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QTI HomoBot connection? — Parallax Forums

QTI HomoBot connection?

IzzyIzzy Posts: 24
edited 2009-02-07 03:28 in Robotics
Hello!
I need assistence because I bought a QTI Line Sensors Kit and and I have a Homework Board, but looking the manuals it put that I must connect one of the QTI Sensor to the pin of one servo and I don't know how to connect them =S
Please, can someone help mee?

Thanks in advnce!
Izzy.

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Sorry for my english, I'm spanish.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-02-06 17:18
    The QTI sensor does not connect to a servo. You may be confusing "servo connector" with "servo". The QTI sensor requires +5V (Vdd) and ground (Vss) and provides a signal. +5V is a red wire. Ground is a black wire, and the signal is a white wire.

    Some of the Stamp boards have "servo connectors" which are just headers (pins) with +5V, ground, and a Stamp I/O pin made for plugging in a servo or a sensor that requires the same 3 connections. The Homework Board does not have this and you have to make the connections by yourself to the sockets on the Homework Board. Some people use a 3 pin long header with the same length pins on both sides, plug this into the little breadboard area, and make connections to it using jumper wires. This allows you to conveniently plug in a servo or sensor like the QTI instead of directly using wires.

    You can just use jumper wires to connect the red wire of the QTI sensor to Vdd, the black wire to Vss, and the white wire to any convenient Stamp I/O pin.
  • UghaUgha Posts: 543
    edited 2009-02-06 17:19
    A better name for a homework board bot might be hobobot [noparse]:)[/noparse]
  • IzzyIzzy Posts: 24
    edited 2009-02-06 17:32
    Sorry Ugha ;P

    Well Mike, I mean that one of the pin long header is connected in the hole of the servos. I attach a photo modified.
    If you look it one of the 3 pin head is in the place of one of the 3 servomotor pin head.

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    Sorry for my english, I'm spanish.
    QTIoccuping.JPG
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  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 17:59
    Hello Izzy,

    First of all, I recommend the circuit and code in Faster QTI Subroutine Source Code (.zip). This download is available from the QTI Line Follower product page.

    Next, just move the whole circuit down a bit to make room for your servo headers. I will attach a picture in the next 10 minutes or so. If the picture doesn't show, try coming back in a little while and reload this page.

    <edit> Picture attached, see below. </edit>

    Andy

    attachment.php?attachmentid=58500

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    Andy Lindsay

    Education Department
    Parallax, Inc.

    Post Edited (Andy Lindsay (Parallax)) : 2/6/2009 6:57:51 PM GMT
    modified circuit.jpg
    271 x 327 - 70K
  • IzzyIzzy Posts: 24
    edited 2009-02-06 18:09
    Thanks Andy, I tried to do it for my own and one of the servomotors started to throw smoke.
    when you upload the picture i will connect again

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    Sorry for my english, I'm spanish.
  • PropabilityPropability Posts: 142
    edited 2009-02-06 18:40
    ·Mike said:

    The QTI sensor does not connect to a servo. You may be confusing "servo connector" with "servo". The QTI sensor requires +5V (Vdd) and ground (Vss) and provides a signal. +5V is a red wire. Ground is a black wire, and the signal is a white wire.



    I wish it was that way but the power pin is actually the white and the red is the signal. What I did was take the 3 pin cable and reversed the red and white at one end and marked it to show it was. That way I was able to use it in the servo header on the BOE. Here is a picture.
    pal1.jpg
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  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 18:53
    Sorry for the delay Izzy. The modified wiring diagram has been added to my post (three posts up from here).

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • IzzyIzzy Posts: 24
    edited 2009-02-06 18:58
    @ Andy, and I don't need Resistors?

    Thanks people, in special Andy.

    Izzy.

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    Sorry for my english, I'm spanish.
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 19:19
    Izzy,

    That's correct, no need for resistors.

    The code and circuit from Faster QTI Subroutine Source Code (.zip) does not require resistors.

    Andy

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 19:23
    Also,

    A Faster QTI Subroutine (.pdf)·accompanies Faster QTI Subroutine Source Code (.zip).· They are both on·the QTI Line Follower product page.· Make sure to follow the instructions carefully.· Test the QTIs first without the servos.· Then, test your servos using code from Robotics with the Boe-Bot to make sure your servos still work after releasing smoke.· If they do still work, try the code that monitors the QTIs and controls the servos.

    Andy

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • IzzyIzzy Posts: 24
    edited 2009-02-06 19:53
    Hi again Andy, I connected the servors and the left servo it's okey, but the right when I put the battteries it started to throw smoke again and smells =S
    I will try the code for servos, but trying the LineFollowWithCheckQtis.bs2 doesn't works

    Izzy.

    EDIT: CONFIRMED, MY RIGHT SERVOMOTOR IS DEAD.

    ANOTER QUESTION:
    THe Home Boe-Bot Kit uses: Parallax (Futaba) Continuous Rotation Servo no?

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    Sorry for my english, I'm spanish.

    Post Edited (Izzy) : 2/6/2009 8:05:27 PM GMT
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 20:14
    I'm sorry about your dead servo.

    Yes, it's the Parallax Continuous Rotation servo, which is a Futaba standard servo, modified for continuous rotation.

    Make sure to try CheckQtiSubroutine.bs2 and use electrical tape on paper to verify that the QTIs are sensing the line.

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • IzzyIzzy Posts: 24
    edited 2009-02-06 20:40
    yes yes, they "reconginize" the line, but when I upload the LineFollowWithCheckQtis.bs2, the servomotors don't do nothing.
    I don't know why xD (i'm very unlucky ='[noparse][[/noparse] )

    And one more thing, in the QTI program with 4 sensors the center sensor detect the line, and with 4 sensors the 2 center sensors detects the line or what?

    Thanks in advance.
    Izzy

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    Sorry for my english, I'm spanish.
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 22:23
    The program makes the servos stay still until you put on top of the line. At that point, your Boe-Bot will try to turn in place because one of the servos is not working. When it loses the line, it will stop moving, so it would just make a vary brief motion.

    Yes, both of the middle QTI sensors should detect the line. If you take a look at LineFollowWithCheckQtis.bs2, the code for %0110 is full speed forward, but the code for %0100 and %0010 makes the HWB-Bot (HomeWork Board Bot) turn slightly.

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • IzzyIzzy Posts: 24
    edited 2009-02-06 22:36
    So when I had replaced the broken servomotor, the program will runs? Because, when I tryed anything happens (well the servomotor started to throw smoke and smells)

    Thanks in advnce,

    Izzy.

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    Sorry for my english, I'm spanish.
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2009-02-06 22:48
    Yes, it should work. Make sure to carefully follow all the instructions in the PDF. Pay special attention to the test code to make sure all the QTIs can detect the line.

    Andy

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    Andy Lindsay

    Education Department
    Parallax, Inc.
  • EzsynnEzsynn Posts: 119
    edited 2009-02-07 03:26
    Ugha said...
    A better name for a homework board bot might be hobobot [noparse]:)[/noparse]
    That's My Idea!

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    BWIN ON DA POWAH WIFIN U!!!
  • UghaUgha Posts: 543
    edited 2009-02-07 03:28
    I know... it's a good one, that's why I suggested it!
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