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by Tzarls
Thu Mar 28, 2019 12:17 pm
Forum: General discussion
Topic: Pi 4 questions
Replies: 166
Views: 6582

Re: Pi 4 questions

Since the only thing we know for sure about the Pi4, or Pi5, or Pi6 is that price will be 35$...can I pre-order right now? Coumt me as first in line, others can stand behind me. 😁
by Tzarls
Mon Mar 18, 2019 2:45 am
Forum: General programming discussion
Topic: Mixing C and assembly?
Replies: 18
Views: 639

Re: Mixing C and assembly?

A few years ago I got involved in porting some software to the Raspberry Pi, and had to investigate how function arguments and returns work in assembly - learnt a lot about r, s and d registers. The whole discussiones and work progress is documented here: https://www.gamedev.net/forums/topic/634187-...
by Tzarls
Sat Mar 16, 2019 10:50 pm
Forum: General discussion
Topic: design of a generic raspberry pi 3 form factor open source notebook cabinet?
Replies: 18
Views: 905

Re: design of a generic raspberry pi 3 form factor open source notebook cabinet?

Such "cabinet" exists:

http://www.wawaperu.org/

I've seen it working with a Raspberry Pi and at least one iother kind of SBC.
by Tzarls
Wed Jan 16, 2019 10:48 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3386

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

Another idea, this time with some hardware hacking: Could you just modify the power adapter in such a way that when it is connected to the load (the RPi) it slowly charges some kind of device (a capacitor?) and only after that it powers its main device (the RPi)? By delaying the reboot process the R...
by Tzarls
Wed Jan 16, 2019 12:40 am
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3386

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

Ok, here's the solution you've been looking for, without having to redesign SOCs or spend millions. You just need to design a new case based on this guidelines: The case should be closedd and cover the SD slot with some kind of lid. When the lid is opened it activates some mechanism that moves some ...
by Tzarls
Wed Dec 26, 2018 5:42 am
Forum: Off topic discussion
Topic: Merry Xmas RasberryPi!
Replies: 21
Views: 1808

Re: Merry Xmas RasberryPi!

What are we all eating today? Well... Just came back from having a late Festivus dinner at TGI Friday's... That would be ribs for me, some chicken for the kids and lemonade and chicha morada for drinks... And yes, it's summer solstice around here. Live long and prosper, and may the schwatrz be with...
by Tzarls
Sat Nov 24, 2018 3:41 am
Forum: Off topic discussion
Topic: My 1st ever dead Pi.
Replies: 14
Views: 2334

Re: My 1st ever dead Pi.

You must have tripped your Pi's polyfuse, maybe when testing voltages. Now it has reset, that's why it is working again. I had something like this happen once to one of my Raspis, one that was doing almost nothing, just displaying photos over and over. One day it was dead. After a coupe of days it w...
by Tzarls
Thu Aug 02, 2018 5:30 am
Forum: General discussion
Topic: RPI 3B+ reports incorrect clockspeed. Video
Replies: 60
Views: 3122

Re: RPI 3B+ lies about it's clockspeed. Video

One Meg just does not cut it with modern browsers, even with all sorts of ad and script blockers and a pi-hole up front in a separate Rpi. The 3B doesn't just slow down when hot...it 'effin quits. You mean 1 Gig, right? FWIW, I have a RPi3B in an AIY Voice V1 - no heatsink, locked in a cardboard bo...
by Tzarls
Tue Jul 24, 2018 5:19 pm
Forum: Off topic discussion
Topic: What was your 1st game?
Replies: 49
Views: 16033

Re: What was your 1st game?

My first computer game must have been one called "chopper" where you controled a helicopter and had to manuever through caves and rescue people from the top of buildings. All graphics were done with text characters. As far as I remember this was on an Olivetti machine, like 200 years ago. I don't re...
by Tzarls
Fri Jun 29, 2018 9:25 pm
Forum: Beginners
Topic: virtual keyboard for touch screen?
Replies: 49
Views: 8022

Re: virtual keyboard for touch screen?

ok, I give up with Jessie Don't. For downloading I usually "cheat" - I download the package using my Windows Pc and then transfer the file to the Pi (mainly because I use Windows to browse,so it's faster that way) but you can do it that way directly from the chromium browser on the Pi. Or investiga...
by Tzarls
Fri Jun 29, 2018 5:20 am
Forum: Beginners
Topic: virtual keyboard for touch screen?
Replies: 49
Views: 8022

Re: virtual keyboard for touch screen?

I use Jessie and xvkbd and everything works ok. Now, I remember having the problem you describe (not being able to launch the keyboard again) and found that the version in the repositories apparently had a problem when shutting down. I don't remember exactly how I solved it but I think it had to do ...
by Tzarls
Sat May 26, 2018 6:51 pm
Forum: Beginners
Topic: (Solved) How to shut down a rasp you cant connect to
Replies: 9
Views: 630

Re: How to shut down a rasp you cant connect to

If you have an USB keybiard you can try the following:
1. Plug the keyboard to the Raspberry.
2. Press this combination: control alt f1
3. Write this command: sudo shutdown - h now

If this works, after a few seconds you should see the activity led blinking 10 times, which means your Raspberry is off.
by Tzarls
Wed May 02, 2018 11:06 pm
Forum: The MagPi
Topic: STICKY: Errata
Replies: 54
Views: 55429

Re: STICKY: Errata

Issue 69, page 38: For playing music using omxplayer it says to use the following:

Code: Select all

oxmplayer ~/Music/Anton_Rothschild_-_03_-_Its_Not_Vegas.mp
It should be omxplayer, not oxmplayer.
by Tzarls
Thu Mar 29, 2018 6:35 am
Forum: General discussion
Topic: How expensive does "The Pi Bug" get?
Replies: 32
Views: 2262

Re: How expensive does "The Pi Bug" get?

