SD card to be able to boot.

Inputs / Outputs

This is the pin map of the dropix.

DroPixV2-TOP

PINMAP-DROPIX

ESC / Motor

ESCs have to be connected to the “MAIN OUPUT” of the Dropix between 1 and 8.
ESCmotor

Each ESC must be completely connected to the output reserved for it. For this you just need to look at the next picture and choose the drone model you want to use.

For example the motor 1 must be connected to the output n ° 1 of the Dropix. Then 2 to 2. Ditto for all other motors.

motors

All blue motors should only be used with CCW propellers. Green motors with propellers CW.

To identify what does a CCW/CW propeller, please see the previous photo.

 

Also check the direction of the motors. For safety reasons, remove the propeller before handling !!!!!! To reverse the direction of a motor simply reverse 2 of the 3 cables that go from the motor to the ESC.

Safety switch

Here is the push button, it is used to arm the drone manually. Indispensable from the Dropix V2.

BPcover

The wiring is as follows:

Namely in reality the 3 cables are black, just try one way and then the other, and when the LED is blinking, the right choice. (No risk of short circuit).

BPwiring

 

bouton-poussoir-meanings

Buzzer

The polyphonic buzzer is used to inform the system status, such as LEDs, but with different sounds. Where to plug:

buzzer-poly-wiring1

You can listen all tunes on this site.

LED Module

Here the LED module for Dropix:

Led-dropikche

It provides information on the state of the system via various mixtures of colors and flashes.

LEd-meanings22-2

How to plug:

LED-connecting

Power Supply

Voltage & current sensor board

pp1

This module can measure the battery voltage and current consumption with effect Hall sensor. It’s compatible with Dropix and Pixhawk flight controller.

capteur-de-tension-courant-a-effet-hall

The setting for measuring current / voltage in Mission Planner:

In “Initial Setup”, select “Battery Monitor” and change the values:

Monitor : Voltage and Current

Sensor : Other

APM Ver : Pixhawk

Voltage Divider : 15,55

Amper per volt : 151,5

 

PM

 Don’t forget to change the “BATT_AMP_OFFSET” parameter.

PM21

You can check all information in real time in the “Flight Data” page.

PowerModule2

Power Module Pro

MDP_Dropix1

This power supply module provides power to your Dropix flight controller and your FPV equipment with a clean and stable power from your battery.

With 2 * 5V outputs, it offers redundant power for your flight controller.
This module is capable of measuring the battery voltage and the overall consumption of your system.

It is equipped with protection against surges on each regulated output as well as a protection against inrush currents during battery connection (anti spark).

Each controller is equipped with a LED indicator to ensure proper operation of the power board.

module-de-puissance-5v-12v-capteur-tension-courant-1

Entree_TOP

The setting for measuring current / voltage in Mission Planner:

In “Initial Setup”, select “Battery Monitor” and change the values:

Monitor : Voltage and Current

Sensor : Other

APM Ver : Pixhawk

Voltage Divider : 15.7

Amper per volt : 54.6

(note: most current sensors are not very accurate at low currents (less than 3Amps). Typically you should perform current calibration at around 10A)

Drotek-Power-Module

PowerModule2-1

 

Radio receiver

There are 3 different ways to connect your receiver to the Dropix all depends on your hardware.

Classic Receiver: If you have a conventional receiver you must go through a PPM encoder (up to 8 CHANNELS). Remember to activate the solder bridge on the encoder if you want to power your receiver from the Dropix.

PPM-receiver

SBUS receiver: If you have a SBUS receiver, as “X8R” of FrSky, you must pulg on the output RC of the Dropix

Spektrum Satellite: as with the PPM, all channels go through one cable. For receivers Spektrum DSM, DSM2 or DSM-X Satellite RC, log on Spekt port Dropix.

Optionnal Hardware

Airspeed sensor

airspeed_dropix

Plane supports the use of an airspeed sensor, which can help in windy condition, slow flight and autonomous landings. It is not recommended for most new users, however, as it does require additional tuning and adds one more layer of control to set up.

The following sections show how to wire sensors to the flight controller.

digital-differential-airspeed-sensor-kit-

A digital airspeed sensor is available  from drotek.com. Connect the airspeed sensor to Dropix or Pixhawk’s I2C port (or I2C splitter module). Using the rubber tubing, connect the longer extension on the pitot tube to the cone that protrudes from the top of the airspeed sensor board (off the off-white, square section protruding off the top of the board), and connect the shorter extension on the pitot tube to the cone protruding from the base of the board.

