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New Chinese C Hardware Robot — Parallax Forums

New Chinese C Hardware Robot

ercoerco Posts: 20,255
in Robotics
:)    http://www.ebay.com/itm/Microcontroller-Entry-Level-Study-Small-Line-Tracking-Smart-Car-Robot-DIY-Kit/281607491013


Little line tracker bot; Title says microcontroller, description says: It is a small DIY line tracking robot car that the C program has been recorded, after assembled, it can work.
But one photo shows the schematic, all hardware comparators. How DO they do it? :)

Comments

  • Duane DegnDuane Degn Posts: 10,588
    How does one program a comparator in C?
    The motors can only move forward using a transistor.
    I personally think it's still pretty cool. Even without a microcontroller it's still pretty educational. Though I don't think people should buy from such a dishonest seller (they might not be dishonest, they could just be ignorant).
  • Heater.Heater. Posts: 21,230
    I did not know comparator chips were so intelligent now a days.
    I'm also fascinated by the idea of getting complex behaviours out of circuits with no programmable devices.
    Back in the 1970's or so Wireless World published an article on a robot snail that demonstrated memory "Cybernetic Cynthia". She of course used a capacitor for her memory. The state of charge of that cap was changed by  external inputs and she adapted here behaviour accordingly, with a memory effect.  
    Wireless World also had a line following bot in 1972 that would roam the floor, avoid obstacles, and then search for the line when it's battery  was running down. Following the line it would end up at some power terminals at which it would rest  until recharged. Then it would resume exploring the room. All done with 6 transistors ! http://cyberneticzoo.com/cyberneticanimals/1972-free-roving-machine-m-f-huber-british/


  • TorTor Posts: 2,010
    Some years ago I read about a guy who builds tiny robots (real ones, not remotely controlled) out of a few transistors. He had a whole swarm of them crawling around his apartment, collecting dust. Saved work. But he had to herd all of them away if he wanted his mother to visit, she had a thing with bug-sized things scurrying around.
    No link, IIRC I read about it in a physical magazine. May have been New Scientist so it's possibly searchable.
  • Sam_sneakSam_sneak Posts: 14
    How does one program a comparator in C?

    One can't, but this speaks volumes about Chinese vendors hooking into search engines with product that isn't what it seems.
  • ercoerco Posts: 20,255
    Maybe it's a C++OOParator.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2015-08-06 21:39
    I don't know about C, but programming a comparator in Spin is a piece of cake. Here's a snippet:
    PUB LM393

dira[PIN1]~~
dira[PIN7]~~
repeat
outa[PIN1] := get_adc(PIN3) > get_adc(PIN2)
outa[PIN7] := get_adc(PIN5) > get_adc(PIN6)

    I sure the compiled code will fit in the LM393's very limited EEPROM. :)

    -Phil
  • ercoerco Posts: 20,255
    The real genius of PhiPi is that he comes along and playfully injects a valuable nugget of info like that in an otherwise inane conversation.


    Bravo, Sir, Good on ya! 
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2015-07-12 23:36
    One thing I forgot, though. Most pre-programmed LM393s from DigiKey are open-collector. Here's the factory default program:
    PUB LM393
  outa[PIN1]~
  outa[PIN7]~
  repeat
    dira[PIN1] := get_adc(PIN3) < get_adc(PIN2)
    dira[PIN7] := get_adc(PIN5) < get_adc(PIN6)

    -Phil
  • Martin_HMartin_H Posts: 4,051
    I doubt it's an attempt at fraud. It seems more like fractured English due to the person not understanding what they're saying. 
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