ESP32 + FCOB LED 24V how to ground with USB-C?

Issues
1

Hello guys,

I hope you can help me with my problem - I already tried a lot of things.
Problem is the LEDs are randomly flashing and blinking (as always with ground problems).

My Setup is: Diagram of the setup
ESP32 powered by USB-C
Voltage Level Shifter 3,3V to 5V
FCOB LED 24V, 5 Meter, 720 LED/M powered by 24V Powersupply

And I know the most common issue with this after solving the voltage difference is the ground.
It may sound stupid but I managed to get the same ground for the LEDs and 24V Powersupply but how do I get the ground of the USB-C Cable to have the ground for the ESP32?

Thanks for the help.

2

It’s there already, where you connected the PSU to the ESP’s GND.

Your problem is the level shifter wired wrong, LV goes to 3.3V supply, HV to 5V supply, your input goes to LVx, and the signal to the strip on the corresponding HVy.

1 Like
3

Thank you very much, you solved my problem and saved my evening!

4

From your diagram, it looks like you’re using an I2C levelshifter.
It’s very likely, that will contribute to your issues.
Checkout the appropriate items in the KB: Levelshifters. Even if you manage to make that one work now, it will cause you grief in the future.

I would recommend a 74AHCTxxx based shifter, much simpler to wire, only needs a single 5V supply.
Don’t forget the 100nF decoupling capacitor.

Other than that, your layout is reasonably good.
I’d be careful about using the JST connector on the strip for more than data.
They’re not rated for much more than a few amps of current.
Likewise the barrel connector to the PS, over 3A they have a disturbing tendency to melt…
Pay attention to the size of wire for your power connections and use hardwired or screw terminals where you can.
Data connections use smaller wire (24-22AWG) and should include both a separate data and ground line.

5

Thanks for that detailed answer.
I’ll order the level shifter you recommended, sine as you said I got it to work but it’s flashing bright withe every 30-40 seconds.
And going to get better cables for power.

Thank you very much for the great tips, I’ll come back with the result next week.

6

If you have resistors around you can replace the one on the high side for the line you’re using with 1K instead of the 10K that’s there by default and it’ll then be way better.

7

Hey guys,
since I’m fairly new to the electronics world, I’d like to ask some questions in advance for next week.

  • Why does the current I2C level shifter work even without a 5V power supply? And what difference does the power supply make?
  • How can I make the complete wiring simpler and more robust? Preferably with a PCB board?
  • Can I operate the ESP32 and the level shifter on the same 5V power supply?
  • How does the ESP32 manage to connect to the Wi-Fi so quickly after being turned off?

Pictures of the wiring.

Thanks for your great support so far :slight_smile:

Edit: I have no resistors around, I’ll buy a set of them.

8 
Why does the current I2C level shifter work even without a 5V power supply?
And what difference does the power supply make?

Can I operate the ESP32 and the level shifter on the same 5V power supply?

The I2C shifter is not recommended for reliable operation.
What you have may work, but it does so poorly and will cause you grief (either now or in the future or both).

Look up the recommended Levelshifters as mentioned earlier. As a matter of fact - reread this thread, there’s good advice in the 4th message (still)

For further info on your setup, start a new topic.

9

Yes, you can take the 5V ftom the ESP board.
Why it works now I don’t know since the 5V is required to set the level to which to convert to.