What are the advantages and disadvantages or each?


The PX4 looks like the very old days when APM had many boards and no case. Just looking at the advertisement I have no idea why I would want to trade in my APM 2.5+ for a PX4?




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Agreed - maybe in a year's time there are compelling features on the horizon. At the moment, I'm delighted by the APM  as is. If it ain't broke..

I'm not sure what J means that the APM is neither mature nor easy to get started with. It's been around for 3 years+, 4 generations of hardware and peripherals that's been tried and tested by thousands. Arduplane is very easy to get started with if you use the manual (also matured). The PX4 based Arduplane does not even have a version 1 yet. We all know there's a long road between a new platform and a stable platform.

So for me, I'm buying another APM.

git clone https://github.com/PX4/Firmware.git

There is something in there on running  completely different operating systems on the same chip, one on each core.

Would be great if 3drobotics was putting their professional coders on exploring stuff like that instead of re-inventing the wheel as a heckaflexihexigon.

16 times faster 32 bit with FPU compare to 8 bit :-)


APM 2.5+ processor - Atmel ATmega2560

  • 8-bit, 16MHz, 16 MIPS, AVR RISC-based microcontroller
  • 256KB ISP flash memory, 8KB SRAM, 4KB EEPROM


PX4 Processor - ARM Cortex-M4F

  • 32-bit, 168MHz, 252 MIPS RISC ARM CortexM4F microcontroller with DSP and floating-point hardware acceleration (FPU).
  • 1024KB of flash memory, 192KB of RAM.
  • MEMS accelerometer and gyro, magnetometer and barometric pressure sensor.
  • Flexible expansion bus and onboard power options, SIMD extensions.

The PX4’s much more advanced processor is 16 times faster than the APM 2.5+, but the software is somewhat experimental.

I can use Eclipse to compile the PX4 firmware.

If the ArduPilot would use the new Arduino Due (ARM CortexM3, 32-bit, 84 MHz, 100 MIPS, 512 KB Flash, 96 KBs of SRAM, 16 KB ROM) I would choose that.

I am leaning toward the PX4.

And no one here as talked about taking the whole "Drone" thing to the next level.  

Flying between way points is great but what if there is a tree or building in your way? What if you want to obay voice commands? How about a Microsoft kinetics to since and map the surroundings.  This is not new.  With Vision you could recognize object ... 

A number of groups/people like myself are working on integrating the opensource ROS (robotics operating system) into PX4. 

Could you elaborate on what is better about PX4's "Software"?

As far as I understand ardupilot will be the software run (or vbrain)?

"The PX4 software is a product of 5 years of development & is light years ahead of the APM which is neither very mature nor easy to get started with according to many posts on this forum."


All indications are that 3DRobotics will build on the good shit in order to stay in the game. There is a fork out there with the name of Ardupilot, but with the contents of the the PX4. It looks like the PX4 guys and 3DR are working together but have decided to keep their code separate for whatever reason.  In essence it comes across as 3DR adding some development support to the PX4 team at the moment. If you buy the VRbrain or the 3DR board & put the PX4 software on it (either branch), you'll have a system that is competitive with OP, Autoquad, & Paparazzi. This could be wrong in the details--if anyone wants to jump in who knows the actual intentions, feel free to correct me.

Mark. I am interested in your ROS.
You see the big picture since you approach the task with a professional entrepreneurial mind compare to a hobbyist.
As a professional Microsoft software developer (also good with hardware) I'd like to help you with the ROS development. Also develop for iOS and Android using Xamarin (MS C# + Xamarin dev tools).
There are many commercial applications for inexpensive, reliable drones communicating to a mash network (XBee).
More over email :-)

This is an open source, open hardware project.  Why not design your own case and publish the design file?  You can get plastic 3D printed pretty cheap these days from companies like Shapeways or many others.

The problem with the APM is that they use a weak old processor instead of a cheaper and much faster modern one in order to make the programming easier.  Then they even used old analog methods like PPM for stuff it's not intended for like inter-processor communication so that they could borrow code from Paparazzi.

To their credit, they made it work.  But what you have is a slow, old processor using old and inefficient analog techniques to do it's job.  Pile that on top of using a programmer's "training wheels" system like Arduino and you have the APM.

I like my APM, and it works alright, but it is certainly a legacy device and not a modern design.  It's certainly not the future of autopilots. They took the easy path to getting an autopilot on the market and now the growing pains will certainly be the death of the APM as we know it today.  You can only take old processors and analog thinking so far, and waiting for Atmel to catch up to the rest of the processor market has already left them in the dust.

The PX4 is a bunch of upstarts that rather rudely forked from the OpenPilot project, so I have no special love for them, but I imagine they have their reasons and if OP can't kick down the hardware then I suppose there's not much else you can do.

This is my personal view and nothing official. APM has had a very good relationship with Arduino, and much of the early success came from that union. But even at a very early stage Arduino code was stripped out and replaced with faster equivalents to make our application possible. Today there's pretty much nothing left of Arduino, beside pin layout and using the .pde files to make compilation with the Arduino IDE possible.

But still there was a valid reasons for sticking with Arduino. So 3DR and APM devs waited a long time for Arduino to come out with a ARM based solution, so that we could continue that relationship. But sadly even to this date, the Arduino Due isn't really all there and the choice of ARM (Atmel SAM3X) is far from optimal for our needs. So when the PX4 was announced, we jumped. I do not know details about the next 3DR APM3, but I would not be surprised if it is an evolution of the PX4 hardware.

@Jake, good luck with trying to remove PWM and PPM support. That would cause a shit storm like no other, stripping away support for 99% of the receivers in use today. And PPM is actually extremely resource efficient as a one way communication between two chips. Requires much less resources then decoding a serial bit stream.

APM3 as an evolution of the PX4 sounds perfect. I will not get and new hardware until I see what APM3 has to offer. I hope that they release details soon!





PX4 is a fork of OpenPilot?  Source?  First I've heard of that!

Sure, Arduino environment is somewhat limiting.  But I sure need those training wheels!  It's an interesting question where we would be now, if we had started on a different path, not using Arduino.  Would we be further ahead, because of the extra power and flexibility of a more modern system?  Or would we be further behind because there would be less developers?

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