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by ghans
Fri Mar 29, 2019 8:53 am
Forum: Other
Topic: Running two different OS at the same time
Replies: 19
Views: 1714

Re: Running two different OS at the same time

QEMU+KVM should make this possible.

https://github.com/sakaki-/gentoo-on-rp ... -under-KVM

ghans
by ghans
Thu Mar 14, 2019 5:37 pm
Forum: Advanced users
Topic: Is it reliable to backup Raspi from remote?
Replies: 23
Views: 768

Re: Is it reliable to backup Raspi from remote?

The official SD Card Copier does not use dd because of this exact issue. It uses "cp" instead. In line with this, i would suggest using rsync to backup your Pi. rsync can transfer data over network by itself and also can be used over SSH for convenience. Obviously, i can't guarantee it works if both...
by ghans
Mon Mar 11, 2019 6:21 am
Forum: Raspbian
Topic: Large partition sizes, Raspbian and Windows
Replies: 49
Views: 1701

Re: Large partition sizes, Raspbian and Windows

Buy an USB SD card reader and a second SD card. Plug both into your running Pi.
Use the SD card copier. Use gparted to increase the size of the first partition.

Now you can use the second SD card on Windows and Linux.

ghans
by ghans
Tue Feb 26, 2019 6:23 am
Forum: Beginners
Topic: Raspberry Pi ADC Sampling Rate
Replies: 6
Views: 258

Re: Raspberry Pi ADC Sampling Rate

Inserting print statements into a tight loop is a universally bad idea. It will always lead to slowdown, but of course using Python + Raspberry Pi isn't going to help.

ghans
by ghans
Tue Feb 26, 2019 6:16 am
Forum: Device Tree
Topic: How to safely exit my program before KEY_POWER shutdown?
Replies: 6
Views: 632

Re: How to safely exit my program before KEY_POWER shutdown?

You need to write a signal handler for your program. SIGTERM is the one you should take care of first.

ghans
by ghans
Mon Feb 25, 2019 1:08 pm
Forum: Graphics, sound and multimedia
Topic: Read Audio Jack Output
Replies: 3
Views: 718

Re: Read Audio Jack Output

1) Use ALSA. I think you need to configure a plugin/module called "loopback". 2) Use PulseAudio, which is built on top of ALSA. I think you want to add a "null sink" and record from it. PulseAudio is supposedly more powerful - never had to configure it by hand, so cannot confirm or deny. Configuring...
by ghans
Sun Feb 17, 2019 9:57 am
Forum: Advanced users
Topic: Which Rasp for "pro" project?
Replies: 14
Views: 862

Re: Which Rasp for "pro" project?

You're supposed to design the motherboard yourself. The final size depends on your
skills and/or budget.

You can also order completely custom Raspberry Pis from element14. But their minimum order quantity is 3000-5000 units plus NRE costs.

ghans
by ghans
Tue Feb 12, 2019 8:05 am
Forum: General programming discussion
Topic: Controlling 100 LED's over TCP/IP between two Pi's
Replies: 8
Views: 815

Re: Controlling 100 LED's over TCP/IP between two Pi's

pigpio already supports remote control over a network. That might be easier than writing network code yourself.

ghans
by ghans
Mon Feb 11, 2019 6:32 am
Forum: Deutsch
Topic: Weswegen sollte ich den Pi User nutzen?
Replies: 5
Views: 739

Re: Weswegen sollte ich den Pi User nutzen?

Die Begründung für sudo ist die selbe wie für UAC unter Windows: ein Plus an Sicherheit. Die Existenz von root ist dem Administrator-Account unter Windows gleichzusetzen. Ein bösartiges Programm oder ein dummer Fehler kann dir dann das gesamte System zerschießen, wenn du die ganze Zeit als Admin/roo...
by ghans
Fri Feb 01, 2019 7:32 am
Forum: General discussion
Topic: understanding regulator frame work
Replies: 4
Views: 252

Re: understanding regulator frame work

Those APIs won't work. The firmware, not Linux, is in control of the PMIC (MXL7704) on the latest models (3B+, 3A+). Older models don't have a PMIC at all, they have fixed-voltage regulators.

ghans
by ghans
Thu Jan 24, 2019 7:47 am
Forum: General programming discussion
Topic: Creating a custom UI to boot up?
Replies: 5
Views: 765

Re: Creating a custom UI to boot up?

Which programming languages do you know ? Either way, booting is not instantaneous.
You probably want to play with the splashscreen settings ("plymouthd.conf") or code your own.

ghans
by ghans
Tue Jan 22, 2019 7:45 am
Forum: Beginners
Topic: Convert Audio/Video data through USB into binary stream at gpio pin
Replies: 3
Views: 157

Re: Convert Audio/Video data through USB into binary stream at gpio pin

For video, study the V4L2 API. For audio, study the ALSA API.

Please note those APIs are only directly exposed to C. For Python you will need wrappers
(multiple exist).


ghans
by ghans
Tue Jan 22, 2019 7:37 am
Forum: General discussion
Topic: MJPEG video
Replies: 3
Views: 188

Re: MJPEG video

The Raspberry Pi h.264 hardware video encoder does not support 4K. Running at full HD (1080 × 1920) is the maximum.

