How to get continuous servo to go in opposite direction using PWM library?

Other Hardware Motors, Mechanics, Power and CNC
1

I am using 6 continuous servos connected to my Arduino Mega using Adafruit PCA9685 16-Channel Servo Driver. The servos go in one direction for a set amount of time and then stop, however I was wondering how I get them to go in the opposite direction to allow for my project to 'reset' once they have stopped. I've looked for hours online for help and no closer to an answer. I'm new to Arduino and the PWM library, so I'm just confused how to get it to go back the same amount it did in the previous time. My code to turn them is below:

 pwm.setPWM(0, 0, 1000);
    delay(2500);
    pwm.setPWM(0, 0, 0);

Any help would be appreciated, thank you.

2

You need to use values either side of the servo's mid-point, where it would be stationary.

3

Thanks so much for replying! I'm completely new to this all, how would I find the servo's 'mid point'? And would I need to change both parameters (for example setPWM(0, X, Y) so change both X and Y or just Y? For reference in using the 'Micro 360 Degree Continuous Rotation Servo FS90R' for all 6 servos. Thanks so much.

4

A servo typically has a control pulse in the range of, say 1000us to 2000us.
With a proper servo, the mid-point would be around 1500us.
For a continuous rotation ex-servo, this would be the point where the shaft was stationary.

5

So to find that would I just experiment by changing the .setPWM(0, X, Y) Y value until I find one for which it stops? Or do I want to use both the X and Y values?
And another question, when you say 1000us, is that what I'm using in setPWM(0, 0, 1000) or is that something different?
Thanks so much.

6

I don't have that library (no need for it) but your code is incomplete, so it's hard to advise you any further.

7

Sorry one final question, when you say no need for that library, does that mean I can use servo.write() type code even though I'm using a servo shield? Or do I have to use PWM with the shield?
Thanks so much for answering my questions.

8

No, I meant that I have no need for it, because I don't use/have that board.

Yes, if you've got enough spare pins (one per servo) you can control them directly from the Arduino, using the Servo library.

9

Okay I see. I might just use spare pins and code that way as PWM is confusing! Thanks so much for answering my questions, you've been so helpful.