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by karrika
Tue Apr 24, 2018 3:20 am
Forum: Beginners
Topic: Smart Display for Elderly
Replies: 6
Views: 165

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: 382

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: 10
Views: 226

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: 77

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.
by karrika
Mon Apr 16, 2018 10:58 am
Forum: Graphics, sound and multimedia
Topic: fruitbox MP3 jukebox
Replies: 540
Views: 37034

Re: fruitbox MP3 jukebox

One suggestion to the TouchOne skin. Setting the volume is most likely done at the amplifier anyway. So I wonder if it could be possible to have a variant of this skin where the volume button would be replaced by a Genre button? Hi Should be just a matter of removing the volume indicator bitmap obj...
by karrika
Sun Apr 15, 2018 1:16 pm
Forum: Graphics, sound and multimedia
Topic: fruitbox MP3 jukebox
Replies: 540
Views: 37034

Re: fruitbox MP3 jukebox

One suggestion to the TouchOne skin.

Setting the volume is most likely done at the amplifier anyway. So I wonder if it could be possible to have a variant of this skin where the volume button would be replaced by a Genre button?
by karrika
Thu Apr 12, 2018 5:02 am
Forum: General discussion
Topic: Question on pull up resistor
Replies: 5
Views: 189

Re: Question on pull up resistor

In the example you posted the built-in resistor is set to pull down.

So if the pin is set to input at startup there is still a pull down resistor that does not trigger the relay.

If the pin is then set as an output it will be at whatever state you program it to be.
by karrika
Thu Apr 12, 2018 3:02 am
Forum: Gaming
Topic: Interactive novel / a text-adventure game for the Rpi3 to download.
Replies: 3
Views: 232

Re: Interactive novel / a text-adventure game for the Rpi3 to download.

Thanks for sharing. I have to try this out. On the Atari retro site there is another initiative to use Google Blockly for creating interactive novels. Last year I wrote a novel for Atari Lynx on it and there exists also a Blockly compiler for Sega. http://atariage.com/forums/topic/272139-always-wint...
by karrika
Mon Apr 09, 2018 8:38 am
Forum: Automation, sensing and robotics
Topic: ideas to secure the pi-based IOT even further
Replies: 12
Views: 348

Re: ideas to secure the pi-based IOT even further

If you are really planning a thesis out of this topic I suggest going into details. The iproute is one technology. You can also add a list of allowed IP servers to connect to for delivering the goods to the server from the IoT node. MAC filtering could also be implemented. Then we have different tec...
by karrika
Sun Apr 08, 2018 11:18 am
Forum: Automation, sensing and robotics
Topic: ideas to secure the pi-based IOT even further
Replies: 12
Views: 348

Re: ideas to secure the pi-based IOT even further

The most important thing is to close all ports on the Pi. could you explain how to do this ?? You need to use a package called iptables. sudo apt-get install iptables After this you write an extremely defensive set of rules. Like: iptables.sh: #!/bin/sh # ===========================================...
by karrika
Sun Apr 08, 2018 7:07 am
Forum: Automation, sensing and robotics
Topic: ideas to secure the pi-based IOT even further
Replies: 12
Views: 348

Re: ideas to secure the pi-based IOT even further

The most important thing is to close all ports on the Pi. For IOT the principle should be that the IOT device connects to some connection point to upload/fetch data. There should be no attack surface on the IOT itself. This is how Microsoft IOT works also. So you never connect to your IOT thing. The...
by karrika
Thu Apr 05, 2018 11:06 pm
Forum: Media centres
Topic: Dead Simple MP3 Player For Grandma
Replies: 4
Views: 3284

Re: Dead Simple MP3 Player For Grandma

Why not just grab fruitbox? Grandma remembers how to use it from her childhood :D

Image
by karrika
Thu Apr 05, 2018 9:22 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B with 7" screen power issues (continued).
Replies: 15
Views: 300

Re: Raspberry pi 3B with 7" screen power issues.

Most LED snakes and RGB LED panels are powered this way. Feeding more amps through an USB cable sounds more difficult to me... But of course you could try to feed the 7" display from one PSU and the rest from another. It is the best bet I can think about right now as you don't have to build any extr...
by karrika
Thu Apr 05, 2018 8:44 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B with 7" screen power issues (continued).
Replies: 15
Views: 300

Re: Raspberry pi 3B with 7" screen power issues.

I looked at the schematics. There is a 500mA fuse called R1 on the board that provides the power to the LED's. You could take away the fuse and build a separate LED power supply for feeding the lights.
by karrika
Thu Apr 05, 2018 8:32 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B with 7" screen power issues (continued).
Replies: 15
Views: 300

Re: Raspberry pi 3B with 7" screen power issues.

