Raspberry Pi/ArduPilot Quadcopter

[RasLyme]

Hi so I am attempting to create a quadcopter with my Raspberry Pi paired with an ArduPilot to recieve the signals to be in real time. I have very little experience and will be updating this if anyone would like me to with my progress .

[RasLyme]

My first question is how to connect the two? I will be getting the ArduPilot in the next two weeks or so hopefully and I have seen that it would be good to hook them up directly via USB. May be a noob question, but what would I use to physically connect the two? Thanks!

[Funky Diver]

What are you trying to achieve?

Obviously the ArduPilot is capable of control.

[RasLyme]

Sorry if this is kind of vague, but I was going to use the Ardupilot as the real-time processor that would receive the RC signals through a receiver and connect to the Pi where that would do any other processes like navigation and things like that.

[Funky Diver]

Isn't that a bit counterproductive?

I was under the impression that ArduPilot was a drone solution so had autopilot built in including way pointing?

Or are you looking at replacing a standard PC with the R Pi to become the waypoint editor?

If that'd be the case, and I'm not poo pooing the idea, but I'd think your biggest challenge is going to be memory resource, in particular storing and loading map data. I was going to do something similar with RangeVideo gear using a net book with both greater processor power and memory and it struggled. That was running on Slitaz, and low resource linux distro.

[RasLyme]

Well I think it would be difficult to build to quadcopter wiht only a Raspberry Pi on it, seeing as it is not time-sensitive so I would need to use something like an Ardupilot right? I figure that I could run the time-sensitive stuff on the ardupilot then whatever else on the Raspberry Pi. I wasnt planning on controlling the drone with the Raspberry Pi, I'd do that with a laptop and a RC controller; but mount the Pi on the drone along with the Ardupilot. Sorry if im repetitive or not making much sense, I am very new to all this. If it helps, Im following guides such as this: http://ghowen.me/build-your-own-quadcopter-autopilot/

[Funky Diver]

Aaaah, so you're looking at replicating the features of ArduCopter?

If that's the case, then any arduino based flight controller would work well, and let the RPi do what you're wanting it to do. The up side of that is that's considerably less expensive to do than hunting down an ArduCopter.

[timbdesign]

Take a look at the series of articles by Andy Baker in MagPi magazine.
He's building a quad copter controlled by a Raspberry Pi.
http://magpi.techjeeper.com/The-MagPi-issue-20-en.pdf

[RasLyme]

Thanks for the magazine, ill use that as a reference also. Would you guys have any suggestions on how to connect the Pi and the Ardupilot? I'd imagine GPIO to GPIO but if so, which pins specifically? Thanks

[RasLyme]

Just got the Ardupilot 2.5.2 yesterday and is already all soldered up!

[Hove]

As you have the Ardupilot already, don't bother with the MagPi article - that's all about using a Raspberry Pi as the full flight controller - that is possible as the only part of a quad that needs real-time processing is the PWM signal driving the ESCs, and the Raspberry Pi provides hardware PWM - everything else can happen relatively slowly - say 50Hz and there's no need for accuracy in the rest of the code as the processing compensates for any errors in time. My code can easily achieve 200Hz but I limit it to 50Hz to leave space for new function in the future. It's only using interpreted Python.

Now you have the ArduPilot doing this anyway, what do you want the Raspberry Pi to do? Without knowing that, it's hard to say how to connect the RPi to the ArduPilot.

[RasLyme]

I guess the question I should be asking is whether it makes sense to have both the Pi and Ardupilot hooked up together or if its better to just have the Ardupilot in the first place. I got this idea of both of them rom an article someone wrote about building a quadcopter saying you could have the Ardupilot do the time-sensitive processes then have the Pi do the rest not-so-sensitive stuff, whatever that entails.

[Hove]

Can't help you on the ArduPilot side - I have not used one - perhaps try diydrones.com? I wrote the MagPi articles, and the Raspberry Pi is perfectly capable of driving a quad all by itself (+ ESC, motors, props, frame etc) - so it's really your call whether you want to play in the Arduino or Raspberry Pi world? You'll get better support in the Arduino world - there's only a few people here so far that have built a quad successfully enough to be helpful.

[morgul]

I think I can explain why you'd want more than an ArduPilot. As nifty as the ArduPilot is, you still need a base station for any heavily automated processes; for example, facial recognition or any machine learning projects.

Now, I'm not sure the Pi's a good fit for those either, but it gives you more options and breathing room. You could at the very least wire up a mic and make your drone operate on voice commands.

My naive solution would be to hook the radio to the Pi and then the Pi to the ArduPilot via serial (the 3DR radios are all just serial modems anyway), with the Pi forwarding the radio commands on to the ArduPilot, but also sending it's own MAVLink commands when required.

[shamakh96]

What if I want to use the SSH option , or VNC .. To control the raspberry pi remotely by Internet , and use the raspberry pi to Control APM from USB (of the Pi)

do you understand me ? , i mean i intend to a wider range of control , and get rid of (Radio low range)

[Metasyntactic]

There is actually pretty good documentation on how to do this.
http://dev.ardupilot.com/wiki/raspberry-pi-via-mavlink/
I would like to know how this is going?

I'm looking at doing something similar. I want the raspberry pi to receive GPS coordinates via GSM and pass them through MAVLINK to the ardupilot as well as using the pi to take near-infrared photos. When finished, I'll be able to monitor vegetation health of forests over the internet.