[RESOLVED] ServoBlaster - Continuous servo bug (auto rotate)

[valx76]

Hi, I'm facing to a rotation bug in ServoBlaster..

I'm using these values:

Code: Select all

1500us : Idle
1530us : Pulse left
1480us : Pulse right

For example :

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echo 1=1500us > /dev/servoblaster

BUT, my problem is the (continuous) servo which rotates itself sometimes.. I mean, I make it to rotate to the right, I stop (idle), rotate to the left, stop (wait some seconds), and sometimes it will begin to rotate again itself and don't stop until I give it pulse left or pulse right value (it will not stop anymore with idle pulse)..

Do you have an idea ?

EDIT: I'm using an external battery for the motor (5V 2.1A). The battery GND pin is not connected to the RPi GND pin (otherwise, the motor is crazy sometimes).

[joan]

What connections do you have between the Pi, the servo, and the servo power supply?

[mikronauts]

Is your servo calibrated?

Most continuous rotation se3rvos have a hole leading to a potentiometer that you use to calibrate the stopped (1500us) position.

Some cheap servos have pots that drift over time.

[valx76]

Wow, fast answers, thanks !

My servo is DF05SR.

@mikronauts: I have a hole in the servo which should be a potentiometer yes, but I don't know how to calibrate it..
And please note that the servo can work normally 2min without any problem, and starting to bug after that amount of time so I'm not sure if it's a calibrating problem..

@joan: I've uploaded an image for the connections.
NOTE: The GPIO-4 connected servo is non continuous (and is working fine).

[mikronauts]

You calibrate the servo by sending it continous 1500us pulses, then

turn the pot right, then left, to find the range the servo does not move in

then set the pot for the centre of the "dead/no movement" space

[valx76]

Right, I'll try it, but I really don't think that this is the problem..
I'll let you know !

EDIT: mikronauts -> That solved the problem, that was the calibrate which was buggy.. Thanks a lot !