Sharing grounds on a PCA9685

Using Arduino General Electronics
1

I am using these servo driver boards with an Arduino Uno to drive many LEDs. Can I just jump and share the grounds?

I accidentally hooked up the wrong grounds and noticed the LEDs still operated as normal. Wasn't sure if this was safe or I may damage something. I am not currently using any resistors as the board max amperage is not enough to damage them. I am only using the PWM and Ground pins.

If I can, this would clean up the project immensely by reducing the volume of wiring.

HiLetgo 2pcs PCA9685 16 Channel 12-Bit PWM Servo Motor Driver IIC Module for Arduino Robot https://www.amazon.com/dp/B07BRS249H/ref=cm_sw_r_cp_api_glt_fabc_6NA5N2NNZ11M7CMXV98X?_encoding=UTF8&psc=1

Thanks!

2

You have us puzzled. What do you see as "right" and "wrong" grounds?

3

Each LED has a PWM pin and the corresponding GND. I mistakenly swapped some of the ground jumpers on the wrong pins so that some LEDs where connected to the adjacent ground pin and not the corresponding ground pin.

I noticed that they still operated but was worried about letting the magic smoke out.

image
image988×941 106 KB

4

All ground pins are - or always should be - exactly the same electrical connection.

There are some reasons for connecting the ground in the right place, but not in this situation. The adjacent ground pins are essentially interchangeable. :+1:

1 Like
5

Hi,
Do you have a DMM?

Tom... :smiley: :+1: :coffee: :australia:

6

Yes I do. Are you hinting I should see if there is continuity across the GND pins?

7

Hi,

Yes , with the power OFF.

Would dispel your doubts.

You have a very powerful diagnostic tool there...

Tom.... :smiley: :+1: :coffee: :australia:

1 Like
8

I tested the continuity per your advise and proved that all the ground are linked together. I was happy to remove all that wiring.

Thanks!

9
10

This Topic has been locked as it is the identical or too similar your other post.
Please use the original post and do not duplicate.

1 Like
11

Could you also take a few moments to Learn How To Use The Forum.

Other general help and troubleshooting advice can be found here.

1 Like