[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: 305360

Comment by fefenin on August 25, 2009 at 3:39pm

thank's for the explain , i understand now why we have to reset the integrator for every wp

and sorry about the:
byte wp_number=3;

i don't want any of us to be confuse but i wasn't sure about it...

looks like you've got a huge experience in long path flying,
i wish i could meet you and see your setup...but looks like we live in differnt country , a bit far away from each others.

thanks for all the tips in here

Comment by Doug Weibel on August 25, 2009 at 4:18pm

I see you looking at implementing the integrator. I think you might want to consider implementing a cross track error proportional component instead (or in addition). I suspect that it may be more effective and wouldn't be much harder to implement. If I were to the point of being ready to fool around with the code that is the direction I'd go. Unfortunately work has me so busy....

Seems like you could compute cross track error easily if you hold on to the original desired heading right after switching waypoints. With the current desired heading, original desired heading and distance to waypoint it should just be one cosine operation.

Comment by Doug Weibel on August 25, 2009 at 6:47pm

I tried my first code upload tonight and can't get it to work

I have the new red board. I tried to upload the code both with the shield on and off - same results.

I am powering the board with a NiMH 4.8 volt pack thru my RC receiver.

I have the DIYDrones FTDI cable. I hook it up with the black wire on the pin closest the gps connector.

I am using Arduino 0016. I have the comm port set to comm 5. I set the board to a duemilanovoe w/ ATmega328.

When I first power on the board I get the power light on and the Stat and Lock lights flash continually in a sequence (2 slow flashes in sequence, then 2 fast flashes in sequence, then on together for a second, then repeat).

When I plug in the FTDI cable I get occasional flashes on the Mux and Mode lights.

I checked the Set RTS on close box on the comm port properties. I have tried 9600 baud and 19,200.

The drivers I have on the comm 5 port are ftser2k.sys, serenum.sys, and ftserui.dll

When I try to upload code I get:

stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
Comment by Brent West on August 25, 2009 at 8:28pm
Are you unplugging the GPS? I'm still having to do that to upload.

3D Robotics
Comment by Chris Anderson on August 25, 2009 at 9:31pm

Those are the correct LED signals for a board from the factory. The serial speed doesn't matter (it's not used here).

Have you run through ALL of the tips in our debugging guide?

If you're still having trouble try it on another PC. You may have a driver issue.

Comment by Jordi Muñoz on August 26, 2009 at 12:19pm

Yes i will consider the Cross Track error. But is not a 15 mins implementation.

Comment by Jordi Muñoz on August 26, 2009 at 12:24pm
Spektrum Radios have a u.fl connector inside. You can buy an U.FL to SMA converter and a high gain antenna. Also you can add a 20 watts amps for 2500 bucks. =) Are also 50 watts available if you want to see what Chinese are doing.
Comment by Earl on August 26, 2009 at 4:04pm
Look at the ATV (Amateur Television) if you are looking for reasonable priced 2.4Ghz amps.
PS I got in 8 flights today.
Comment by Peter Meister on August 26, 2009 at 5:58pm
Way to go Earl!!! Today - I planned a 1 mile - 5 waypoint route with the latest config tool. Man it is flawless. Will post video later tonight. Plane flew like a champ, its kind of getting too easy now. Just load the mission, and go. Its really drop, click and fly now!!!

Comment by Mark Colwell on August 26, 2009 at 6:18pm
I was able to get Ublox connected and working with Jordi's great interface board. Then I needed to reverse IR sensor pitch output, Then tuned servo centers and end points, and completed two IR stabilized flights. Horay!! now I will attempt a Waypoint test flight in morning and hope to enter DIY T3 race tomorrow, but I don't know how to get a GPS track with ground station running , I am capturing a text file with Hyper terminal. I can only run 1 or the other, Any suggestions ? Thanks


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