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by altosack
Thu Jul 26, 2018 5:52 am
Forum: Troubleshooting
Topic: Certain screens not working
Replies: 2
Views: 206

Re: Certain screens not working

The raspberry pi doesn't have autodetect support for screens greater than 1080p60. You can get it do display up to 2160p24 (or probably about 1440p40) by tweaking parameters manually, but it will not autodetect anything above 1080p. I'm not aware of a post directly dealing with 1440p, but if you rea...
by altosack
Fri Mar 16, 2018 5:33 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 925
Views: 455324

Re: STICKY: The I2S sound thread.

I have an I2S amp HAT (Adafruit speaker bonnet) on a Pi Zero W, headless; when I play anything (speaker-test, aplay, omxplayer, mpg123), I get an initial pop, so I know I have power, the correct device, driver, etc., but then there is no output with any of them. Any ideas ? As far as I know, it's no...
by altosack
Thu Oct 26, 2017 8:21 pm
Forum: Advanced users
Topic: Video decode ability?
Replies: 1
Views: 395

Re: Video decode ability?

The VC4 in the pi will not decode a 4k video at any frame rate; it is hardware limited to 2048 pixels. It will display a 4k desktop, and decode 1920x1080 on that desktop, but I don't think it's capable of 60 Hz at that resolution; I'm not sure what frame rate is possible, but I have watched 1920x108...
by altosack
Thu Oct 26, 2017 7:38 pm
Forum: Graphics, sound and multimedia
Topic: Different resolution between DPI and VNC Remote Desktop
Replies: 2
Views: 938

Re: Different resolution between DPI and VNC Remote Desktop

See this thread : viewtopic.php?f=66&t=161341#p1044414

In short, use the service mode of VNC, and add "-geometry HRESxYRES" to the vncserver command; e.g.,

Code: Select all

vncserver -geometry 1280x720
by altosack
Fri Oct 20, 2017 4:33 am
Forum: General discussion
Topic: Why do new forum members not come back?
Replies: 42
Views: 6594

Re: Why do new forum members not come back?

Yes, looking for new/unread posts takes ages. I do find it strange that individual experiences on the forum are all over the place. I almost always use "unread posts" from the quick links, and it takes about 2 seconds. I use a 4K screen as a daily desktop (I also have an x86/debian machine that I u...
by altosack
Sat Oct 07, 2017 2:11 am
Forum: Raspbian
Topic: Much slower desktop performance at 4K on Stretch vs. Jessie
Replies: 0
Views: 1032

Much slower desktop performance at 4K on Stretch vs. Jessie

I have run my Pi 3 with a 4K (24 Hz) desktop ever since I got it (about April '16), and it has had what I would call acceptable performance. No, I don't do gaming, but full-screen LibreOffice Draw, as well as the normal Chromium and edit/compile/flash/run cycles ad infinitum, works just fine. At the...
by altosack
Wed Oct 04, 2017 10:07 am
Forum: Automation, sensing and robotics
Topic: Reading mV signals from RPi3
Replies: 2
Views: 854

Re: Reading mV signals from RPi3

What kind of accuracy do you need ? From what you've said about your ADS1115, you will have a relative accuracy of about 10 uV (1% at 1 mV and 0.1% at 10 mV), which sounds pretty good to me. If you need to increase the relative accuracy, I wouldn't use an external gain amplifier; I would first decre...
by altosack
Sun Jun 25, 2017 5:16 am
Forum: General discussion
Topic: Can Pi zero wifi do 2K HDMI?
Replies: 11
Views: 1985

Re: Can Pi zero wifi do 2K HDMI?

Yes, 1920x1080 @ 60 Hz is its rated resolution. If you are just concerned with displaying images, and not using it as a desktop, then 4k24 (3840x2160 @ 24 Hz) output is possible; search the board for a some very interesting threads about it.
by altosack
Thu Jan 12, 2017 2:22 pm
Forum: Advanced users
Topic: Firefox acts like it's running on a small screen device
Replies: 11
Views: 2209

Re: Firefox acts like it's running on a small screen device

Dougie, the advantage to using Firefox over Chrome is that you can open about three times as many tabs before you run out of memory. I usually have one tab open in Chrome if I want to watch a video (which is much better in Chrome than Firefox), and the rest in Firefox, which works well for me. I use...
by altosack
Sat Dec 31, 2016 7:48 pm
Forum: General discussion
Topic: My Raspberry pi 2 B is overheating !
Replies: 9
Views: 1662

Re: My Raspberry pi 2 B is overheating !