MJPEG doesn't seem to have the same restrictions.

ghans
by ghans
Tue Jan 22, 2019 7:23 am
Forum: Graphics programming
Topic: Best way to render video inside my program?
Replies: 7
Views: 1052

Re: Best way to render video inside my program?

Most likely, the easiest way is using omxplayer from your program. omxplayer allows control and querying via the MPris2 protocol.

ghans
by ghans
Sat Jan 19, 2019 10:07 am
Forum: Advanced users
Topic: Virtual com port drivers?
Replies: 9
Views: 643

Re: Virtual com port drivers?

Those devices are created by "udev". USB devices become plug-and-play thanks to udev, too.

ghans
by ghans
Fri Jan 18, 2019 7:06 am
Forum: Beginners
Topic: Convert Audio/Video data through USB into binary stream at gpio pin
Replies: 3
Views: 157

Re: Convert Audio/Video data through USB into binary stream at gpio pin

Which programming languages do you know ?

ghans
by ghans
Wed Jan 02, 2019 3:25 am
Forum: Deutsch
Topic: RaspberryPI 1 b+ als tastatur?
Replies: 2
Views: 292

Re: RaspberryPI 1 b+ als tastatur?

Keines der B Modelle kann als Tastatur fungieren. Die Zero - und A Modelle können es hingegen schon - sogar recht einfach, vorausgesetzt du sprichst flüssig "Linux". Die B Modelle haben alle einen Ethernet-USB-Hub-Combochip der alle Ports in den Hostmodus zwingt. Beim Rest gibt es eine direkte Verbi...
by ghans
Tue Dec 25, 2018 6:13 pm
Forum: Graphics, sound and multimedia
Topic: Slightly glitchy sound producing tones via GPIO pins
Replies: 7
Views: 448

Re: Slightly glitchy sound producing tones via GPIO pins

The Raspberry Pi has a PWM peripherial which sidesteps timing issues. I believe that it is available through WiringPi.

Being able and willing to interrupt processes by force is a feature of all so-called preemptive operating systems like Windows, Linux and Mac OS X.

ghans
by ghans
Wed Dec 19, 2018 7:35 am
Forum: Advanced users
Topic: Raspivid + WebRTC + getUserMedia() = ?
Replies: 3
Views: 784

Re: Raspivid + WebRTC + getUserMedia() = ?

Try loading the official V4L2 driver:

Code: Select all

sudo modprobe bcm2835-v4l2
No idea if it supports two cameras. You should play around with v4l2-ctl (part of v4l-utils).

ghans
by ghans
Wed Dec 19, 2018 7:22 am
Forum: Raspbian
Topic: Launch a .jar with GUI on Raspbian Stretch Lite boot
Replies: 4
Views: 1096

Re: Launch a .jar with GUI on Raspbian Stretch Lite boot

You can try to install the X server + openbox + lightdm on Raspbian lite to fix this:

Code: Select all

sudo apt-get install xserver-xorg-core xserver-xorg-input-all xserver-xorg-video-fbdev libx11-6 x11-common x11-utils x11-xkb-utils x11-xserver-utils xterm lightdm openbox
ghans
by ghans
Fri Dec 14, 2018 5:59 am
Forum: Other programming languages
Topic: Chromium and Raspbian lite, programmatic control
Replies: 4
Views: 965

Re: Chromium and Raspbian lite, programmatic control

Professional browser automation is done with Selenium and the WebDriver protocol. The latter is already supported by Chromium AFAIK. I am not convinced that an embedded webserver isn't the cleanest solution. The seperation between server and client is a positive, since you normally want to swap the ...
by ghans
Wed Dec 12, 2018 5:44 am
Forum: Other projects
Topic: Developer new TFT LCD driver for Linux RPI
Replies: 6
Views: 471

Re: Developer new TFT LCD driver for Linux RPI

Have a look at "tinydrm":
https://github.com/notro/tinydrm/wiki

tinydrm was explicitly designed for writing simpler LCD drivers, especially on the Raspberry Pi.

ghans
by ghans
Fri Dec 07, 2018 6:30 am
Forum: Troubleshooting
Topic: Data Retrieval from corrupted file system raspberry pi SD card
Replies: 5
Views: 364

Re: Data Retrieval from corrupted file system raspberry pi SD card

@anaTech Why are you working with /dev/mmcblk0pXX ? That is obviously the internal SD card which is currently in use. The SD card in the reader should be called differently. To make sure, unplug the reader with card and replug it. Now sudo dmesg | tail should show you the name of the external SD car...
by ghans
Wed Dec 05, 2018 9:04 am
Forum: Troubleshooting
Topic: Data Retrieval from corrupted file system raspberry pi SD card
Replies: 5
Views: 364

Re: Data Retrieval from corrupted file system raspberry pi SD card

Do not try to upload photos here (heavy filesize restrictions), use imgur.com instead. What you want to do is following: 1) Make an image backup of the old card with dd (You need enough free space). sudo dd if=/dev/sda of=/path/to/imgfile.img bs=4K If you don't have enough space you can skip to step...
by ghans
Wed Dec 05, 2018 8:28 am
Forum: Python
Topic: Display simple image on GPIO screen
Replies: 12
Views: 1134

Re: Display simple image on GPIO screen

You seem to be using devicetree overlays, which is excellent.
I propose that you use guizero.

guizero is a GUI library specially written for beginners.
It comes very close to your pseudo-code because of this.

https://lawsie.github.io/guizero/images/

ghans

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