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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  • I have been busy trouble shooting the xbee's but got similar results as above. However after some fiddling with the Ardupilot (I removed the shield) powered up the Xbee through Ardupilot and tried X-CTU and Arduino serial monitor. X-CTU gave red "bad data" but Arduine simply showed me in black. I restarted ground station and reset to original values, retyped the COM4 and baud rate and tried "run" again and dials started moving and LAT & LON were showing actuals values. Problem solved!

    The only thing I did not get to work was the real time display in Google Earth Anybody knows where I can find some info on that. The Ardupilot is listed in the menu on the left. Do I need to instruct Google Earth to show the plane??

    So I think I will be ordering a new Shield to replace the faulty old one on which I did not get the GPS to work on and try to get some test flight soon. Thanks for all the help
  • Developer
    @JvdB - It is very strange that the literal text portions of the transmission come through correctly (e.g.!!!LAT:) but the variable data does not. I don't see how the xBees could foul up just those portions of the serial data stream.

    What do you get if you hook up your FTDI cable instead of the xBee and use the Arduino Serial Monitor?
  • Have anyone tried out a V tail plane for ardupilot?
  • well done!

    "bravo" , looks like you can now try to win the T3 contest
  • Developer

    Despite too many hours a week spent working and too many projects competing for my attention during my free time....

    My complete ArduPilot system flew a successful mission today! I have the Ardupilot, shield, EM406 combination mounted in a SuperStar with a brushless power conversion. I am using 2.4 Ghz Xbee Pros with ArduStation running on a laptop. Everything worked properly - manual mode, RTL, waypoint mode, downlink, and ground station. Flew several laps around a 6 turnpoint mission. I even put the SuperStar in an upside down attitude and then engaged the autopilot. No problem. I need to do some tuning of the config file for the airframe, but after weeks and weeks of fighting little things it is very nice to get my first drone working!

    Thanks for everyone's patience and assistance.
  • thank's jordi for this add on!

    just about something else...
    does someone in DIY drones ever tried the - Vectornav VN-100 ahrs ??
    if yes what are your impressions?

    i guess it could be a wonderfull imu to add to ardupilot + Ublox ...

    thinking to buy one of those to get a very reliable IMU on a 1/4 benzin heli

    any help or thinking is appreciated


  • Developer
    Also you can connect you uBlox to the PC directly using your FTDI cable, fallow this:
    uBlox IN -> Orange Wire
    uBlox OUT-> Yellow Wire
    uBlox + -> Red Wire
    uBlox GND-> Black Wire

    Then use uCenter to debug...
  • Problems solved guys. Thanks for all the support. I tried Jordi's approach and although it sounds like something one could think of yourself it actually did the trick. I removed the shield, inserted the GPS in the Ardupilot and within 1min (45s actually) I got a firm GPS lock. Note: the stat and blue LED were not flashing at all until the blue LED turned solid and at the same time the stat started flashing at 1Hz. Slightly puzzled I tried the old config (now I knew the cable, adapter and GPS were just fine and the GPS acquired a lock) and same old story: flashing blue LED but no lock. Do you know if it is a bad soldering job or is it a faulty female EM406 connector / board?

    Anyway, now I use the Ardupilot for the GPS and plugged the shield on top. The LEDs are copied so I can still fly with the shield but I guess I will need to unplug the GPS everytime if I want to upload new code.

    For know I will have a cold beer and see if I can find some more time tomorrow. Tnx!
  • JvdB,

    to use U-center and check out every thing you will have to canibalized one of the cable you use to plug the GPS (i did it with the short one)

    you will have to cut one of the plug (one end) and solder that the right way to a header that fits the FTDI

    when i did that for me i used the FTDI 5v to power my Ublox but i guess now FTDI cables ar giving only 3.3V so you'll have to power it by something else (maybe USB directly)

    so here is what to do again:


    1 DTR X nc
    2 RXI 3 TXO
    3 TXO 4 RXI
    4 3.3V or 5V if 3.3V then find a 5v source. if 5V then connect to pin2 : VCC
    5 CTS X nc
    6 GND if 3.3V then find a 5v GND . if 5V then connect to pin5 : GND2

    i'm not responsible for any dammage, you should check that up before powering it up!

    it works great for me but again i used the FTDI 5V

    after that you can see every thing inside the UBLOX center witch sentence is set how etc....

    good luck

  • Developer

    I still suggest hold it very well with hot glue between the boards, is the only way you can keep it perfectly horizontal. That tiny connector is very weak and fragile, is awful.

    Try to connect the GPS directly to the ardupilot board (not the shield)
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