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Using Arduino => Motors, Mechanics, and Power => Topic started by: dliu001 on Aug 14, 2019, 12:57 am

Title: Servo shaking-PWM & PCA9685 Servo shield
Post by: dliu001 on Aug 14, 2019, 12:57 am
Hi There,

I am using PCA9685 to drive Servo, which just holds 1 drum stick(aroung 0.5kg). I used Adafruit library, which called Adafruit_PWM_Servo_Driver_Library, to have a test. It did work! However, when it reached the value of SERVOMIN(250) and SERVOMAX(500), the servo will be shaking.

1. I tried both 5V and 6V for power supply

2.The original value of SERVOMIN and SERVOMAX are 150 and 600.(These two value will not cause shaking problem)

3.The servo I used is Micro Servo - High Powered, High Torque Metal Gear.(https://www.adafruit.com/product/2307)

4.I set 'delay(500)' between the reach of SERVOMIN and SERVOMAX

The introduction in Adafruit website is really confused me. There are already the value of SERVOMIN and SERVOMAX. What is the 4096? Does anyone can explain to me? Thanks in advance.


Title: Re: Servo shaking-PWM & PCA9685 Servo shield
Post by: slipstick on Aug 14, 2019, 10:30 am
Please post the code you are using to cause this problem. Why do you want to change the values of SERVOMIN and SERVOMAX if you already have working values?

Steve
Title: Re: Servo shaking-PWM & PCA9685 Servo shield
Post by: Wawa on Aug 14, 2019, 11:18 am
Shaking could be the power supply related.
The 5volt supply should be able to deliver at least 1Amp per servo.

Do you wait until the servo has reached it's position before reversing.
What happens if you pause longer.

4096 is the number of steps of the 12-bit output of the PCA9685.
The code sets a number of them HIGH and a number of them LOW, to generate the servo signals.
Leo..