Trouble getting the USB microscope working

#1

Hi,

Using linux (on raspberry pi, other arm based boards and x86), I’ve been testing this for a few days now.

It seems to detect ok:-

[dmesg output]
usb 4-1: new high-speed USB device number 2 using xhci-hcd
usb 4-1: New USB device found, idVendor=0ac8, idProduct=3420
usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 4-1: Product: Venus USB2.0 Camera
usb 4-1: Manufacturer: Vimicro Corp.
uvcvideo: Found UVC 1.00 device Venus USB2.0 Camera (0ac8:3420)

Then if i try an access it with just a command like: ~$ sudo v4l2-ctl --list-devices
It drops off, I need to physcially remove it and plug in again.

[dmesg output]
[43751.030029] usb 4-1: USB disconnect, device number 2
[43751.273946] usb 4-1: new full-speed USB device number 3 using xhci-hcd
[43751.385983] usb 4-1: device descriptor read/64, error -71
[43751.602090] usb 4-1: device descriptor read/64, error -71
[43751.818018] usb 4-1: new full-speed USB device number 4 using xhci-hcd
[43751.930104] usb 4-1: device descriptor read/64, error -71
[43752.146099] usb 4-1: device descriptor read/64, error -71
[43752.250206] usb usb4-port1: attempt power cycle
[43752.874046] usb 4-1: new full-speed USB device number 5 using xhci-hcd
[43752.875128] usb 4-1: Device not responding to setup address.
[43753.078168] usb 4-1: Device not responding to setup address.
[43753.282084] usb 4-1: device not accepting address 5, error -71
[43753.394085] usb 4-1: new full-speed USB device number 6 using xhci-hcd
[43753.395184] usb 4-1: Device not responding to setup address.
[43753.598207] usb 4-1: Device not responding to setup address.
[43753.802068] usb 4-1: device not accepting address 6, error -71
[43753.803087] usb usb4-port1: unable to enumerate USB device

I’ve tried the following kernels - same (or very similar) story with them all. Sometimes i get error -31 instead of -71.

4.4.154
4.19
4.9.59

I’ve tried it on x86 and arm arcitectures.

With and without powered usb hubs.

I’ve tried different drivers gspca_zc3xx vs uvcvideo . Both give /dev/video1 successfully. usb dropout is the same.

Just for completeness as most online guide say to use this, I tried guvcview , the result is the same in that it triggers the usb disconnection.

The VIMICRO chip used VC0345PLNAB seem to have good support within the linux kernel for quite some time with uvcvideo.

The issue feels like how the device is interacting with the usb bus …

I suspect it might be the usb cable, but i don’t have the 2mm JST connectors it looks to be using to make my own temp cable :frowning: … the DFrobot pack you sell with these will likely be in my next order :wink:

Just for reference here is the adafruit forum page serach for usb microscope.

https://forums.adafruit.com/search.php?keywords=USB+Microscope&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&sid=954bfa4efc589d5e3075d936f0867c83&submit=Search

The microscope itself:

Any help would be much appreciated.

#2

Have you tried ruling out a hardware failure by trying to plugging it into a Windows PC?

The next thing I’d look at is how you’re powering the Raspberry Pi…

I see on the Adafruit forum they had the following issue:

Also, just found the problem with the first 'scope. The internal PCB connector for the USB cable had two loose crimp contact pins (power, D+) that weren’t fully inserted. The most difficult part of the fix was figuring out how to open the case. The domed end cap can be released with a quarter-turn (no tools).

Cheers,

Marcus

#3

Hi Marcus,

Regarding powering the microscope, I’ve tried the following all with the same result.

  • Used two different powered usb hubs on the PI
  • Used a desktop PC’s usb port as well as the same two powered hubs (ubuntu)
  • Used different arm boards, a rock64 and a s905s (debian)

I’ll get hold of a windows laptop to test it, although it really doesn’t feel like a driver issue.

Yeah I saw that post on adafruit and I’ve had a look at the internal connector - 2mm JST by the looks - and the pins look to be contacting ok. I tested the usb cable as well with a multimeter and all wires test ok, so it doesn’t appear to be the cable itself. Pressing the the connector to the board a bit firmer did produce slightly different error messages.

What’s the warranty procedure if the windows laptop gives the same results?

Thanks,
Adrian