But what sort of sound should it make? A buzz is no good - we'd really like something that sounds like bagpipes, or maybe church bells. What makes a church bell sound like it does? So now, before we start working out the details of the project, we have to find out what it's going to do. The first t...
by Tzarls
Sun Mar 04, 2018 5:07 am
Forum: Beginners
Topic: Ultrasonic Theremin Problems
Replies: 16
Views: 1341

Re: Ultrasonic Theremin Problems

AFAIK there is a problem with the ultrasonic sensor interface in gpiozero - Basically the sensor won't detect any distance so any project based on distance will not work. I had to develop my own ultrasonic class using Pigpio to make the theremin and other projects work.
by Tzarls
Thu Feb 08, 2018 8:19 pm
Forum: Español
Topic: Raspberry Jam en Lima, Perú
Replies: 0
Views: 294

Raspberry Jam en Lima, Perú

Hola a todos. Les comento que el 3 de marzo estaremos realizando un Raspberry Jam en la ciudad de Lima, Perú, con motivo del aniversario de la Raspberry Pi. La reunión está organizada por la empresa Generación Tec en coordinación con el FabLab de la Universidad ESAN y se llevará cabo en el local de ...
by Tzarls
Mon Jan 29, 2018 6:54 pm
Forum: Camera board
Topic: Camera: Looking for a C++ library that includes encoders
Replies: 2
Views: 595

Re: Camera: Looking for a C++ library that includes encoders

Thanks, I'll have a look at the code you mention.
by Tzarls
Tue Jan 23, 2018 8:46 pm
Forum: Camera board
Topic: Camera: Looking for a C++ library that includes encoders
Replies: 2
Views: 595

Camera: Looking for a C++ library that includes encoders

Hello to all. I need to use the Raspberry Camera (V2) from C++. Not wanting to reinvent the wheel, I searched for some existing library with some kind of interface for controlling the camera and found these 2 examples: https://github.com/cedricve/raspicam http://robotblogging.blogspot.pe/2013/10/an-...
by Tzarls
Tue Nov 28, 2017 12:39 pm
Forum: Beginners
Topic: Script running in IDLE not in Thonny
Replies: 13
Views: 1752

Re: Script running in IDLE not in Thonny

Your script might have been created usong IDLE3 but when you run it from the CLI (as you said you are) then the Python version used depends on what command you are issuing. AFAIK using 'python script.py' will call Python 2. For Python 3 the command would be 'python3 script.py'.
by Tzarls
Thu Nov 16, 2017 6:15 pm
Forum: Python
Topic: Recording Slow Motion video with Official Camera
Replies: 0
Views: 668

Recording Slow Motion video with Official Camera

Hi. Here´s a script to record slow motion video with the official camera v2. I saw a request for this on Twitter so I´m sharing here so anyone can benefit. I´ve added comments so you can adapt this to your own needs. For the script to work you need to install the MP4Box program, which can be done us...
by Tzarls
Sun Oct 29, 2017 12:13 am
Forum: Python
Topic: Audio processing - Have I hit the limit?
Replies: 0
Views: 360

Audio processing - Have I hit the limit?

I have this small script: import pyaudio import time import numpy as np from scipy.signal import butter, lfilter, lfilter_zi def design_filter(lowcut, highcut, fs, order=3): nyq = 0.5*fs low = lowcut/nyq high = highcut/nyq b,a = butter(order, [low,high], btype='band') return b,a def callback(in_data...
by Tzarls
Sun Oct 29, 2017 12:06 am
Forum: Python
Topic: Audio processing with PyAudio - can´t change sample values
Replies: 1
Views: 661

Re: Audio processing with PyAudio - can´t change sample values

Nevermind, I found the answer - it was just a matter of getting the sample formats and numpy arrays right.
by Tzarls
Sun Oct 22, 2017 4:54 am
Forum: Python
Topic: Audio processing with PyAudio - can´t change sample values
Replies: 1
Views: 661

Audio processing with PyAudio - can´t change sample values

Hi. I´m having a hard time trying to do the most basic audio processing using Python with PyAudio. I´ve opened the stream correctly and in my callback function, when I just return the input array I can monitor incomign audio without problems: def callback(in_data, frame_count, time_info, status): re...
by Tzarls
Wed Sep 20, 2017 4:51 pm
Forum: General discussion
Topic: RPI is not intended for serious projects because of its unreliability
Replies: 20
Views: 2554

Re: RPI is not intended for serious projects because of its unreliability

I've got almost 30 RPi, from original b, b+, 2b and 3b, some working 24/7, some used once in a while, some used every day but turned on/off depending on the occasion... They all work fine.... In 5 years i've only got 1 card corrupted to being unusable, and even though I managed to short 5v to ground...
by Tzarls
Sat Aug 26, 2017 2:46 pm
Forum: Automation, sensing and robotics
Topic: Autonomous Indoor Car
Replies: 69
Views: 7497

Re: Autonomous Indoor Car

But then the system would rely on the car starting at an exact known position and heading a known direction. With the NFC tags you can havr the car start anywhere and even if the car doesn't know where it is at the beginning once it finds the first tag it can find on whuch road it is. Second tag (at...

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