3D Robotics

ArduPilot (Legacy) main page




[This original ArduPilot board, now called the "Legacy ArduPilot" is no longer produced or officially supported by the DIY Drones dev team, and this page is maintained just for historic reasons. However, there are still many users of it out there and it still works fine. The user group for Legacy ArduPilot users, for both thermopile and IMU use, is here.]


ArduPilot is a full-featured autopilot based on the Arduino open-source hardware platform. It uses infrared (thermopile) sensors or an IMU for stabilization and GPS for navigation. It is the autopilot used to win the 2009 Sparkfun Autonomous Vehicle Competition.

The hardware is available from Sparkfun for $24.95. An expansion board ("Shield") kits that includes an airspeed sensor, a 3.3v power regulator for 3.3v GPS modules and other sensors and cables and connectors for easy attachment of the XY and Z sensors, is available from our own store for $57.20.


User f

ArduPilot features include:

  • Can be used for an autonomous aircraft, car or boat.
  • Built-in hardware failsafe that uses a separate circuit (multiplexer chip and ATTiny processor) to transfer control from the RC system to the autopilot and back again. Includes ability to reboot the main processor in mid-flight.
  • Multiple 3D waypoints (limited only by memory)
  • Altitude controlled with the elevator and throttle
  • Comes with a 6-pin GPS connector for the 4Hz uBlox5 or 1hz EM406 GPS modules.
  • Has six spare analog inputs (with ADC on each) and six spare digital input/outputs to add additional sensors
  • Supports addition of wireless modules for real-time telemetry
  • Based on a 16MhZ Atmega328 processor. Total onboard processing power aprox 24 MIPS.
  • Very small: 30mm x 47mm
  • Can be powered by either the RC receiver or a separate battery
  • Four RC-in channels (plus the autopilot on/off channel) can be processed by the autopilot. Autopilot can also control four channels out.
  • LEDs for power, failsafe (on/off), status and GPS (satellite lock).


ArduPilot requires the free Arduino IDE to edit and upload the code to the ArduPilot board.

The code is currently optimized for the Mutiplex EasyStar three-channel powered glider and FMA sensors, but can be modified for other aircraft and sensors. It uses the rudder/ailerons and elevator to maintain level flight and navigate to GPS waypoints. It supports a desktop setup utility and ground station software. It also includes a "fly-by-wire" mode that simply stabilizes RC flight. The main code is ArduPilot2.x.zip in the download section of our Google Code repository, where x is the latest version.

What you need to make a fully-functional autopilot:

Open source extras:

  • If you want to build your own board from scratch, the necessary files and component lists are here.
  • [Note: you shouldn't need this, since this code is loaded on the ArduPilot board at the factory] Latest multiplexer code (for the board's second processor, an Attiny, which runs the failsafe system) is here.
    Instructions for loading this code are here.

Recommended UAV setup:


Airframe option one: Hobbico SuperStar (49" wingspan, $95, shown above). This is an inexpensive, good flying high-wing trainer with ailerons. It can be hand launched in a park or take off from a runway, and replacement parts are readily available in case of a crash. If you want much better performance with this aircraft, you can upgrade it to a brushless motor, speed controller and a LiPo battery. [If you don't already have one, you'll also need a balancing charger and power supply.] Note: any stable aircraft with both ailerons (for stabilization) and rudder (for navigation) can work, so feel free to experiment with what you've got.


Airframe option two (recommended for ArduPilot 2.x): EasyStar (shown above). Performance can be improved with the modifications described in this post.

You'll also need:

  • A six or seven channel RC transmitter and receiver, with at least one toggle switch (ideally three-position but two-position will work, too, although you will have to mix channels to have access to both autopilot modes in the air), such as the Futaba 7C.
  • Some servos (at least three for ArduPilot 1.0; at least two for ArduPilot 2.x) and at least three female-to-female servo cables to connect the RC receiver to ArduPilot.

