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Hellweaver666
(@hellweaver666)
Active Member
USB-C port no power?

Hey folks, I’m looking to add some simple 5v led lights to my printer setup. On my Prusa mini+ I was able to just connect an esp8266 running WLED to the built-in usb port and it just worked but I don’t seem to be able to do the same thing on my Mk4 using the usb-c port. When I do I get no power to the esp8266 

I realise I *could* solder some wires to the 5v on the back of the display but that seems far too much like hard work (and riskier!). Does anyone know what is going on?

thanks!

Posted : 27/03/2024 6:19 pm
Eef
 Eef
(@eef)
Estimable Member
RE: USB-C port no power?

Did your Prusa Mini have an USB-C? Maybe/probably not. 
USB-C is a two way connection. So there must be an agree on which side is the host and which side is the guest. 
In the guest side, the power lines are pulled down to mass with two resistors. 
If there are no pull down resistors the power lines are not activated. 
See https://hackaday.com/2023/01/04/all-about-usb-c-resistors-and-emarkers/ for nice explanation. 

We will do what we have always done. We will find hope in the impossible.

Posted : 27/03/2024 9:09 pm
JP Guitars
(@jp-guitars)
Estimable Member
RE: USB-C port no power?

You could just take a feed off the 24v power supply then use a boost buck converter to drop it down to 5v. A boost bucker is only a few quid/bucks/euros.

Posted : 27/03/2024 9:16 pm
Hellweaver666
(@hellweaver666)
Active Member
Topic starter answered:
RE: USB-C port no power?

In retrospect, I realised I wasn't using the micro-usb port on the Mini, I was actually using the full-sized usb (and the micro-usb was running octoprint).

Now that I'm using Prusa Connect I have a usb-drive always plugged into the usb port so that's no longer an option. There is a 5v and ground pad on the back of the display so I'm tempted to just hook into that since it's closer to my LED strip. But then it might just be easier to plug a couple of wall-warts and run a cable from there.

Posted : 27/03/2024 9:32 pm
bowtie6
(@bowtie6)
Active Member
RE: USB-C port no power?

I realize this is more than what you asked for...  But have you looked at the model for the MK4 light bar setup in Printables?  I installed this and it works very well.  I ended up using a very inexpensive 24v power supply I bought form Amazon.  I've read about issues with taking power from the MK4's power supply, so this separate power supply works perfect...

This is the LED light bar setup

Second LED strip on the back...

And this is the 24v power supply (the one with the blue dot).  They are cheap.

Posted : 28/03/2024 3:28 pm
Hellweaver666
(@hellweaver666)
Active Member
Topic starter answered:
RE: USB-C port no power?

It’s super cool and I have something similar on my Mini but my Mk4 is in the enclosure so I’ve rigged up a light bar that works nicely with that. Just gotta figure out the power situation (also I like to use WLED with 5v LEDs because then I can make it change colour to indicate the status like the XLCD via HomeAssistant 

Posted : 28/03/2024 3:46 pm
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