Software confirguration

You need to enable the airspeed sensor in Mission Planner | InitialSetup | Optional Hardware | Airspeed.

airspeed-drotek-dropix

Note:

Oscillation between zero and small values (2-3) is normal. The airspeed varies with the square root of the pressure, so for differential pressures near zero it varies quite a bit with very small pressure changes, while at flying speeds it takes much greater pressure changes to produce a similar change in speed. If you see mostly 0, 1, 2, with an occasional bounce to 3 or 4, consider it normal. You will not see that sort of variability at flying speeds. As a check, you can take the fleshy part of your fingertip and press it against the pitot tube to raise the airspeed reading up to say 15 m/s. It is easy to see that holding a significant constant differential pressure like this the reading does not bounce around (if you keep constant pressure).

airspeed-drotek-dropix-pixhawk

Once you have the airspeed sensor connected, you can use it to control aircraft speed in auto modes. Change the “Cruise” setting in the  Basic Tuning screen of  Mission Planner:

airspeed-dropix

 

Pitot tube installation

When you place the airspeed sensor in your aircraft, use the pitot tube set in the kit (the kit comes with a single tube to measure both static and total pressure). Make sure the holes in the side of the tube are not covered. They should be at least 1 centimeter out past the nose. First connect the two tubes coming out the back to the airspeed sensor. The tube coming straight out the back should go into the top port and the tube exiting at an angle should connect to the bottom port on the airspeed sensor. Drill or cut a small hole in the foam and push it through to the front.

 

If you are using Plane in an aircraft with the propeller in the nose, the pitot tube must be mounted out on one wing, at least a foot from the fuselage to be outside the prop flow.

Calibration

The airspeed sensor reading is automatically zeroed by the APM during initialisation, so it is good practice during windy conditions to place a loose fitting cover over the pitot tube that shields the front hole and the four small side holes from the wind. This cover should be fitted prior to power on and removed before flight. If you forget to do this, you can always place the cover and repeat the airspeed auto-zero using the Mission Planners PREFLIGHT_CALIBRATE => Do Action.

The airspeed reading scale factor is adjusted using the ARSPD_RATIO parameter. Plane has an automatic calibration function that will adjust the value of ARSPD_RATIO automatically provided the plane is flown with frequent direction changes. A normal model flying field circuit pattern or loiter will achieve the required direction changes, cross-country flying will not. To enable automatic airspeed sensor calibration, set the value of ARSPD_AUTOCAL to 1.

All In One Module

Led_Dropix_2

All-in-One module integrates the buzzer, the safety switch, USB port and LED indicator. This provides a cleaner installation on your drone and thus simplifies integration.

The module allows you to configure the Dropix via an external USB. This becomes essential when the flight controller is hidden in your drone.

You can find the name of each input/output of the connectors on the picture below.

Led_Dropix_4

GPS

Mushroom GPS

This module embeds a GPS chip (NEO-M8N uBlox) and a magnetometer (HMC5983) for the computation of the position and orientation of your system.

The first picture below shows the connection between the GPS “mushroom” and Dropix. The second photo shows the orientation relative to each other (follow the arrows on the boxes).

 

ublox_mushroom

Once everything is connected and in place, you must configure the GPS in “Compass” menu like the picture below. Don’t forget to select “ROTATION_ROLL_180“.

Drotek-Ublox-Mushroom

Then click the “Live Calibration” button and turn your drone in all directions for a few seconds to complete the two spheres. This procedure will allow you to calibrate the compass.

mag-calib-2-1

A message will appear to warn that calibration is complete. The data will be saved automatically in the Dropix.

How to install the GPS:

  • Place the module on the outside of the chassis, if possible, with a good “view” of the sky, as far as possible the motors and ESCs and in the correct orientation.
  • Keep away from sources of supplies. The use of a mast is highly recommended.
  • Keep remote unit from metallic objects. (Prefer nylon or nonmagnetic steel / aluminum).
  • When possible, twist all wires.

Ublox XL GPS

This module embeds a GPS chip (NEO-M8N uBlox) and a magnetometer (HMC5983) for the computation of the position and orientation of your system.

The first picture below shows the connection between the GPS  and Dropix. The second photo shows the orientation relative to each other (follow the arrows on the boxes).

UBLOX_XL_2

Once everything is connected and in place, you must configure the GPS in “Compass” menu like the picture below.

Drotek-Ublox-M8N1

Then click the “Live Calibration” button and turn your drone in all directions for a few seconds to complete the two spheres. This procedure will allow you to calibrate the compass.

mag-calib-2-2

A message will appear to warn that calibration is complete. The data will be saved automatically in the Dropix.

How to install the GPS:

  • Place the module on the outside of the chassis, if possible, with a good “view” of the sky, as far as possible the motors and ESCs and in the correct orientation.
  • Keep away from sources of supplies. The use of a mast is highly recommended.
  • Keep remote unit from metallic objects. (Prefer nylon or nonmagnetic steel / aluminum).
  • When possible, twist all wires.

