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by Joel_Mckay
Sat Oct 13, 2018 6:02 am
Forum: Automation, sensing and robotics
Topic: OpenCV and Computer Vision Help
Replies: 2
Views: 1367

Re: OpenCV and Computer Vision Help

The Pi camera modules are quite good, and do have a v4l2 driver available that makes it easy to open in the OpenCV api. For robotics, the mjpeg codec will be the cleanest option, but keep an eye on the resolution versus frame-rate relationship of the hardware. Utilities to calibrate camera settings:...
by Joel_Mckay
Thu Oct 11, 2018 12:16 pm
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

We'd just use fbgrab or scrot, and send that over for checking. We also have ways of capturing data through the DSI slot rather than HDMI, if necessary. None of it is terribly difficult, but somebody needs to set aside a chunk of time to actually do the work and then maintain it. I assumed verifica...
by Joel_Mckay
Thu Oct 11, 2018 11:44 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

I made a start on a system that used pi zero in gadget mode to act as a USB stick with a test image on it. GPIO was connected to the RUN pins. I had it booting the latest image and switching over to composite mode to test network functionality as well, but had to switch to working on something else...
by Joel_Mckay
Thu Oct 11, 2018 10:26 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

Good luck with trying to implement a test framework that tests everything for a linux machine that does....everything. No offense was intended, and hopefully my input was not considered derogatory :-) (my communication skills often don't articulate my intentions very well...) I am surprised an orga...
by Joel_Mckay
Thu Oct 11, 2018 1:48 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

There was a very recent fix for a CMA (IIRC) fragmentation issue that eventually caused things, I think in Kodi, but probably elsewhere as well, to grind to a halt. Could this be related? I believe it was an upstream kernel change that exposed the issue of small memory allocations bunging things up...
by Joel_Mckay
Wed Oct 10, 2018 1:15 pm
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

Interesting. Initially when I saw this thread I kicked off a playlist on youtube which went on for hours (occasionally switching between full screen and not). Memory kept creeping up, so I thought there might be a leak, but eventually it stabilised and when the tab was closed, went back to normal. ...
by Joel_Mckay
Wed Oct 10, 2018 3:59 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

Joel's earlier reply may help if you want to try it: #To enable the chromium GPU acceleration: # 1. people generally enable the OpenGL module # 2. and remove "--disable-gpu-compositing'' from /etc/chromium-browser/customizations/00-rpi-var # Incidentally, I left chromium out of our release given it...
by Joel_Mckay
Wed Oct 10, 2018 1:52 am
Forum: General discussion
Topic: Power supply RasPi 3 B+ and Adafruit Stepper Motor HAT
Replies: 3
Views: 1342

Re: Power supply RasPi 3 B+ and Adafruit Stepper Motor HAT

@MBlec Our club may have 2 or 3 extra CNC Motherboards available at the end of the month: http://www.micrometer.xyz/cdn/node/67 Also, note the power supplies we recommend, as eight NEMA17 * 2 phase bipolar stepper motors at 2A per field can easily exceed a 32A 12v peak load. However, we are giving a...
by Joel_Mckay
Mon Oct 08, 2018 12:27 pm
Forum: Troubleshooting
Topic: Problem getting Verizon USB730L modem to enumerate.
Replies: 2
Views: 1014

Re: Problem getting Verizon USB730L modem to enumerate.

Vendor specific help should be included in their support pages, but this device is likely supported in a new kernel: http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=2749 Also, the "modem manager" in gnome/MATE tends to probe for these devices automatically these days. Run this command b...
by Joel_Mckay
Mon Oct 08, 2018 6:27 am
Forum: Advanced users
Topic: cross compile QT "statically"
Replies: 8
Views: 1088

Re: cross compile QT "statically"

Statically built small utilities are common, but Qt is huge with many dependencies. There are distro which focus on minimizing installation size: https://www.yoctoproject.org/ Often it is possible to unpack a static '*.a' lib and link it as regular '*.o' files, but it creates a difficult to maintain...
by Joel_Mckay
Mon Oct 08, 2018 5:04 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

This doesn't do anything :?: cups.service couldn't even be found (maybe, because I dont't have printer set up?). That is correct, and the configuration options that tell processes like apt to automatically download and cache package lists can be a pain-in-the-network depending on your timezone and ...
by Joel_Mckay
Mon Oct 08, 2018 3:19 am
Forum: Advanced users
Topic: cross compile QT "statically"
Replies: 8
Views: 1088

Re: croos compile QT "staticlly"

If your system has a normal writable root mounted, than try: sudo apt-get update sudo apt-get install your-package Sometimes a usb wifi adapters can allow access to boards where an Ethernet jack is missing (or boot up on a pi with a network jack). While I have statically linked things like wxwidgets...
by Joel_Mckay
Sun Oct 07, 2018 10:38 pm
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 1163

Re: raspberry pi b+ old preloaded sd card

It's a diagnostic which is useful for users of mainline OSs. If your speciality OS leaves out such diagnostics, that is all the more reason NOT to recommend it to beginners with startup problems. Please stop recommending it except to your intended user base. I'm afraid at present you are spreading ...
by Joel_Mckay
Sun Oct 07, 2018 9:45 pm
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 1163

Re: raspberry pi b+ old preloaded sd card

Probably not the case here. The lightning bolt appears along with the four long four short flash pattern when trying to load pre-Pi3B+ OSs on a Pi3B+. It occurs because of the hardware/firmware mismatch rather than low PSU voltage. The blink codes are helpful... but I generally leave those icon ove...
by Joel_Mckay
Sun Oct 07, 2018 11:16 am
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