Hey, all you naysayers, I had exactly the symptoms he described with my Pi A, including the main chip getting too hot to touch (even just a tap), and after fixing what I assume was a short in the USB connection of the wifi dongle, the pi was fine (just for grins, I'm using it to type this, even thou...
by altosack
Sat Dec 31, 2016 4:52 pm
Forum: General discussion
Topic: My Raspberry pi 2 B is overheating !
Replies: 9
Views: 1662

Re: My Raspberry pi 2 B is overheating !

It sounds like you have a defective USB plug. This happened to me with a wifi dongle on a Pi, and it caused the same problems that you're describing until I pulled it out slightly. I didn't want to depend on that, so I threw it away after I couldn't figure out how to bend it to keep it from happening.
by altosack
Wed Nov 23, 2016 8:25 pm
Forum: Advanced users
Topic: .
Replies: 18
Views: 3052

Re: Running Assembly code on the PI

Typically:- as hello.s -o hello.o ld hello.o -o hello The GCC compiler can also assemble stuff (well it will just call "as" for you), and will do the link for you. gcc hello.s -o hello I think it's a good habit to get into to call all of your assembly files that you actually write .S rather than .s...
by altosack
Mon Oct 17, 2016 2:16 am
Forum: General discussion
Topic: Kali Linux on Rasberry Pi 3B
Replies: 7
Views: 1787

Re: Kali Linux on Rasberry Pi 3B

You cannot type $ sudo apt-get install upgrade The correct forms are: $ sudo apt-get update $ sudo apt-get upgrade $ sudo apt-get dist-upgrade $ sudo apt-get install <package-name> An example of the last command above: $ sudo apt-get install kodi update renews the information about what packages are...
by altosack
Thu Oct 06, 2016 7:34 am
Forum: Raspbian
Topic: Raspbian with RPI Desktop and RealVNC
Replies: 69
Views: 54359

Re: Pixel and RealVNC

I have no display attached to the RPi, but I don't want a virtual desktop? Why is that? It sounds like what I would want. What's it for? Is a virtual desktop an *additional* desktop, ie. there is the overhead to run normal desktop (even though there is nothing plugged in), plus the overhead to run ...
by altosack
Wed Oct 05, 2016 12:51 pm
Forum: Raspbian
Topic: Raspbian with RPI Desktop and RealVNC
Replies: 69
Views: 54359

Re: Pixel and RealVNC

Barry4679 wrote:... if I ran vncserver, but that ignored the changes that I had made to /boot/config.txt to adjust resolution to suit my PC's screen.
When you run vncserver, add "-geometry XRESxYRES".
E.g.: vncserver -geometry 1024x768
by altosack
Fri Sep 16, 2016 3:02 am
Forum: Raspbian
Topic: Login commands?
Replies: 7
Views: 1248

Re: Login commands?

For login shells:
/etc/profile
$HOME/.profile

For non-login (interactive) shells:
/etc/bash.bashrc
$HOME/.bashrc
by altosack
Sat Apr 09, 2016 6:07 pm
Forum: Troubleshooting
Topic: GEDIT issue
Replies: 5
Views: 1231

Re: GEDIT issue

I used to use gedit for many years, but I've had problems with it on Raspian. I switched to pluma (which I believe is a derivative, and it has all the features I need), and I've never looked back.
by altosack
Sun Apr 03, 2016 6:27 pm
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi and 4k @ 15Hz
Replies: 123
Views: 164739

Re: Raspberry Pi and 4k @ 15Hz

For regular xorg, which file did you put the Rotate mod in? When I tried to replicate it, it seems a little more involved than I remember. I had to put the following in /etc/X11/xorg.conf, which does not exist by default: Section "Device" Identifier "4k" Driver "fbdev" Option "Rotate" "CCW" Option ...
by altosack
Sat Apr 02, 2016 5:02 pm
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi and 4k @ 15Hz
Replies: 123
Views: 164739

Re: Both 4k and portrait mode

Transposing the display is an expensive operation at 1080p. I think there is no chance at 4K. I assume you mean that there's no chance of the GPU doing it, because it has been done with the X framebuffer. The "magic mirror" guy did it, I did it, and others have done it. I use xorg.conf (Option "Rot...

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