Rangefinders

Maxbotix I2C Sonar

Sonar is a sensor which measures the distance between the ground and the drone. This provides greater accuracy of altitude in relation to the use of a barometer.

The MB1242 sensor presented below is capable of measuring a distance between 0-7 meters. It is available here.

Connect as below:

DroPixV2-Sonar

The second step is the configuration in Mission Planner. Update the values defined below and click on “Write” to save settings in memory of Dropix.

  • RNGFND_MAX_CM = “700” (i.e. 7m max range)
  • RNGFND_TYPE = “4” (PX4-MaxbotixI2C sonar)

Just for information, the flight controller uses data from the barometer when the height of the drone exceed 4.60 meters. Below this height the sonar takes over and increases the accuracy during takeoff, flight and atterrisage low altitude.

Top-page

Test sonar sensor :

The distance read by the sonar is displayed in the variable “sonarrange” in the below tab.

sonar

 

PX4Flow

in contruction …

PX4flow

Telemetry kit

The telemetry kit is used to keep a wireless connection between Dropix and the ground station (MissionPlanner). You can receive real-time data flowing in the drone and even change the PIDs in flight.

Communication baudrate is  433Mhz or 915Mhz.

How to plug :

telem-wiring

Configuration :

Connect the “ground module” (with USB port) on the computer or the air module on your Dropix. In the second case, connect to the flight controller.

Select top right COM port and baud rate 57600 for the ground, and the Dropix at 115200 for air.

Go >> Initial Setup>> Optional Hardware >> 3DR Radio

Click “Load settings”

3DR

You can change the values to increase your reach or communicate faster.

You can change the values to increase your reach or communicate faster.

Net ID: This is the channel that will provide radio, 2 must have the same value.

Tx Power: The power tenfold by radio for data transmission. Can be increased to increase the range.

Air Speed : cruising speed data through the air. Can be reduced to increase the range.

Baud : Communication speed of telemetry. Can be decreased to increase the range.

Antennas:

Contrary to what one might think, the antennas pointing towards one another is not recommended.

The diagram below shows the spread of the air waves, here pointed upward.

disturbedMonopole

There are different antennas adaptable to Telemetry as needed.The best model :

antenna

Link : Antenna – Drotek shop

Advanced Configurion

ESC calibration

Here you will see how simply calibrate your ESCs.

 

Above all, make sure you have removed your propellers.

– Completely unplug your drone.

– Turn on your radio and push the throttle to maximum.

– Connect your drone, and wait for the LED lights red / blue / green. (it will enter into calibration mode the next start)

– Disconnect the drone, the buzzer will inform that you armed. Press the safety switch on the drone.

– Lower your throttle suddenly to 0.

– The motors should sing and the calibration is complete. You can also test start simultaneously the motors by mounting the throttle.

Turn off everything and the next start will be normally.

Youtube video

 

Reduce vibrations

Here are some ideas to counter the vibrations with and without mission planner.

First of all you can evaluate your vibrations with a very simple test:

Take a flight with your drone (about 1 to 2 min ..) and go to the logs. [Go to the logs: Terminal / PX4 Connect / Download logs / Load logs, then return to the terminal and go to “browser logs”, select the log of your flight, and open it. Then go to “IMU” and check AccX and AccZ. AccX should be between -3 and +3 AccZ must be between -15 and -5 To counter this, you can use anti-vibration pads.

 

PAV

There are more ingenious solutions, I let you watch :

Vibration damping

Magnetometer / Motor calibration

The system is developed to work with two magnetometers. The “internal” mag is on the Dropix, “External” on the GPS. The first is used to measure the magnetic fields emitted by motor / ESCs then subtract to the one which is exported. There are 2 ways to measure your magnetic fields, with the throttle or the measure amperage from the battery.

/!\ Make sure you have removed the propeller before calibration /!\

The function starts motors without arming

Enable Power Module, put upside down your propellers. Attach the helicopter (perhaps with tape) so it does not move.

Turn on your transmitter and keep the throttle to zero. Connect the battery then connect your flight controller to your computer with the USB cable.

Open the Initial Setup >> Hardware >> Optional Compass / Motor Calib screen menu, then press start.

CompassCalibration_CompassMot-1024x627

For versions 3.1.5,

Start by going into the terminal, and select “Connect PX4”, wait a moment and type “setup”, enter, and “compassmot”

Then on your radio, turn up your throttle very gently from 0 to about 75%. then quickly back down to 0. your calibration is complete!

CompassMot11

Spektrum satellite

To use the Spektrum hardware, you need only connect the satellite (see photo below).

Here are the connections to make:

spektrum-wiring

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