donjones
Posts: 2
Joined: Thu Oct 18, 2018 1:41 am

RP0W: USB camera works while measuring current , doesn't when fully soldered to micro connector.

Thu Oct 18, 2018 2:16 am

Hi community,

I have a bit of a weird problem. I have a USB webcam from a laptop I want to use with a RP0W.

Here are my tested scenarios: [works, yes|no]
[yes] Cam soldered to USB Type A connector and RP3B
[yes] Cam soldered to Type A with positive lead detached and bridged with multimeter to measure current and RP3B
[no_] Cam soldered to Type A plugged into OTG adapter to B Micro and RP0W
[no_] Cam soldered to USB Type B Micro connector and RP0W
[yes] Cam soldered to Type B Micro with positive lead detached and bridged with multimeter to measure current and RP0W

I measure the same current (and 5V) with both connector/board combinations, lsusb lists the camera and I get the blue LED lighting up on the camera when starting up motion on Raspian.

Only with the Micro connector completely soldered and connected to the RP0W it's not listed with lsusb or works ...

I am out of ideas.

Maybe I can solder the camera to GPIO and not use the port altogether?

Thanks in advance, cheers!

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Imperf3kt
Posts: 1380
Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: RP0W: USB camera works while measuring current , doesn't when fully soldered to micro connector.

Thu Oct 18, 2018 4:30 am

The Pi0 and Pi0W lack a USB hub, so my guess is without the OTG cable, the Pi isn't detecting whether the camera is a host device or client device.

I suggest bridging a 100 Ohm resistor between pins 4 and 5 on the micro USB port.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

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thagrol
Posts: 876
Joined: Fri Jan 13, 2012 4:41 pm
Location: Darkest Somerset, UK
Contact: Website

Re: RP0W: USB camera works while measuring current , doesn't when fully soldered to micro connector.

Thu Oct 18, 2018 1:06 pm

Imperf3kt wrote:
Thu Oct 18, 2018 4:30 am
The Pi0 and Pi0W lack a USB hub, so my guess is without the OTG cable, the Pi isn't detecting whether the camera is a host device or client device.

I suggest bridging a 100 Ohm resistor between pins 4 and 5 on the micro USB port.
Or force the zero into host mode via config.txt by adding:

Code: Select all

dtoverlay=dwc2,dr_mode=host
Note to self: don't feed the trolls
If you believe "L'enfer, c'est les autres" (Hell is other people) have you considered that it may be of your own making?

donjones
Posts: 2
Joined: Thu Oct 18, 2018 1:41 am

Re: RP0W: USB camera works while measuring current , doesn't when fully soldered to micro connector.

Sun Oct 21, 2018 8:09 pm

thagrol wrote:
Thu Oct 18, 2018 1:06 pm
Imperf3kt wrote:
Thu Oct 18, 2018 4:30 am
The Pi0 and Pi0W lack a USB hub, so my guess is without the OTG cable, the Pi isn't detecting whether the camera is a host device or client device.

I suggest bridging a 100 Ohm resistor between pins 4 and 5 on the micro USB port.
Or force the zero into host mode via config.txt by adding:

Code: Select all

dtoverlay=dwc2,dr_mode=host
Sadly, changing the config.txt doesn't make a difference in behavior. Neither one of the three dr_mode options worked.

I can see how increasing the resistance might trigger something though. After all, when I used the multimeter it must've increased the resistance somewhat right?

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