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Need some help with a PCA9685 to pilot a LED ribbon

Posted: 12 Sep 2019, 05:37
by rudloffl
Hello all,

I need some help to get my project to work. I want to control a LED ribbon (12v) from a wemos D1 (with the latest Mega) via a PCA9685. It's highly inspired from that https://mellbell.cc/blogs/projects/rgb- ... using-pico.

I cant find the solution to control the transistors from the PCA9685. When i connect directly the 3.3v to the transistor base, it works fine, but I can not get the PWM to work. I worked a little bit with modes (16 and 14) with no success.

Has anyone achived a similar project ? What's the detail I'm missing ? Are the transistors OK ? Should I find a different GPIO extender?

Any help is appreciated.
Capture d’écran du 2019-09-11 22-26-44.png
Capture d’écran du 2019-09-11 22-26-44.png (53.91 KiB) Viewed 2166 times

Re: Need some help with a PCA9685 to pilot a LED ribbon

Posted: 13 Sep 2019, 06:03
by rudloffl
I will try to control LEDs without the PCA9685. Let me know if I should use a different piece of hardware.

Re: Need some help with a PCA9685 to pilot a LED ribbon

Posted: 15 Sep 2019, 04:59
by rudloffl
I used the espesy GPIO directly to control the transistor and it works perfectly fine.

However, I would like to understand why I can't get the PCA9685 to work.
Do I need to had a small transistor between the one controling the 12v Leds and the PCA ?
Any idea what I should do to get it to work ?

Re: Need some help with a PCA9685 to pilot a LED ribbon

Posted: 23 Sep 2019, 19:12
by rudloffl
Victory !!!

I got it to work, I "just" had to change teh mode2 to "0x14"