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Can't Center Servos for Boe-bot — Parallax Forums

Can't Center Servos for Boe-bot

Pig_SooiePig_Sooie Posts: 1
edited 2012-12-04 14:42 in Robotics
We are trying to center the servos for the Boe-bot (Ch.2 Activity 4). For some reason, even though our circuit is exactly like the one in the diagram, the servo will not be centered. We can slow it down to a low speed but it will not stop even though we are sending exactly a 1.5ms pulse, with 20ms in between the pulses. Has anyone had a problem similar to this? We are using C instead of the PBASIC and an 8051 microprocessor rather than the one that comes with the kit. However, we used an oscilloscope to measure the pulse that we are sending from the 8051 and it is exactly 1.5ms with 20ms in between pulses. Thanks. for any help.

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-12-04 14:42
    Many continuous rotation servos (like the ones that come with the BOE-Bot) have an adjustment potentiometer. While sending the servo a 1.5ms pulse every 20ms, adjust this pot until the servo stops moving. (I thought this was part of the servo centering activity in the BOE-Bot book?)

    On the Parallax servos, the adjustment pot is inside the servo case and it can be accessed through a hole that's located just above where the wires connect with the servo case.

    On my BOE-Bot, the pot is blue with a white center. The white center can be turned with a Philip's screw driver.
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