[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:

Views: 305348

Comment by Jordi Muñoz on August 10, 2009 at 10:51am
You are welcome!
Comment by Brent West on August 10, 2009 at 9:12pm
Hi Jordi,
For the throttle adjustments in the header, what is the
#define throttle_dead_zone 20 //In porcent %) and the

#define throttle_absolute 3 //Absolute)

adjustments for?


Comment by Jordi Muñoz on August 10, 2009 at 10:12pm
Ok everybody is happy with the lasted code? The candidate release will have better comments and header organization. Please answer everybody.

Comment by Jordi Muñoz on August 10, 2009 at 10:14pm
The 3-23 is the Throttle Dead Zone. Used to eliminate the dead zone of your motor.

3-24 is the absolute value of the PI Control Loop. Normally is the P+I = Output to the servo, well the absolut is an extra, so i use Proportional, Integrator, Absolute controller. The absolute gain will be multiplied by the setpoint (Absolute * Setpoint) and added it to the PI output. WHYY?? Because you can not control the speed very well with only PI, is like the cruise control of you car. First you must know you car gas valve very well and when you say i want to travel at 60mph you must multiply that by the Absolute value in this example imagine is ".5" the absolute output will 30% of the gas range (100% is the maximum you can push you accelerator), then the PI control will try to maintain 60mph making small adjustment around the 30% of your accelerator travel. I do the same using airspeed and the desired airspeed. So you want to go 10m/s, so maybe i will have to run at 50% of the throttle and the PI will make small adjustments around the 50% of the throttle. Otherwise will overshoot at the beginning.
Comment by fefenin on August 11, 2009 at 2:29am
i had no time yet to try it at the field (neither on a boat or plane)
i'll try to do that today, but the walk around seems to give very good result so...

is there a way to control pulsout for CH4 from arduino board , with coding of course !

ailerons controls by stabilisation and rudder controlles by Nav , as the ardupilot 1.0 but with the stabilisation build in?

does that makes sense?

3D Robotics
Comment by Chris Anderson on August 11, 2009 at 6:55am
Fefenin, yes that's possible (with a lot of coding), but why? What's the advantage of moving those two functions to different control surfaces?
Comment by Brent West on August 11, 2009 at 10:56am
Supper explanation Jordi, thank you Sir.

Wish List: New instructions in the manual on how to use the “Debugging Stuff”.

Learned how to calibrate the servos by chance…. At one time, I saw the results of my sensor test, but now I’ll have to go way back to see how I did it.

Working on the final setup to the rigging of my aircraft, can’t wait to test it and report. The job and the heat here in Arizona is holding me back.

Looking forward to new flight test, by others.
Comment by fefenin on August 11, 2009 at 11:27am
i don't know i thaught it could be more stable for higher wind configuration but i'm not going do do it anyways was just a question...

i just went for a ride in my car with ardupilot set in walk mode.

it works great but at the end of the waypoint track it is going "HOME" (normal) and after reaching "H" it is going back to do the track is it normal???

if it is normal i suggest that you put a setup into the header to loop the waypoint (and last waypoint should be home) or just to turn around "home" forever...
Comment by space_nut on August 11, 2009 at 12:27pm
For those who would like to track their UAV/UAS on a laptop in the field, I'm going to try Microsoft Streets and Trips. It will accept input in raw NMEA 2.0 or higher. That way, you don't need to be hooked up to Google or the internet but you can follow your plane's path in real time and zoom to whatever level. You can also record the path. Will post some pics when I get it working..
Comment by space_nut on August 11, 2009 at 12:31pm
Has anyone developed a routine for the Ardupilot to CIRCLE a waypoint at the set height? That way, the UAV can just lurk there till you tell it to RTL


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