3D Robotics

Modular board strategy for ArduPilot Mega

In a previous post, I discussed our mainboard approach for ArduPilot Mega. In this post, I'd like to share our thinking about the expansion boards ("shields", in Arduino-speak). As you can see in the above diagram, the core ArduPilot Mega will consist of two layers, just like the current ArduPilot. The core autopilot board will remain constant, while the IMU board will come out in versions, improving as sensor technology evolves. But there is also the option to add a third layer, which is an expansion board for additional functionality. We will break out as many I/O (analog and digital) pins as possible to the expansion board, along with at least two serial ports. Some of the boards, such as the DIY sensor board, will be dual voltage. Some of the boards proposed above may be ones for which there would be enough demand that we'd make and sell them ourselves. Others may be created by the community. ArduPilot is an open standard, like the rest of Arduino, so we'd like to encourage people to come up with their own shields, just as the community has done with the core Arduino boards. So what do you think? Have we missed any obvious expansion board candidates? Any design decisions we should be making with the core ArduPilot Mega board or IMU to allow for more expansion options? (Remember, size is at a premium, so suggestions that require bigger or more expensive mainboards tend not to carry the day)
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  • 3D Robotics
    The USB is on the IMU to minimize the size of the mainboard (the IMU board has more room). It doesn't add much cost (~$3) to add that to alternate IMUs
  • Admin
    hi Chris,
    If I may, Shield for/ or plugging in RC RX directly to one of the boards might be good idea
    If shield are vertical plug in on the edge of mega offers more surface area for add-on in additional to box structure strength with simple spacers between shields on opposite edge ,
    Stacked boards also has some good physical attributes provided all the mount holes are aligned , the portion extending in the base board may hold servo plugs pins ,
    Pls ignore if these have been taken care or irrelevant, more to come :-)
    We know couple of things are effected or will effect others due to interference. Video TX , GPS, telemetry radio, gyro /IMU , so some thought has to be invested to counter interference in later stages.
    A suitable base airframe( probably high wing trainer) to be identified and detaching our self from electric propulsion only( gas/nitro) will open up lot of possibility IMHO. Adding a shield for using RPM sensor ( hall effect or other) , EHT probe.
    Precision low altitude sensor( ultrasound ) for future development for auto landing/take off is one area that is separates high end auto pilots from amateur stuff IMHO. this sensor is also useful for other options/possibilities like altitude calibration( reset runway altitude irrespective of MSL) , IFR operation etc
    Also telemetry shield which is not locked to Xbee opens other possibilities , Like mentioned before i bought a aerocomm product which had same capabilities of xtrend ( 1W, 112kbps , etc etc) but at almost 3rd of the price.
    suitable hobby quality enclosure for all this should not be far though not directly related to this thread now
    more to come
  • My only suggestion would be make sure you use stackable headers for the shields this time like the regular arduino shields. With the first expansion board that was made the headers were not stackable and were offset for additional boards.
  • Why is the USB connection going onto the IMU board? If it were on the main board then alternate IMUs wouldn't have to include support.
  • 3D Robotics
    Stik, ArduPilot has always had a dual power supply option (onboard regulator, in addition to using Rx power). We were planning to do the same with Mega. Is that what you had in mind?
  • I also recommend a separate power supply board for AP, payload, servos, etc...
  • What about if we put two slots on the ardupilot mega, one on top, one on the bottom which would double the amount of capacity for two shields. Another option is perhaps there could be an expansion shield which would have cables to come off it and allow additional shields to be plugged in and stashed elsewhere on the aircraft. The only limit that I see is the number of shields the ardupilot can take information from or maybe that isnt an issue
  • 3D Robotics
    Keep stacking! But based on community feedback, we may find that it makes sense to combine some functionality on a single board. Maybe we'll find a way to combine video/OSD with a telemetry data stream.

    Just one clarification. We already support a tracking antenna on the ground (it's part of ArduStation). This proposal is for a tracking antenna in the air, for directional transmission.
  • Wow those shield ideas sound awesome!

    But... what if somebody wanted to build a quadcopter with Live Video/OSD sent along with xBee telemetry to a tracked antenna on the ground?
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