PTZ camera motors are highly inaccurate

Raspberry Pi Cameras ptz-pan-tilt-zoom-camera-on-raspberry-pi
1
  1. Where did you get the camera module(s)?
  1. Model number of the product(s)?

Arducam 12MP 477P Pan Tilt Zoom(PTZ)

  1. What hardware/platform were you working on?
    Raspberry pi 4

  2. Instructions you have followed. (link/manual/etc.)

https://docs.arducam.com/Raspberry-Pi-Camera/Pan-Tilt-Zoom-Camera/quick-start/

  1. Problems you were having?
    PTZ focus motor is really inaccurate, for example using the tool provided in the instructions:

  2. When setting the focus distance, if I target 15,000 and then increase it step-by-step, there is a point (usually around 16,000) where the numerical value increases, but the actual focus position in the preview remains unchanged.

  3. Using the default step size, if I move the focus one step forward and then one step backward, the preview image may not return to its original position.

  4. The dmesg log from your hardware?
    //

  5. Troubleshooting attempts you’ve made?
    Verifying correct power and cable connection and that movement has no friction.

  6. What help do you need?

I’ve researched this issue online and found that stepper motor driver problems can be a potential cause. Could this behavior be normal for the product, or is it likely defective?

2

Haha we had that thing before. The focus motor in our unit also had a lot of slack.

What we did back then was
a) home the motor once after each power up ( i.e. dial the focus to its minimal value)
b) go to the focus value from below

More about b)
I do a focus scan from low to high, 3000 to 17000, and find the sharpest img was at focus 5500.
Instead of directly command the focus motor to 5500,
I first command it to 5300, then 5500

Depending on your use case, you might find those cheap security PTZ camera be of better value. Smaller, smooth pan tilt, autofocus, no naked wires, might even get waterproof.

Look for those that support the vendor neutral ONVIF interface. That allows you to DIY control it instead of through vendor locked apps

3

Thank you for the answer! I was honestly hoping it was something I did wrong and not an Arducam issue :sweat_smile: .

Regarding the cheap PTZ camera suggestion, it wouldn’t work for me because I need discreet photo quality. Do you know of any other embedded camera options similar to Arducam?