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  • David Melendez September 19, 2012 at 3:08am

    Software PWM is not doable with RPi and Linux directly, because Kernel scheduling. You will need a PIC/Arduino to do that job

  • Earl March 9, 2012 at 10:51pm

    Ok, what can we do with an APM2, RPi,Vision sensor,xbee coms,mission planner, and a high altitude balloon to put it on.,8 ch rc/tx and some servos and cameras.also a 2m/440mhx transciever and packet software.

    Earl

  • shane.sanford March 9, 2012 at 10:41pm

    There is a great deal of growing pains as small companies expand out into real production runs. Few accomplish it gracefully in the beginning (some never do).  Most organizations are able to hide the majority of the details behind the veil of secrecy that is pretty much been a necessity in the industry to survive.  Now we have “open” source / hardware projects taking the same steps (and stumbles).  However, these “open” projects have an expectation (and duty?) of being more transparent and thus every little mistake is under the magnifying glass.  The reality is in order to reliably acquire stock on key components relationships with distributers and manufactures have to be developed so when you need parts the scheduling of the silicon manufacturing actually happened 8-10 weeks ago.  Even small companies can make this happen but you need to know the right people to talk to get your name in the hat – usually you can do so with a very minimal upfront $$$.  Reality is chip manufactures have their machines scheduled 4-10 weeks in advance so their idea of quickly responding to unexpected demand is 6-8 weeks. 

    At $25-35 per board they are already using the Chinese supply lines to reduce cost to the extreme.  Now if supply doesn’t stabilize over the next 12-15 weeks then they are just idiots.

    With the APM2.0 I was in the queue for a long time myself and was impatiently counting down the days and often wished I had more updates (are we almost there Papa Smurf?).  DIY Drones is in an especially sticky position in that this is a very open project but at the same time they are looking at making a buck.  Personally I see nothing wrong with that, though there is a inherent conflict of interest between the two and it requires a great deal of effort to balance openness and the ability to make enough $$$ to keep things moving along.  Overall of a project of this size I give them a solid A- in balancing the two.

  • Earl March 9, 2012 at 9:32pm

    And how long did I wait for my APM2.0 I just got 3 days ago ???

    Earl

  • Jay Bryon March 7, 2012 at 2:16pm

    3.5 Watts is somewhat significant, but for larger platforms not so bad.  That said, it's not really optimized for the task, kind of a multitool when all you want is a flat head screwdriver, and a small one at that.  

    But I could see this for a SAR drone, using predator (object recognition/tracking software, not the drone) and an high res camera to search for people.  At that point it's less an autopilot and more a flying vision computer.  

  • Richard March 7, 2012 at 10:45am

    @Ellison Chan:

    The GPIO has both I2C and SPI interfaces on it, as well as a UART - all at 3v3, but not 5v tolerant like Arduino.
    There are only two hardware PWMs.

    - This info is all given in the Wiki - http://elinux.org/RPi_Hardware

    So, as shane said, this isn't a direct replacement for an Arduino.
    You'll use an Arduino for the basic stabilisation, then the RPi for advanced tasks, eg image processing.

    As for a camera - the RPi Foundation are planning to release a camera that plugs directly into the CSI port, and up until then a generic USB webcam could be used.

  • Andrew Radford March 7, 2012 at 5:08am

    @Scott - this would make a decent ground station side GCS, as long as a video in could be interfaced. It already has composite video out, and could just use Mavlink messages to drive the OSD like the Planner and Minim OSD do.

  • Scott Fraser March 7, 2012 at 1:14am

    um just out of interest how plausible is it to use this as a OSD in combonation with the ardupiolt?  

    the reason i ask this is because it is cheaper and more powerful than many on the market at the moment

    if people were interested an imu and gps could be incorporated though i now that would be a very long way of  

  • Chris Paulson March 6, 2012 at 7:37pm

    I think shane.sanford is dead on about how this fits into the existing AP system. The one thing that I'll add is that the interfacing legwork is done. You have Mavlink and ROS for any and all communications between a Raspberry PI type board and the APM. You can outsource some tasks, like telemetry, to the application processor and even free up the microprocessor to do a little bit more digital filtering or processing.

  • shane.sanford March 6, 2012 at 5:23pm

    Think of the Raspberry PI as a potential evolutionary step in the mid range processing power market just like the Arduino was in the low end microprocessor market.  It is bringing real processing power at a very low $$$ cost (along with relatively low weight, small size, and with a small power budget).  The Arduino will never have the processing power to do real image processing or other CPU intensive tasks. 

    If you are looking at the Raspberry PI as a straight replacement for what the Ardupilot is doing then you are missing the real advantages it brings to the table.  Sure you could interface it to something like ArduIMU and have a very nice auto pilot but the better use would be expanding the capabilities to image processing / swarm behavior / navigation through complex environments.

    Time will tell if the Raspberry catches on and succeeds or is just blah.  Given that they have already sold hundreds of thousands in preorders it looks like it may be interesting…

     

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