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by karrika
Fri Nov 16, 2018 9:36 pm
Forum: Other projects
Topic: Using PI for ship tracking via API
Replies: 3
Views: 492

Re: Using PI for ship tracking via API

I have been using a fairly simple system for a long time. Collect lat/lon from each vessel to a text file every 5 minutes. Use rsync to send the file to shore every hour. The name of the file is the date. When the date changes the data starts going to a new file. You can easily monitor the files dur...
by karrika
Mon Oct 22, 2018 7:21 pm
Forum: Automation, sensing and robotics
Topic: Connecting Pi to reed switches on long cable
Replies: 10
Views: 914

Re: Connecting Pi to reed switches on long cable

Using GPIO lines for detecting a reed relay will have spurious noise on the line. Your best bet is to read the data a few times before accepting the value. read_relay() sleep 50ms read_relay() sleep 50 ms read_relay() If all these read_relay()'s had the same value you can rely on it. If the values w...
by karrika
Thu Aug 16, 2018 8:39 am
Forum: Other projects
Topic: what to do with an old police scanner.
Replies: 11
Views: 994

Re: Not sure where else to ask this....

A Pi has audio out. But you may need a little amplification to feed the sound to the speakers. Buttons can be connected to GPIO pins for detecting when you press them. The dials could be read with some electronics magic. LED's can be controlled by a Pi. The question remains... What should it become?...
by karrika
Fri Aug 03, 2018 4:46 am
Forum: Graphics, sound and multimedia
Topic: fruitbox MP3 jukebox
Replies: 784
Views: 90824

Re: fruitbox MP3 jukebox

My fruitbox starts at boot. It is a Pi3 plus 7" touch screen. At the end of my .bashrc I just added: cd /home/pi/rpi-fruitbox sudo ./fruitbox --cfg skins/TouchOne/fruitbox.cfg And of course I choose automatic log-in at startup from raspi-config so that I don't have to enter a password. And choose to...
by karrika
Sun Jul 29, 2018 4:45 am
Forum: Graphics, sound and multimedia
Topic: Recommendations for a little hdmi monitor
Replies: 7
Views: 409

Re: Recommendations for a little hdmi monitor

I am using the same LCD screen with two add on cards as well. The solution for me was to buy a HAT stack board from Pimoroni. You get both touch screen and can use external cards. I decided to go with PiZero as it dud not have a 49 pin connector. So I also soldered HAT connector on the Pi and could ...
by karrika
Sun Jul 29, 2018 4:33 am
Forum: Advanced users
Topic: New RT (Real Time) kernel branch
Replies: 31
Views: 6932

Re: New RT (Real Time) kernel branch

For high speed streaming I always use 3 buffers. One buffer for reading in data. When it is full continue with buffer 2. When it is full continue with buffer 3. Once a buffer is full start processing it. Stream out processed buffers in the same fashion as while reading. All these 3 buffers are share...
by karrika
Mon Jul 09, 2018 11:52 am
Forum: Graphics programming
Topic: Tilengine - 2D retro graphics library with raster effects
Replies: 21
Views: 9411

Re: Tilengine - 2D retro graphics library with raster effects

Thanks! I did a small test run on it on a 64 bit Ubuntu. The install fails because the path for the library is Tileengine/lib when the install script expects the library to be at Tileengine/linux_x86_64/lib. On the other hand the C-compiled versions seem to dump core with Program received signal SIG...
by karrika
Wed Jun 27, 2018 4:08 am
Forum: Graphics programming
Topic: Vulkan, OpenGL or OpenGLES
Replies: 9
Views: 1335

Re: Vulkan, OpenGL or OpenGLES

Blender is a long time friend. In the early days I was adding money to buy it free when the original company went bankrupt. Today I do all my 3D print designs with it. But you can also export your 3D spaceships as Blender objects to be rendered by your Python code. Kivy has a nice piece of code for ...
by karrika
Mon Jun 25, 2018 5:58 pm
Forum: Beginners
Topic: Transfer real-time video over 4G cellular network
Replies: 9
Views: 415

Re: Transfer real-time video over 4G cellular network

I have been using the package https://elinux.org/RPi-Cam-Web-Interface for a long time. It allows you to match your video quality and frame rates to your data network. It also has automatic motion detection so you can get video started when it detects something moving. And you can take very high res...
by karrika
Sun Jun 24, 2018 9:35 am
Forum: Graphics programming
Topic: Vulkan, OpenGL or OpenGLES
Replies: 9
Views: 1335

Re: Vulkan, OpenGL or OpenGLES

Vulcan is more for controlling the GPU in an optimal way. So you get the most out of the limited hardware by taking this route. It is also the hardest. It is very verbose and you have to write tons of stuff just to draw a triangle. OpenGL on the other hand is about defining 3D graphics. So it is muc...
by karrika
Tue May 22, 2018 7:34 am
Forum: General discussion
Topic: Multiple framebuffer support - testers wanted
Replies: 8
Views: 714

Re: Multiple framebuffer support - testers wanted

I believe that the natural setup would be to have a 7" touch screen for entering commands and use a HDMI screen for output. Actually I have already tried this with omxplayer as you can re-direct the video to the 2nd screen. There is a few applications where I see this as a very good thing. The QLC+ ...
by karrika
Sun May 20, 2018 4:55 am
Forum: C/C++
Topic: Increase GPIO toggle frequency
Replies: 24
Views: 1646

Re: Increase GPIO toggle frequency

I am a bit puzzled about why you want to bit-bang the serial data instead of just using MOSI and SCLK from the SPI interface? It does exactly the same thing. Just a bit faster. I could be wrong here. This is the way we control rgb snakes and rgb panels in QLCplus
by karrika
Thu May 17, 2018 9:19 am
Forum: Graphics, sound and multimedia
Topic: fruitbox MP3 jukebox
Replies: 784
Views: 90824

Re: fruitbox MP3 jukebox

fruitbox wrote:
Tue May 15, 2018 9:34 pm
Release v1.12 teaser...
I love it!

