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Activitybot 360 will only go backwards and spin in circles. Help! — Parallax Forums

Activitybot 360 will only go backwards and spin in circles. Help!

I purchased a ActivityBot 360 for my 9 year old son and I to learn how to code. We are using BlockyProp to write code. We used the provided code that is on the Parallax website and it just spins around backwards. I found a calibration code, but still spins in circles.



  • iseriesiseries Posts: 1,271

    Because one wheel is on the left and the other is on the right if both turn in the same direction, they will end up moving in circles.

    So, one wheel needs to have a positive speed while the other wheel needs a negative speed.


  • blittled2blittled2 Posts: 25
    edited 2022-01-11 21:26

    Look at how both wheels spin. You probably will see one spin clockwise and the other counterclockwise. I don't know Blockprop but if you give one wheel the negative value of the other wheel's number then rerun the code you should see both wheels spin the same direction as Mike mentioned. If the bot is going backwards then switch the values on both wheels .

  • ercoerco Posts: 20,182

    "Spins backwards"...? Are both motors turning or just one?

  • just one.

  • ercoerco Posts: 20,182

    Sounds like one servo motor isn't connected/programmed/working. Swap the servo connectors L/R on the Activity board and report back.

  • The left servo spins very fast, and the right servo only spins when you put your hand in front of the ping sensor, but very slow. Also both servos spin backwards.



  • ercoerco Posts: 20,182

    Any progress Jeremy? Did you try swapping servos? Lets sort this out.

  • we tried another project the found on the LEARN.PARALLAX.COM website. The IR Roaming code. the robot still wants to still go backwards. I did notice that one of the servos would rock-back-and-forth when you put you hand in front of the IR sensor, but the other would just spin out if control.


  • Okay, I ran the calibration code and it still goes backwards and just spins!

  • iseriesiseries Posts: 1,271

    The calibration code figures out what value of PWM to give to each motor so that when you drive it straight forward it goes straight.

    It will not fix the direction the motors go in.

    Maybe you need to take a picture of your setup to see what's going on. This is a very simple setup.


  • GenetixGenetix Posts: 1,669
    edited 2022-03-26 23:09


    Are you sure that you have the ActivityBot 360 and not the Original ActivityBot?

    The 360 has 4 wire servos (built-in encoder), while the original had 3 wire servos and used external encoders for positioning.

  • Also, have you made sure both servos are installed oriented in the same direction? If you're not sure, post a photo top-down.

  • yes, it the activity bot 350
    yes, the motors are both the proper direction
    I used the instructions on the website that has video and pictures.
    I feel that the board is bad.

  • I meant 360

  • GenetixGenetix Posts: 1,669


    Rarely are Parallax boards faulty.

    Have you tried new batteries?

    Double-check that all the wires and connectors are fully inserted.

    If that doesn't work then attach some pictures.

  • @Shelby1985 said:
    I meant 360

    Hi @Shelby1985

    Did you manage to solve your spin-in-circles issue ?

    If not, I wanted to offer you send an email to with a photo of your robot (top-down view) whilst it's connected to your computer via USB and powered on (power switch in position 2 with two green LEDs visible at the power switch). That way we could arrange a call to make sure this is resolved for you. Alternatively post the photo here if you prefer.

    We'd really like to be sure you are able to use your robot as intended!

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