ArduPilot main page

Chris Anderson
DIY Drones

January 21, 2009

ArduPilot is a full-featured autopilot based on the Arduino open-source hardware platform. It uses infrared (thermopile) sensors for stabilization and GPS for navigation. It is the autopilot used to win the 2009 Sparkfun Autonomous Vehicle Competition [ http://bit.ly/DL8f0 ].

The hardware is available from Sparkfun for $24.95 [ http://www.sparkfun.com/commerce/product_info.php?products_id=8785 ]. 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 $47.50 [ http://store.diydrones.com/ProductDetails.asp?ProductCode=KT%2D0001%2D01 ].

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 (ArduPilot 2.0) or throttle (ArduPilot 1.0).
Comes with a 6-pin GPS connector for the 1hz EM406 GPS [ http://www.sparkfun.com/commerce/product_info.php?products_id=465 ] module. Faster 4-5hz GPS modules, such as the uBlox5 and Locosys 200031, are supported via the expansion board [ http://store.diydrones.com/ProductDetails.asp?ProductCode=KT%2D0001%2D01 ].
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).

The software comes in two varieties: 1.x (navigation-only, requires a third-party stabilization system for aircraft) and 2.x (navigation and stabilization integrated into one).

Both require the free Arduino IDE [ http://arduino.cc/en/Main/Software ] to edit and upload the code to the Ardupilot board.

ArduPilot 2.x, the navigation+ stabilization version, is currently optimized for the Mutiplex EasyStar [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFRU7&P=ML ] 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 [ http://code.google.com/p/ardupilot/ ], where x is the latest version.

What you need to make a fully-functional autopilot with the 2.x code:

ArduPilot board [ http://www.sparkfun.com/commerce/product_info.php?products_id=8785 ]

Shield expansion kit with airspeed sensor [ http://store.diydrones.com/ProductDetails.asp?ProductCode=KT-0001-01 ]

GPS module (EM406 [ http://www.sparkfun.com/commerce/product_info.php?products_id=465 ] recommended)

XY and Z sensors [currently out of stock; we'll have them available by July]

FTDI cable [ http://store.diydrones.com/ProductDetails.asp?ProductCode=TTL%2D232R%2D3V3 ] for programming

[Optional] Two Xbee modules [ http://www.sparkfun.com/commerce/product_info.php?products_id=8742 ] for real-time wireless telemetry, with an adapter [ http://www.adafruit.com/index.php?main_page=product_info&cPath=29&products_id=126 ] in the air and a different one [ http://www.sparkfun.com/commerce/product_info.php?products_id=8687 ] on the ground/laptop side

ArduPilot 1.x is the navigation-only version of autopilot. It is a GPS-guided autopilot that controls the rudder to navigate to GPS waypoints, and the throttle to maintain altitude. It works with a stand-alone stabilization system to provide a full autopilot solution. The main code is the "Ardupilot1.x.zip" code (where x is the latest version) in the download section of the repository [ http://code.google.com/p/ardupilot/ ]. This code supports all GPS modules in NMEA mode.

What you need to make a navigation-only autopilot with the 1.x code:

ArduPilot board [ http://www.sparkfun.com/commerce/product_info.php?products_id=8785 ]

GPS module (EM406 [ http://www.sparkfun.com/commerce/product_info.php?products_id=465 ] recommended)

FTDI cable [ http://store.diydrones.com/ProductDetails.asp?ProductCode=TTL%2D232R%2D3V3 ] for programming

For aircraft use, a FMA Co-Pilot [ http://fmadirect.com/detail.htm?item=1489&section=20 ] for wing-leveling and stabilization

[Optional] Two Xbee modules [ http://www.sparkfun.com/commerce/product_info.php?products_id=8742 ] for real-time wireless telemetry, with an adapter [ http://www.adafruit.com/index.php?main_page=product_info&cPath=29&products_id=126 ] in the air and a different one [ http://www.sparkfun.com/commerce/product_info.php?products_id=8687 ] on the ground/laptop side

Instructions:

Complete manual [ http://docs.google.com/View?id=ddjmqgw3_43gm6gvggf ].

Open source essentials:

Latest autopilot code (for the board's main processor, an Atmega328) is here [ http://code.google.com/p/ardupilot/ ].
Latest multiplexer code (for the board's second processor, an Attiny, which runs the failsafe system) is here [ http://ardupilot.googlecode.com/files/Fail_Safe_v16.zip ]. Instructions for loading this code are here [ http://diydrones.com/profiles/blogs/how-to-program-the-attiny-on ].
If you want to build your own board from scratch, the necessary files and component lists are here [ http://diydrones.com/profiles/blogs/buy-bare-boards-and-components ].

Recommended UAV setup:

Airframe option one: Hobbico SuperStar [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGVZ3&P=7 ] (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 [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLWZ8&P=7 ], speed controller [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKSY5&P=0 ] and a LiPo battery [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWNZ0&P=0 ]. [If you don't already have one, you'll also need a balancing charger [ http://www.hobbycity.com/hobbycity/store/uh_viewitem.asp?idproduct=7028 ] and power supply [ http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6477 ].] 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 [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFRU7&P=ML ] (shown above). Performance can be improved with the modifications described in this post [ http://diydrones.com/profiles/blogs/705844:BlogPost:3387 ].

You'll also need:

A six or seven channel RC transmitter and receiver, with at least one proportional aux control, such as the Futaba 7C [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXTTM1&P=0 ] (digital, more expensive) or Tower 6XM [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLDP9**&P=0 ] (FM, cheaper). Both work fine.
Some servos [ http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDEL5&P=0 ] (at least three for ArduPilot 1.0; at least two for ArduPilot 2.x) and at least three female-to-female servo cables [ http://www.sparkfun.com/commerce/product_info.php?products_id=9187 ] to connect the RC receiver to ArduPilot.

Cool optional extras for your UAV:

A GPS logger [ http://www.amazon.com/i-Blue-747-Bluetooth-Receiver-Integration/dp/B000U7ZMTC/ref=pd_bbs_sr_3?ie=UTF8&s=electronics&qid=1230152410&sr=8-3 ] to record your mission and play it back in Google Earth
A tiny video camera [ http://www.hobby-lobby.com/video-camera.htm ] to record the flight
A wireless video setup [ http://www.rangevideo.com/index.php?main_page=product_info&cPath=8&products_id=98&zenid=244b0cd77d18aed28b6cb4a7860ae237 ] to see realtime video from the air

5:00pm