The format conversion is no problem. Currently I have a few music clips with video that I would LOVE to play. Combining this with normal music in jukebox is really appreciated.
by karrika
Fri May 11, 2018 4:36 am
Forum: General discussion
Topic: Social project
Replies: 2
Views: 228

Re: Social project

While using a Pi may sounds like a good idea I believe you need electricity and internet to make this work.

Perhaps airbnb and a mobile phone would be the solution?
by karrika
Wed May 09, 2018 3:24 am
Forum: Other projects
Topic: Secure Enclosure for Raspberry Pi - Physical Security
Replies: 3
Views: 951

Re: Secure Enclosure for Raspberry Pi - Physical Security

Actually you could leave the USB ports open and disable USB handling from /etc/udev by adding a prohibitive rule. It is also possible to enable just some USB keyboard with a certain serial identification. In the style /etc/udev/rules.d/01-disable.rules ACTION=="add", SUBSYSTEMS=="usb", RUN+="/bin/sh...
by karrika
Mon May 07, 2018 12:10 pm
Forum: Other projects
Topic: Secure Enclosure for Raspberry Pi - Physical Security
Replies: 3
Views: 951

Re: Secure Enclosure for Raspberry Pi - Physical Security

Flirc top plus custom 3D printed bottom that also covers SD card and USB ports.
by karrika
Sat May 05, 2018 9:42 am
Forum: General discussion
Topic: Cryogenic Raspberry Pi & Camera CERN schematic
Replies: 15
Views: 965

Re: Cryogenic Raspberry Pi & Camera CERN schematic

The Pi is not really a good device for cryogenic overclocking. Years ago I tried with a static chip that contained no timers or dynamic delays. You could submerge a Transputer in liquid nitrogen and run it with 10 times higher clock speed. But the Transputer also contained RAM and communication insi...
by karrika
Fri May 04, 2018 8:57 pm
Forum: Assistive technology and accessibility
Topic: Smart Display for Elderly
Replies: 8
Views: 3411

Re: Smart Display for Elderly

This is not a difficult project. My mother has moderate dementia and lives with and I made her a simple display with a used 19" LED TV, a Pi3, and MagicMirror2 software (https://magicmirror.builders/). MM2 is relatively simple to set up and has several built in modules and numerous 3rd party module...
by karrika
Sun Apr 29, 2018 9:08 am
Forum: Beginners
Topic: First Pi Project - Multi-Timezone Clock
Replies: 19
Views: 1013

Re: First Pi Project - Multi-Timezone Clock

If you connect the display in a matrix and switch the segments on/off they are bound to flicker. Search for the frequency in the driver and try to change that to see if you can increase it.
by karrika
Sat Apr 28, 2018 2:22 pm
Forum: Python
Topic: Installing Program requiring Python 2.7 when default is 3.x
Replies: 17
Views: 2206

Re: Installing Program requiring Python 2.7 when default is 3.x

I just noticed that the latest Ubuntu 18.04 LTS for x86 only has python3 installed. So slowly the python2 is being phased out.
by karrika
Sat Apr 28, 2018 8:24 am
Forum: Beginners
Topic: How to watch live video on the RPi
Replies: 1
Views: 177

Re: How to watch live video on the RPi

The Pi camera that connects with a flat cable to the Pi directly can export its stream to a web page. If the web page is at localhost then you can open the web browser in teamviewer and watch the video. This may work. You can also connect with ssh and forward the web page to your home computer. The ...
by karrika
Tue Apr 24, 2018 3:20 am
Forum: Assistive technology and accessibility
Topic: Smart Display for Elderly
Replies: 8
Views: 3411

Re: Smart Display for Elderly

This is one application I have thinking about for a very long time. Creating some kind of interface that looks very physical (intuitive) could be the way to go. I am thinking about communicating with pictures. One framework that could be extended to do the job is the RPi-InfoScreen project. There is...
by karrika
Sun Apr 22, 2018 4:51 pm
Forum: General discussion
Topic: Power
Replies: 14
Views: 639

Re: Power

The Pi is a bit sensitive to ripple as well. I have not been able to provide good enough power from ebay DC buck converters. The current is ok and voltage also. But some additional peripherals as 7" Official display touch screen gets very insensitive when the current has a high frequency ripple on t...
by karrika
Sun Apr 22, 2018 4:40 pm
Forum: Beginners
Topic: First Pi Project - Multi-Timezone Clock
Replies: 19
Views: 1013

Re: First Pi Project - Multi-Timezone Clock

Are you going to leave the LED's visible as they are or do you plan to use some decorative front plate?

You already seem to master the technical details.
by karrika
Sat Apr 21, 2018 10:55 am
Forum: Graphics, sound and multimedia
Topic: Introducing the AudioInjector Ultra
Replies: 1
Views: 264

Re: Introducing the AudioInjector Ultra

Wow. You are really creating new great audio cards. I am still using the previous PiZero style card at the theater. No hiccups, no problems. It just sounds great.

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