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Scribbler 2 hacker port; beginner — Parallax Forums

Scribbler 2 hacker port; beginner

myrkmyrk Posts: 3
edited 2012-01-28 17:17 in Robotics
Hello,

I'm somewhat new to Parallax products and circuitry in general, but I do have a bit of experience in low-level software. I recently bought the Scribbler 2 to try out the Propeller, and it works very well. Now I would like to extend it using the hacker ports, but I'm not exactly sure how. I have this small motor that I would like to connect for testing, and if I connect it to the high voltage ports and ground it works well but not with the Propeller ports 0 - 5 when I turn them to high. I'm pretty sure I'm doing something wrong, can anyone explain it to me?

Thanks.

Comments

  • ercoerco Posts: 20,256
    edited 2012-01-28 12:35
    You can't control a motor directly from the ports. At a minimum, you'll need a transistor switch or relay. More likely a motor controller or H bridge for full control. You could also use a continuous rotation servo.
  • ratronicratronic Posts: 1,451
    edited 2012-01-28 12:40
    myrk the hacker port in the S2 uses a voltage translator between the port and the Prop. Usually voltage translators have weak outputs and would require some kind of interface to power a motor. Also note that the translators also require a certain amount of drive to over come their outputs to drive the inputs to the Prop.

    Edit: Welcome to the Parallax forums!
  • myrkmyrk Posts: 3
    edited 2012-01-28 13:19
    Ok, thanks.

    So two more questions:

    Would the power form the propeller port be good enough if it didn't have a translator?

    And what is the voltage from the hacker port?
  • ratronicratronic Posts: 1,451
    edited 2012-01-28 13:22
    myrk a motor requires to much current to be driven directly from a Propeller port or a translator you would need to use something like as erco suggested.

    Edit: the hacker port is 5 volts.
  • myrkmyrk Posts: 3
    edited 2012-01-28 13:32
    I see. Thanks.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-01-28 14:17
    myrk,

    Do you have any LEDs? You could use LEDs with 330 Ohm resistors to test the hacker port's signal lines.

    In my opinion, the S2 would be a much better robot if Parallax hadn't used the level translators. The translators interfere with the Propeller receiving some signals (such as the pulse from the Ping sensor).

    The hacker port has three rows of pins. The bottom row (toward the back of the robot) are the signal pins. The middle row is 5V for driving small loads such as a servo. The top row is ground.

    You should be able to access the power from the batteries directly by connecting a jumper near the serial port. I believe the jumper allows access to the battery power from the serial port. You could use this power source for driving larger loads.
  • TtailspinTtailspin Posts: 1,326
    edited 2012-01-28 17:17
    And don't forget this place >>>> http://www.parallax.com/go/s2 :thumb::thumb:


    -Tommy
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