Category Archives: Uncategorized

USB camera management on Linux

So you have a USB Camera plugged in to your Ubuntu box.  You then notice that your camera’s led is on (could also be true for an integrated web camera on a lap top).  This could  be because you left a camera app running and forgot to turn it off (exit). The app Cheese for example or worse yet you closed all camera apps but you have been hacked.  I won’t go into how to clean your PC here but if you want to disable your USB/integrated camera here are two very useful lines”

  1. exit cheese or your camera app
  2. sudo modprobe -r uvcvideo <– to disable the camera
  3. restart cheese no LED or camera image
  4. exit cheese
  5. sudo modprobe uvcvideo <—- to enable the camera
  6. restart cheese LED and image

Now this will not be preserved across reboot so the following might prove equally useful:

sudo vi /etc/modprobe.d/blacklist.conf
add the following two lines at the end of the file
#Disable webcam
blacklist uvcvideo
toggle “cheese” to see if you can view webcam contents or reboot

remove those two lines to restore webcam usage.

Webserver rebuild after failed uprade

I updated my webserver with Ubuntu 18.  Then I decided to upgrade to Ubuntu 19.  But first I needed a backup of WordPress.  I decided on “UpdraftPlus“.  I backed up my WordPress data and moved it to a thumb drive.  Then for the move to Ubuntu 19.  It failed.  After about 1.5 hours the process just hung.  I did a hard reset and that was it.  I should also point out that I had no power to the PC internals – MB, disks so I am assuming that shortly after I started the upgrade the Power supply failed.  Can’t complain:  10 years x 24 hours a day.  Took me 4 days to rebuild the box.  I had good Readme.files but many of the commands in them were no longer valid because mysql, apache2 had changed their syntax for their commands/statements.  Lots of Googling.  Anyway once I got the box configured  to support WordPress and got WP downloaded and installed I once again downloaded the UpdraftPlus plugin for backups/restore.  I moved the backup files from the thumb drive to “wp-content/updraft” on the newly build PC and using UpdraftPlus restored the data.  PERFECT!!!  About 2 minutes and my WordPress blog was recovered vs. 4 days of rebuilding a PC.  UpdraftPlus is definitely a winner.

PTZ not working in Blue Iris 5 with Yoosee camera

I recently received a new PTZ  camera (works with the Yoosee video application)  I ordered the camera from AliExpress. I got the video side working fairly easily with the Blue Iris camera app, but had some real difficulty getting the camera to pan/tilt/zoom. In an associated page I will show you what I did. It is quite easy actually.  You can read the details  here .

bought a new “cruncher”: AMD RYZEN 1700 and AMD RADEON RX 580

Yesterday I bought a new “cruncher”:  a Dell AMD Ryzen 7 1700 with an AMD Radeon RX 580.  As soon as I got home I removed Windows 10 and installed Ubuntu 16 (tried 17 on this node but had issues).  This PC required the installation of new AMD GPU PRO driver support because Einstein@Home did not recognize the onboard GPU.  There were errors in the AMD procedure which I will address later in a more detailed page on this website.  Now for the “bad news”  Once the drivers were successfully installed Einstein@Home is reporting the GPU as being a 480 and not a 580.  I will have to look into this and depending on what I find contact the store to see what is going on.