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:

Autopilot:

--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)

Stabilization:

--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: 48868

Comment by Tom P on May 15, 2008 at 10:57am
Why not a dsPic? If you start from my code the board will be 50% smaller :-)

3D Robotics
Comment by Chris Anderson on May 15, 2008 at 8:54pm
Tom,

First, great to see you here! I'm a fan.

Second, we went with Arduino because of the really strong open source support it has, from the excellent IDE to the community and libraries that are growing around it. This is simply a case of picking a platform that will make our job easier going forward as people share code and hardware that we can use.

As for the size, we can easily make the board 50% smaller ourselves by moving to SMT versions of the components, but frankly the board is quite small as it is and on our fixed wing autopilot we don't seem space or weight constrained at this point. (For the blimp, however, we are moving to a SMT board)
Comment by Carl Henrikson on May 18, 2008 at 2:32pm
Great stuff. Maybe in the future the Ardupilot could be made as a daughterboard to the ArduinoNano ? The Nano seems almost ideal for UAV use, it's only 18mm x 43mm 0.73” x 1.70”. Unfortunately, they are not shipping yet, but they're taking orders for shipping in mid-june. http://store.gravitech.us/arduino-nano1.html
I don't know the weight of the board, but I'll let you guys know when mine arrives.
Of course I'd like to beta!

3D Robotics
Comment by Chris Anderson on May 18, 2008 at 3:55pm
Carl,

Actually, we can make ours (or at least the Arduino components) even smaller than the Nano since we don't need all those breadboard pins on the bottom and the built in power regulator (we use the regulated power from the RC receiver). Basically, switching to surface-mount components would allow us to make the entire autopilot the size of a RC receiver. But given how small ArduPilot is already, is there really much to be gained? It would be a tiny plane indeed that couldn't fit it as is.

-c

3D Robotics
Comment by Chris Anderson on May 18, 2008 at 8:02pm
Actually, Carl, I've looked more closely at that Nano and it really is a nice board. The big selling point for me is the 4-layer board with a ground plane thoughout, which will do a nice job of electrical noise reduction. Perhaps we should offer one version of ArduPilot as a "shield" that just plugs into the Nano, for those who either have a Nano already or want a generic Arduino as well as an autopilot.

-c
Comment by Michael Evans on May 18, 2008 at 9:03pm
wow great work looking forward to seeing it in action! will it have a go-back-home failsafe also? this would be great for people who do long range FPV stuff

3D Robotics
Comment by Chris Anderson on May 18, 2008 at 9:15pm
Michael,

That's easily programmed. The entire thing, code and hardware, is open source, so people are free to add any and all functionality and features they want.

We should have boards with code ready by mid July.

-c
Comment by Wyliest on May 28, 2008 at 12:00am
What is the weight of this set up, not counting the plane and RC equipment? Just the autopilot and the stabilization

Moderator
Comment by Brian on May 28, 2008 at 8:46pm
Chris, the boards that will be done in july, they are fully assembled w/all the good stuff?
Can we pre-order? I'd like to get one that's assembled but also want to take a stab at building one myself (more for learning). The link you posted for buying a board has the ArdupliotBeta3 design, is that something you'd recommend or is the final release coming soon?

I'd also like to thank you and others for the willingness to help out new folks. I've gleaned a lot from our brief interactions and the postings of others on the site and believe I'm ready to get going. While I see a lot of potential in the basic stamp project, for now it comes down to $$ and this looks like the best bang for the buck.

Moderator
Comment by Brian on May 28, 2008 at 9:22pm
Does this system support Spektrum D6? Also wondering the same about the FMA Co-Pilot.

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