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The new PX4 Pixhawk module is an evolvement of the existing FMU and IO modules and completely compatible. The main difference is the target audience: While the FMU and IO stack is super small (the size of an average 8 ch RC receiver) but in some ways almost too densely packed, Pixhawk has more space, more serial ports and more PWM outputs.

As the above picture shows, there are two groups of servo connectors, one main group of 8 outputs which are wired through the backup processor, and an auxiliary group of 6 outputs directly wired to the main processor. The port labeled "RC" can take normal PPM sum or Futaba S.Bus inputs, the port labeled "SB" can read RSSI our output S.Bus to servos. A Spektrum satellite compatible port is on top (labeled SPKT/DSM).

The basic operation is the same, and the software is shared. Inside Pixhawk a FMUv2 and an IOv2 do their duties on a single board (and developers will find that the software will refer to FMUv2 and IOv2)

The main differences between old and new are:

  • 14 PWM outputs vs. 12 PWM (old)
  • All PWM outputs on servo connectors (old: 8 on servo, 4 on DF13)
  • 5 serial ports vs. 4 (with some double functionality, so only 3 in some configurations on old version)
  • 256 KB RAM and 2 MB flash vs 192 KB RAM and 1 MB flash (old)
  • Modernized sensor suite (latest generation)
  • High-power buzzer driver (old: VBAT driven, not as loud)
  • High-power multicolor led (old: only external BlinkM support)
  • Support for panel-mounted USB extension (old: not present)
  • Revised, improved power architecture
  • Better protection on all input / output pins against shorts and over voltage
  • Better sensing of power rails (internal and external, e.g. servo voltage)
  • Support for Spektrum Satellite pairing (needed some manual wiring work in v1, but also software-supported)
  • No more solid state relays on v2 (was not really used)
  • Connectors easier to disconnect in case, as the surrounding plastic helps to place the fingers correctly (more on this in a separate post)
  • Case prevents one-off failure operation of servo connectors
  • The new unit is consirably larger, has the same height, but offers in general more handling convenience.
  • External power supply similar to existing 3DR power brick (every unit comes with a free module)

Both generations offer the same backup / override processor that allows failover to manual if the autopilot fails in fixed wing setups. For software developers the differences are nicely abstracted in the PX4 middleware, and can be sensed / configured at runtime.

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  • HI Steve,

             maybe what you are looking for is in this manual(the light patterns) the wiki has exact sound samples to play as mp3 files to here what the various alert tones are...here

    http://3drobotics.com/learn/#Pixhawk_Autopilot

          hope this helps

         HZL

    ps firmware loads are a PITA no matter what platform.. practice makes perfect...or at least more tolerant of the PITA process...

    • Thanks. I am aware of these. In spite of what was asserted, the complete light sequencing meaning and final patterns were not there for planes at the time I asked. Tridge acknowledged this in the "old" forum. The tones were there long ago. What I believe is still missing (but can be figured out) is the meaning of the small LED lights. I know the blinking blue has confounded more than a few. There is also the slowing dimming red power light.

      The FW downloads have gotten much easier as either MP or Plane FW evolves. If you note my original post I was dismayed that the hype said easy and seamless transition to Pixhawk.. For the early adopters, I don't believe it was. The arrogance of some at 3DR did not sit well with me and others. I am happy now and would like to let this RIP. 

      Oh, I would like to see the promised accessories for the Pixhawk. The Digital Airspeed sensor recently appeared but the Aux Light and USB port are MIA.

      Thanks again,

      Steven

  • Sorry for butting in , but "Maybe the Pixhawk is not the FC for you?" is a lame attempt to make the questioner feel stupid, and not a member of the "Club". Well if there is a club, you (not you personally) threw it open to everyone by selling Pixhawk to the general public.The request for a complete list of LED meanings is not unreasonable, you guys wrote the code for ***** sake, I have done a fair bit of software development in my time, and a lot of it was not in your handheld high level languages like C but in assembly language, One thing i learned, is that when you grant the plebs permission to use your software, assume that they don't know all the arcane ins and outs like you do, but they also don't know the easy stuff , like what the bleeps and flashes mean unless you tell them! Complete documentation is as important as the software itself.

  • Where can you buy it? 3DR robotics doesnt have it and same for all stores listed here. Where is the best place to preorder it? Preferably I would like to buy in Europe and not have to get it from the USA.

  • Moderator

    Who are the Developers associated with the Pixhawk? Who is doing the testing?

  • How does this compare to the APM?  What mission planning software is used? How many waypoints?

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