http://www.perlmonks.org?node_id=1195697


in reply to Perl, JavaScript and Strandbeests

Wow, Excellent post. Your RaspberryPi cluster does interest me. I would use it for robot control. One Pi per limb, a few for sensor input, etc.
I'm not really a human, but I play one on earth. ..... an animated JAPH

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Re^2: Perl, JavaScript and Strandbeests
by marto (Cardinal) on Jul 21, 2017 at 12:06 UTC

    One pi per limb sounds like such overkill.

[reply]

      I agree with zentera that it looks like a really neat project, I agree with you that using one Pi per limb is a bit overkill. Depending on how many GPIO are required per limb (or let's say each joint in each limb), GPIO expanders or shift registers would fit the bill.

      I like the SN74HC595(N) series chips. Eight extra input/output pins for three GPIO, and you can daisy chain them (I've done a maximum of four for 32 extra pins using only three GPIO)

      I would suspect you'd also want some form of analog in/out as well for precise feedback. MCP3008's provide eight analog inputs, and something like the MCP4922 provide your analog outs (you could also use a digital potentiometer, or an Arduino via I2C/SPI/Serial). Even with all of that connected, on a Pi3, there will still be GPIO and cycles to spare.

[reply]

        "Even with all of that connected, on a Pi3, there will still be GPIO and cycles to spare.

        My thoguhts exactly.

[reply]
      One pi per limb sounds like such overkill.

      Didn't Bill Gates say who needed more than 64k of ram? :-)

      Imagine a complex robot, with rotating wrists, totally manipulated 3 joint fingers and thumbs, with real lifelike motions as protrayed by this Strandbeest's thread. Furthermore it must be reporting position back to the brain cpu, and function autonomously in case of brain overload.

      In otherwords it needs to be agile for sex-bot work. :-)

      I'm not really a human, but I play one on earth. ..... an animated JAPH
[reply]

        "Didn't Bill Gates say who needed more than 64k of ram? :-)"

        It was 640K (see Conventional_memory), and apparently, no he didn't.

        As for the rest, that a useage case I'd never considered. Without additional hardware a single pi could control upto 28 servos usning software and the onboard GPIOs.

[reply]

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