I am sure you can put more power on it. But I would suggest turning SPI off from raspi-config. It should also improve the sound quality. I cannot imagine why anyone would like to switch large currents on/off on the same board where you try to run 4 microphones. This sounds insane. It must be some ma...
by karrika
Thu Apr 05, 2018 8:18 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B with 7" screen power issues (continued).
Replies: 15
Views: 300

Re: Raspberry pi 3B with 7" screen power issues.

Terve (semi-international forum..)

The maximum power per LED is 0.2W to 1W(APA102C datasheet). With 12 LED's you eat up 12W. That alone drains more than 2 Amps from the PSU.
by karrika
Thu Apr 05, 2018 8:07 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B with 7" screen power issues (continued).
Replies: 15
Views: 300

Re: Raspberry pi 3B with 7" screen power issues.

Hi again, The only difference with your and my setup is the type of the HAT board. I am using AudioInjector HAT + DiscoHAT. So 2 boards. No yellow symbol using a single official PSU. No yellow symbol using a standard LG USB charger. No yellow symbol using a standard Nokia phone charger. Yellow symbo...
by karrika
Thu Apr 05, 2018 12:04 pm
Forum: Advanced users
Topic: Documentation bugs: RPi2&3 GPIO electrical specs
Replies: 113
Views: 7965

Re: Documentation bugs: RPi2&3 GPIO electrical specs

Almost every user who is just trying to add a push button is hit with the fact that the GPIO pins have a grey area of voltages where the value oscillates. It has been well documented by paulv in this forum. https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=133740 I assume that understanding t...
by karrika
Thu Apr 05, 2018 8:09 am
Forum: Advanced users
Topic: Documentation bugs: RPi2&3 GPIO electrical specs
Replies: 113
Views: 7965

Re: Documentation bugs: RPi2&3 GPIO electrical specs

Thank you for the BCM 14, BCM 15 info. I am probably doing all sensitive stuff where resonance matters on a HAT board and feed the data to the pins using a Schmitt trigger. This should also cover for the probable impedance drift caused by temperature. I actually thought of a writing a version of Tap...
by karrika
Tue Apr 03, 2018 5:11 am
Forum: Advanced users
Topic: Documentation bugs: RPi2&3 GPIO electrical specs
Replies: 113
Views: 7965

Re: Documentation bugs: RPi2&3 GPIO electrical specs

+1 Almost every user who is just trying to add a push button is hit with the fact that the GPIO pins have a grey area of voltages where the value oscillates. It has been well documented by paulv in this forum. https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=133740 I assume that understanding...
by karrika
Sun Apr 01, 2018 8:08 pm
Forum: Raspbian
Topic: A Light OS for PI Zero / Browser
Replies: 12
Views: 524

Re: A Light OS for PI Zero / Browser

I am currently using PiZero to run sound and lights in a theatre. No desktop - only Qt5.

Another pi3 running fruitbox OpenGL from the shell.

Third pi running RPi-InfoScreen directly from Kivy.

All these run perfectly alone and have problems running from a desktop.
by karrika
Sat Mar 31, 2018 5:05 am
Forum: Official Foundation Display
Topic: Raspberry pi 3B + 7'' official touch screen power supply
Replies: 21
Views: 243

Re: Raspberry pi 3B + 7'' official touch screen power supply

Buy a good USB cable intended for powering things. You want thick copper cables - not thin aluminium cables with copper coating.

Avoid DC buck converters. They produce a lot of noise that affects the touch screen. It becomes sluggish and non responsive.
by karrika
Sat Mar 31, 2018 4:52 am
Forum: Graphics, sound and multimedia
Topic: fruitbox MP3 jukebox
Replies: 540
Views: 37034

Re: fruitbox MP3 jukebox

This is what happens with bad cooling. You need to get the heat to transfer out of the chip. With the Flirc case the case is conductive and the heat is transferred to the entire case heating it up. In an optimum system the heat is spread evenly and the CPU is at case temperature. Full screen GPU tak...
by karrika
Fri Mar 30, 2018 10:39 am
Forum: Troubleshooting
Topic: Simple fix to broken SD connector
Replies: 1
Views: 72

Simple fix to broken SD connector

I accidentally broke my PiZero SD connector. Fortunately there is test pads available for soldering in a full size MicroSD adapter.

Image

It may not be as pretty as the original one. But in case you have an extra MicroSD adapter the fix is free.
by karrika
Thu Mar 29, 2018 1:48 pm
Forum: General discussion
Topic: pi3: how to avoid "any" radiation?
Replies: 43
Views: 1345

Re: pi3: how to avoid "any" radiation?

If you are really into low radiation devices then have a look at small microcontrollers that can turn themselves off to a sleep mode. I would also suggest looking into very low power chips. Arduino comes to mind... The best design does not produce electric noise at all. But creating a noiseless desi...

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