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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  • For power i would like to know how did you power it?i have to power all this:
    1.3ghz 500mw 5v transmitter;
    5v camera;
    the Ardupilot and expansion bord;
    Remzibi´s OSD and GPS

    so can i put some of this together like one battery for the transmiter+camera and another one for the Ardupilot+OSD+ GPS. What size should be the batterys for this? 2000mAh is ok? My aeroplane is a Senior Telemaster with 2400mm wing span and a 26cc gasoline engine. I can get 30 minuts of fligth with a single tank.
  • Hello to all i´m new on this subject - autopilot´s - and i would like to have your suport to assemble my Ardupilot. So far i have buy the ardupilot bord, the expansion board ("Shield") and the FTDI cable for programming. I´m going to buy also the Remzibi OSD with the GPS so i dont need to buy another GPS for the autopilot correct?
  • Thanks for the reply... real weird problem hey, might be the GPS is buggered - its been around the block a few times ;)
    When booting the LED shows dim but only for a split second, sometimes ill get a solid blue light right after boot and auto doesnt respond nor does the motor power up.

    Regardless I flew today without gps and the easystar loitered very reliably! :)
    I even took some nice full HD video :)
    Ill post it up here soon.

    Going to try another GPS and see if I can replicate the problem when I get motivated again hehe, thanks again for the answer about the LED! :)
  • I am having a similar problem with getting a GPS lock. I have the EM406 GPS and I have the GPS protocol set to 1. The red light on the GPS is very very dim, and the blue LED on the shield board is flashing away trying to get a lock.

    I've checked for bent pins and doubled checked the bind plug to make sure its correctly placed on the board. am i just waiting for a GPS satellite to orbit over?

    My question about the 4ch RC controller, thats not a big issue I can just burrow my friend's 6ch controller.
  • 3D Robotics
    Yes, the red LED on the 406 should be on super faintly (you have to cup your hands around it to see it). That means it's in digital mode, which is what's required. If you set your config file for SiRF and you're not seeing that, check to see if you've got a bent pin in the connector.
  • >Max
    the led on the EM406 should be on all the time (very dull)
  • @Aaron: you need a 6 channel Tx to switch ArduPilot in a different mode. You won't get far with your 4ch controller.
  • Hey quick question - having problems getting a GPS lock, its worked once only tonight and that was when I was inside!? The rest of the times the plane has been on the garage roof and wont get a lock :(

    Ok so all I wanna know is if the red LED on the GPS module itself should be very dull or be off all together?
    When I boot up or reset the ardu I notice the red led lights up very dull for a second but then it turns off - I forgot to look if it was on or off when it worked that one time... grr

    Yeah weird, I checked the gps cable and its ok... its the 406gps too btw - so if anyone could help me out that would be great!! :)

  • Have a question, I am working on a UAV for a school project and the plane I have for the platform is the Cessna 182 complete kit. It came with a 4ch controller and the plane has a 6ch receiver. I wanted to know how can I have the autopilot be switch on and off to give me the ability to have manual control of the plane? I read the instruction manual and it says to use channel 5 and 6 (remember I only got 4 channels on the controller) to be used as switching on the Ardupilot. I've looked through all the source code and I understand most of it, where an external interrupt occurs the autopilot knows what to do.

    I just want to know if I need a 6channel controller to be able to toggle the autopilot or can I do it with the 4channel controller that the plane came with?
  • Buying the (poor man osd + ardupilot) is enough to have the return to home feature (loss of rc control)? Or it needs more than that?
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