Cool optional extras for your UAV:

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  • Thank you for your help but i think i don't have all things clear.
    I have an Ardupilot board, Locosys LS20033 GPS receiver and FMA Co-pilot on a composite power sailplane and want to use them as a RTL device when rc signal is lost or when i want it to and as a waypoint devise too.
    Any help to set up everything is welcome.
    I have tried different things without success so i am starting over.
    I have already installed Arduino 18 and Code 2.6.1.
  • @Theodoros

    Sorry I did not reply until now. Perhaps you can use the reply button and your messages will show up in my page.

    Anyhow, you sound like you're on your way. You may want to do some simple testing first without any speed control. Here is my suggestion:

    Let Co-Pilot control your ailerons and elevator - this will give you stability. Of course, you can take back manual control at any time by flipping your gear switch. This leaves Rudder and Throttle. For now, I would suggest leaving the throttle directly connected and only use the Ardupilot for Rudder. You can use Ardpilot 2.3 and make sure to set "walkaround mode" to 1 (let me know ifyou need help setting this up).

    This way you will have a stable aircraft and it should navigate to waypoints. You will need to manually nudge the elevator to keep your height and control your speed.

    Once you get satisfactory results you can disconnect the elevator from Co-pilot and connect it to Ardupilot. Also, you can connect the throttle to Ardupilot. Your setup will now be:

    Co-pilot > Ailerons
    Ardupilot > Rudder, Elevator, Throttle

    At this point you can use the latest version of the code (2.6). You may need to add an ArduIMU to complete the system (this is for attitude sensing)

    I really hope this helps.

    I'm testing a similar setup but I'm using Co-pilot for stability and ArduIMU for attitude readings with telemetry.

    Do let us know how you get along!
  • Hi to all,
    I am configuring my ardupilot but i have a question.
    Is it normal for the rudder and motor to run for three short times during start up?
    Thank you
  • 3D Robotics
    @Tommy. Yes, the ArduPilot GCS automatically datalogs everything and can output KML.
  • Hi space nut.
    Everything just arrived.
    I have already soldered the FTDI pins, the power pins three servo in pins, two servo out pins, one GPS Rx and one GRD pins and two pins om D6 and D7 for the Home position Jumper.
    I downloaded the FTDI Drivers and i am ready to go. It will be in a power sailplane with ailerons. Stabilization (elevator, ailerons)will be controlled via FMA Copilot CD4 (like you suggested) and navigation (rudder, throttle) will be via Ardupilot.
    Any ideas which version i need to upload for the ardupilot to work with rudder and throttle.?.
  • Hi Chris,
    If I want to save one additional GPS logger on the plane for geotagged the aerial photos, can I save the tracklog via Xbee and ArduPilot GCS? Thanks.
  • NP.

    Look forward to hearing about your progress.
  • Ok then that is what i am going to try to do.
    Can´t thank you enough.
  • In most versions of the code there is a header file. You make all your adjustments there e.g. there is a setting for shield version - just set that to -1 for "no shield". Another setting is airspeed sensor - you can configure for no sensor.

    Since you have ailerons, you may want to use a "combo" setup where you have a full FMA Co-pilot (or a second Ardupilot) controlling your stabilization (Aileron and Elevator), then use the Ardupilot for Rudder and Throttle. There is an older version of Ardupilot (2.3 which allows you to select "walkaround mode" which puts your Ardupilot into the required mode.

    I'm pretty sure that you will not be able to get all your control surfaces working with one Ardupilot. That's in the works for the Ardupilot Mega but the code is still being developed.

    So I think your best bet is the FMA Co-pilot + Ardupilot. Cost of XY sensor is $40, Cost of Co-pilot (including XY sensor) is $65 - not a bad deal.
  • Can anyone show me to the code needed to be uploaded so i can have FMA sensor and throttle control without Shield?.
    I mean space nut showed me how to hook up the sensors (Thank you) but the link states that it is the version that controls altitude with elevator. I am using a composite glider and need ailerons and elevator for stabilization and navigation and throttle for RTL.
    Please bare with my ignorance.
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