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DIY Project Solution: BBB vs RPi+Arduino

fustini

An acquaintance of mine organizing a STEM event asked me today:

"we're going to has some DIY astronomy stuff there. Would your BeagleBoard be a bit overpowered for that? I'm thinking there are going to be people there interested in making telescopes and needing to position them.  Perhaps that is more Arduino & Raspberry Pi [...]

Like I said, if you can point me to something (like Youtube video) as to why the Beagleboard is slicker, I'm more than happy to spread the word."

Here is my response:

 

Check out the video from this post: http://beagleboard.org/blog/2013-07-29-Five-years-of-DIY-hacks/


Five Years of BeagleBoard.org Video

http://www.youtube.com/watch?v=bIvkerJr5wE&feature=player_embedded


To clarify BeagleBoard vs. BeagleBone: BeagleBoard has additional features like DSP and is a more expensive board.  BeagleBone Black is $45 and fits in an Altoids tin (aka credit card sized).  It has higher processing power than the Pi (except for HD video due Pi's VideoCore GPU).  I also includes 2GB onboard Flash storage so no separate SD card is needed.  It is ready to boot up out of the box (no flashing SD cards, etc).


It would be great for any type of project that needs automation, motion control, remote sensing & web-accessibility (or all the above).  A telescope control system would be a great use case!  A BeagleBone Black is cheaper than Pi + Arduino.  Pi has limited hardware interfacing.  Networking with Arduinos is expensive and difficult.  BeagleBone Black handles all of that - and its completely Open Source Hardware.  This is great for engineering education and for design engineer & makers who need to optimize the Bone for their use case!

 

It has tons of I/O compared to Pi:

 

  • 7 Analog Pins [Pi has no analog input aka ADC]
  • 65 Digital Pins at 3.3V [Pi has only 26 pins total on its P1 header]
  • 2x I2C
  • 2x SPI
  • 2x CAN Bus [Pi has None; great for automotive projects, diagnostics, etc]
  • 4 Timers
  • 4x UART aka plain old serial [Pi has 1]
  • 8x PWM [Pi has 1 PWM and it is used for analog audio]
  • A/D Converter [Pi has none]


BeagleBone Black also has two 200MHz 32-bit microcontrollers built-in which can handle real-time tasks like generating signals, software emulation of protocols, reading sensors, controlling motors, etc.  In addition the BeagleBone Black has a more reliable power system and USB 2.0 system as compared to the Pi.

It has easy programming environments for hardware interfacing such as:
In short, I believe BeagleBone Black is a more cost effective solution than RPi + Arduino.

 

 

I'd appreciate the feedback from element14 Community members: Am I making a sound argument?  Are there additional points I should make?  Are there advantages of the Pi and Arduino that I am glossing over?

 

Thanks,

Drew

Parents

  • Hi Drew,

     

    Interesting topic! As I understand, most telescope positioning uses high-res optical encoders, so having a high-speed processor dedicated to counting pulses is really good I think, and use the other to control the motors.

     

    It is more convenient outdoors to run the BBB from a Li-Po cell since it has a built-in charger (I need to make this a blog post because it gets lost) than a RPI which needs a more inconvenient supply.

     

    LCDs are easily connected for selecting the desired object on either platform, but capes already exist for the BBB, or use a mobile/tablet for the UI. If not wifi, then possibly USB OTG cable from an android device, to the BBB - not sure if that is possible with an RPI.

     

    The tables for star positions, and the formulas for planetary motion are all open source since this information is as old as astronomy, and it is not difficult to compile for Linux. It would run faster on the BBB most likely.

     

    I'm not sure if many astronomers use CMOS now, maybe they do. However, there are some CCD cameras and decoders that connect via USB, and so possibly a good USB capability is needed for the high-speed data. At any rate, the ability to be able to select the sensor is important (whether that is CMOS or CCD), so a good USB capability is important. Or, for reduced cost but still high performance, a lower cost analog CCD cam could be interfaced.

  • in reply to shabaz

    shabaz wrote:

     

    It is more convenient outdoors to run the BBB from a Li-Po cell since it has a built-in charger (I need to make this a blog post because it gets lost) than a RPI which needs a more inconvenient supply.

    That's a very good point.  Battery backup would be an excellent feature for telescope electronics and also for a whole observatory, as power loss could ruin a time exposure or even a whole night's observing session.  The BBB's Li-Po ability provides an easy start in that direction.

     

    Yes please on the blog article. image

     

    If you have additional info on the BBB's charging characteristics or electronics, that would be very cool, but even if you just resubmitted your (already very informative!) discussion post, it would give this important topic greater visibility.

     

    Maybe we should suggest to Jason/Gerald that  providing a mounted Li-Po socket on the next colour of BB would be an attractive bullet point for embedded projects, and it would have minimal effect on BOM costs.  The mod is easy, but even simple soldering is a hurdle for huge numbers of people.

     

     

    Addendum:  I've been thinking about ways of routing the Li-Po path through a cape with the purpose of V and A monitoring by the BBB, not only of its own power but also of multiple external supplies and sinks.  Having its own backup power would make it a very effective power monitor and manager for a system, able to survive target voltages dropping all the way to zero even if it's normally powered by them.

  • in reply to morgaine

    I see that one UK supplier was doing the BBB for £23 so in fact even cheaper than the Pi in this case.

    More I look the more impressed with the BBB...I really like the run from LiPo Idea image

  • in reply to Problemchild

    Well that's done it ordered my first BBB from CPC ! image

  • in reply to Problemchild

    Is there much in the way of examples for the CAN bus ... My first project is for a Car would be nice to read the basic info direct from the vehicle .

  • in reply to Problemchild

    John Alexander wrote:

     

    Well that's done it ordered my first BBB from CPC ! image

     

    Oh dear, better fit a lock to your wallet quick.  You'll understand why once they start sending you their catalogues every few days.  It's a very dangerous site.  image

  • in reply to Problemchild

    Oh, I missed it! It's £30.99+vat now.

  • in reply to morgaine

    Done! Added a blog entry (as you guessed, I planned to have some more information, but it may be sufficient for now anyway).

    It's a good point that you mention, it would be worthwhile to alert them that a connector on their next board design would be great.

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