Introducing ArduPilot: the world's cheapest autopilot!

The decision to port the Basic Stamp autopilot to Arduino turned out to be an unexpected opportunity to make something really cool. I've taken Jordi's open source RC multiplexer/failsafe board, and mashed it up with an Arduino clone to create "ArduPilot", perhaps the cheapest autopilot in the world. ($110! That's one-third the price of Paparazzi)

Here's what it is:

A custom PCB with an embedded processor (ATMega168) combined with circuitry to switch between RC control and autopilot control (that's the multiplexer/failsafe, otherwise known as a "MUX"). This controls navigation (following GPS waypoints) and altitude by controlling the rudder and throttle. These components are all open source. This autopilot is fully programmable and can have any number of GPS waypoints (including altitude) and trigger camera or other sensors

As with the Basic Stamp autopilot, to make a fully autonomous aircraft you need to combine this navigation autopillot with a stabilization system, for which we turn to our old friend, the FMA Co-Pilot (off-the-shelf infrared sensors and control board to keep the plane flying level), which controls the ailerons and elevator.

By using Jordi's MUX, which allows us to switch from autopilot to manual RC control in hardware, we gain several advantages over the Basic Stamp:

1) Because the switching isn't handled by the processors, we don’t need to drive servos in real time, which means we don't need stand-alone servo driver chips (thus a simpler board)

2) We also don't need “mirroring” subroutines to pass through servo commands in RC mode (simpler code)

3) Don’t need power regulator, since we’re using regulated output from the RC receiver (simpler board)

4) The built-in MUX failsafe is cheaper and simpler than using a stand-alone one.

I've taken a quick pass at the schematic and PCB (Eagle 5.0 format) for ArduPilot, although this will evolve as we go through the hardware testing cycle: Schematic, PCB board. You can buy the board here. Arduino code coming soon in alpha now.

All together, this can be the basis of a sub-$500 UAV:


--ArduPilot PCB: $10

--Boarduino kit + FTDI cable: $35 (subtract $17.50 if you already have a FTDI cable)

--PicoSwitch: $20 (we'll probably build this in the board in the next rev)[UPDATE: Jordi's now incorporated that into the board above. It's a TinyAVR chip ("IC3", $2.75) and its associated programming interface jumpers ("ISP")]

--EM-406 GPS module: $60

--Multiplexer chip : $1

--8 Samtec TSW-108-25-G-T-RA right angle servo connectors (available as a free sample): $0

(That's a $110 autopilot, thanks to the open source hardware. By comparison, the Basic Stamp version of this, with processor, development board and failsafe board, would run you $300, and it's not as powerful)


--FMA Co-Pilot: $70

Plane and RC equipment:

--Hobbico SuperStar (includes motor, battery and ESC): $109

--6-Channel radio system (with proportional control for channel 6, to calibrate FMA system): $109

--Three servos: $45

TOTAL: $440

Views: 52903

Comment by Adam French on May 11, 2008 at 6:17pm

This looks great, and nice idea bringing the mux onto the board. Looking forward to seeing the code development.

Comment by Scott James on May 11, 2008 at 7:11pm
Great work Chris!!
Comment by Borgel on May 11, 2008 at 9:16pm
Very nice board!

Out of curiosity, is there any particular reason you chose that GPS module?

3D Robotics
Comment by Chris Anderson on May 11, 2008 at 9:29pm

Only that it's a good and cheap SIRF III chip set that's worked very well for us in the past. Of course any GPS module would do....
Comment by Borgel on May 12, 2008 at 2:13pm
Ah, ok. I'm just collecting knowledge.
The SIRFIII seems to be the chipset of choice (and Sparkfun the supplier).
Comment by Wayne Dancer on May 13, 2008 at 9:58am
Excellent work Chris! I love to see an elegant solution to something complex.

Comment by Brian on May 14, 2008 at 10:09pm
This is the type of project I've been looking forward to finding... I'm not an electronics guy, but I am learning the basics so that I can follow a set of plans and have a basic understanding and be able to assemble projects. I'm somewhat new to this awsome site and have a newb question... Are details going to be posted so that those of us in less of the know can take on something like this as an opportunity to learn? Frankly, without details and mentorship from a guru I'll never get beyond flying a camera around with an auto-pilot keeping it stable...

3D Robotics
Comment by Chris Anderson on May 14, 2008 at 10:23pm

No fear: we'll post full details and Arduino code in the next few weeks. Eventually we'll even sell the boards pre-made, components and all, although that's not really the spirit of the site and not a business we want to be in ourselves. But there are many like you, who'd rather not solder components on boards if they don't have to.

Comment by Brian on May 14, 2008 at 10:55pm
Thanks Chris,
I'm fortuante enough to work with an electronics guy who's doing the teaching. Personally I learn best by doing so I'd like to take on a project, even if I ended up using something else (like the stuff your working on now, which is GREAT NEWS). I was looking at the projects posted on the main page, would you suggest just going for a project like the Geocrawler 3 w/the basic stamp? Is the postings detailed enough for a true beginner to fumple through?

Any kind of timeline for the premade boards? I'd be willing to beta

3D Robotics
Comment by Chris Anderson on May 15, 2008 at 3:19am
Yes, the Basic Stamp instructions are detailed enough for a beginner, and if you don't mind spending the money on that you'll be well prepared for the more capable ArduPilot when it's ready. We may have beta pre-made ArduBoards by July, but stay tuned for updates.



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