Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached
 
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Number Fifty
(@number-fifty)
Active Member
Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

Hi all, so I am by no means an IT expert, far from it. so this might be an easy fix but I am stumped.

I have set up a Raspberry Pi 3 b+ running Octoprint connected to the Prusa I3 Mk3S via USB, with a Logitiech Camera connected, and it was all working fine. I wanted to add some lighting, so I purchased this USB 5v LED lights ( https://www.amazon.co.uk/gp/product/B07SQVLRCD/ref=ox_sc_act_title_1?smid=A124YGLFVPBOL2&psc=1), however when I plug it in to the Rpi 3b+ USB, the Pi and the Mk3S suddenly lose connection and can not re-connect. and the Lights flicker, just slightly. Once I unplug the USB Lights, the Printer and Pi start talking like nothings happened. Has anyone got any idea what the heck is going on? 

 

On a second note, ones I can get the lights to behave themselves and do as they are told, is there anyway I can add a button to Octoprint to turn the lights on and off when I want?

 

Thanks all.

Publié : 03/10/2020 5:19 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

could it be that the lights over run the RASPI'S  or power supply's ability to power them?

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 03/10/2020 5:35 pm
Number Fifty
(@number-fifty)
Active Member
Topic starter answered:
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

@joantabb

That sounds like a sensible conclusion. Any chance you know where I can find out the 3b+ limitations in terms of USB power?

Assuming this can't be overcome with a larger power supply, but most likely a powered USB hub?

Thanks

Publié : 03/10/2020 5:54 pm
Number Fifty
(@number-fifty)
Active Member
Topic starter answered:
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

Do you think If I wired the lights to the required GPIO pins for their power, that it would over come this? or is the powered USB hub the only solution?

 

Publié : 03/10/2020 8:02 pm
Eewec
(@eewec)
Active Member
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

Powering the Raspberry Pi is something I just spent most of today researching. The 3b+ is powered with 5V 2.5A via the USB. It sounds like your lights are trying to pull more power. You need to put a relay and extra power line in the mix. This in one video that shows you how Lights and Pi Relays. For power, you can splice into the power output from the Pruse power supply with something like this. Just be careful to select the correct Amperage (One of these is how I plan to power my Raspberry Pi 4). DO NOT try to over volt/Amp the Pi - that's a good way to have a pile expensive rubbish.

Ce message a été modifié il y a 4 years 3 fois par Eewec
Publié : 03/10/2020 9:09 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

@numberfiftyltd

can you use a relay attached to the Pi, to switch the LED Load...?

Or a mosfet switch like they use for heatbeds?  

using a different power source for the LEDS.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 03/10/2020 9:29 pm
Number Fifty
(@number-fifty)
Active Member
Topic starter answered:
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

@joantabb

This was my fall back plan but I feel this may be out of my skill set, electronics and coding are black magic to me. Haha

Publié : 03/10/2020 9:31 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

get a usb wall wart, and a male to female USB cable, 
plug the wart in the wall, the cable in the wart and the lights in the cable!

Simples!

 

lol

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 03/10/2020 10:03 pm
Number Fifty
(@number-fifty)
Active Member
Topic starter answered:
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

@joantabb

The separate power supply is not what I meant, I was meaning using the Pi to switch the lights on and off. 

Publié : 03/10/2020 10:09 pm
bobstro
(@bobstro)
Illustrious Member
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

FYI: The Raspberry Pi 3 & 4B models are limited to a combined 1.2A @ 5V off the USB ports. Exceed that current draw and you are very likely to encounter unstable operation. The RPi pins are even more limited. Be very careful trying to drive much more than an LED off the GPIO pins directly or you might damage the board. A @joantabb notes, you want a separate power supply for the strip power. If you want to control the strip from GPIO pins, you'll want to use MOSFETS or something similar driven by GPIO pins.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Publié : 04/10/2020 6:07 am
Loak
 Loak
(@loak)
Estimable Member
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached

Hello all,

With a Pi 3 B+ doesn't the 1200 mA needs to be unlocked with max_usb_current=1 into the /boot/config.txt file ?

You will still have 500 mA by usb port, but you will have 1200 mA for all the ports.

MK3s Stock, PS2.3, Fusion360, Debian, Windows 10.

Publié : 04/10/2020 6:19 am
bobstro
(@bobstro)
Illustrious Member
RE: Mk3S, Pi3 b+ and Webcam all works great till USB lights are attached
Posted by: @loak

[...] With a Pi 3 B+ doesn't the 1200 mA needs to be unlocked with max_usb_current=1 into the /boot/config.txt file ?

That is the default now, no need to edit config.txt. I can't find the RPi official description right now, but a google search should locate the info.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Publié : 04/10/2020 2:59 pm
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