I have a 125 MBit Internet connection. I don't think, it's my network. YouTube only need a maximum of 150 KB to play a video at 720p. I don't know about background updates. How can I find that out? sudo cat /etc/systemd/journald.conf sudo systemctl status packagekit sudo systemctl status cups.servi...
by Joel_Mckay
Sun Oct 07, 2018 10:13 am
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 1163

Re: raspberry pi b+ old preloaded sd card

@mattmiller Perhaps the read-only root overlayfs may take a bit to understand, but there are menu icons they can click to switch modes (documented in a readme.txt). Yet the latter b.) is practically identical to the former a.) with about 80 problems solved people will eventually encounter, applicati...
by Joel_Mckay
Sun Oct 07, 2018 8:04 am
Forum: Troubleshooting
Topic: No HDMI Output Although TV is recognized by RPi 3 B+
Replies: 22
Views: 5014

Re: No HDMI Output Although TV is recognized by RPi 3 B+

That output sounds a lot cleaner (especially if under load), and I'm glad to hear you are back up and running.
=)

Cheers,
~J~
by Joel_Mckay
Sun Oct 07, 2018 7:59 am
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 1163

Re: raspberry pi b+ old preloaded sd card

I would highly recommend starting with a a.) Normal Raspbian Stretch with desktop at: https://www.raspberrypi.org/downloads/raspbian/ b.) Or our clubs pre-configured Stretch variant for CAD/CAM, 3D printing, and Arduino dev : https://sourceforge.net/projects/micrometer-cnc-on-raspberry-pi/ Also, Etc...
by Joel_Mckay
Sun Oct 07, 2018 2:05 am
Forum: Advanced users
Topic: UART Interrupt
Replies: 1
Views: 408

Re: UART Interrupt

termios handles most serial communication settings... and blocking function calls to the buffer (wait for data, and flush buffer on key character like '\n' ): http://man7.org/linux/man-pages/man3/tcsetattr.3.html In general, most languages like Python simply wrap a C or C++ object with something lik...
by Joel_Mckay
Sat Oct 06, 2018 10:20 pm
Forum: Troubleshooting
Topic: Newest Kernel and / or Chromium broken
Replies: 50
Views: 5262

Re: Newest Kernel and / or Chromium broken

Just did some in-depth testing and comparison between my Raspberry Pi 3B and my Raspberry Pi 3B+. It is definitely the Kernel and the 3B+'s firmware, that's an absolute mess. I wasn't going to reply based on the bad karma behavior here, but our local group did encounter a vc4 glitch that would hang...
by Joel_Mckay
Sat Oct 06, 2018 9:27 pm
Forum: Troubleshooting
Topic: Can't install Chrome OS (FlintOS) on my Pi, Etcher won't create image, just wipes my SD card???
Replies: 7
Views: 1791

Re: Can't install Chrome OS (FlintOS) on my Pi, Etcher won't create image, just wipes my SD card???

That image is from 15/05/2017, and will likely not include the boot binary for some boards like pi3B+. When a disk is imaged some of the partition formats may not be recognized on Windows. Yet, there should be a small msdos compatible FAT32 boot partition with text files available for review. You wi...
by Joel_Mckay
Sat Oct 06, 2018 9:07 pm
Forum: Troubleshooting
Topic: DHT11 Humidity incorrect reading over 100%
Replies: 1
Views: 600

Re: DHT11 Humidity incorrect reading over 100%

I had commented about these DHT11 style sensors being unreliable many times, but perhaps some details are needed: * 1-wire timing jitters from the host cpu dynamic clock often corrupts the reads * those DHT often randomly stop working after about 2 days (need to power off to reset) * the DHT have po...
by Joel_Mckay
Fri Oct 05, 2018 6:21 am
Forum: Troubleshooting
Topic: Pi 3 Kernel panic-not syncing: VFS ony after 1 day
Replies: 3
Views: 414

Re: Pi 3 Kernel panic-not syncing: VFS ony after 1 day

Yes, but sometimes a forced disk check alone will not work if the utility is unreadable... hence... why we initially load from a ram disk (in /boot partition) based environment using busybox-static and e2fsck-static. #Some of the settings we used for normal mode root mounts, and note /etc/fstab flag...
by Joel_Mckay
Fri Oct 05, 2018 1:38 am
Forum: Troubleshooting
Topic: Pi 3 Kernel panic-not syncing: VFS ony after 1 day
Replies: 3
Views: 414

Re: Pi 3 Kernel panic-not syncing: VFS ony after 1 day

Cases I've seen: 1. some ebay Huawei dongles are modified to contain malware on the internal USBMSD drive (they are running their own internal linuxOS) 2. bad/worn-out/counterfeit-capacity-looping sdcard 3. rare, but kernel bugs do pop up every 5 years or so 4. power outage related damage... bad pow...
by Joel_Mckay
Fri Oct 05, 2018 1:08 am
Forum: Troubleshooting
Topic: Trouble running DHT22 Temperature/Humidity sensor at 5V
Replies: 11
Views: 3047

Re: Trouble running DHT22 Temperature/Humidity sensor at 5V

After testing several DHT22 sensors over the years I came to the conclusion they are unreliable in many situations. Have a look at the BME280 as it is a 3.3v i/o, regular i2c device, and does repeatable measurements. The footprint layout is odd, but the evaluation PCB modules are cheap. ;-) Good luc...

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