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by karlkiste
Thu Oct 31, 2013 6:26 pm
Forum: General discussion
Topic: Can/should the raspi control 100+ LEDs?
Replies: 12
Views: 4881

Re: Can/should the raspi control 100+ LEDs?

If all the LEDs should do the same, you don't need a GPIO pin for each strip. You can just use buffers, which send the same signal from one GPIO pin to all the strips. I'm currently working on a project where one pi will control about 3500 LEDs, each individually, through one pin ;-) But that's anot...
by karlkiste
Thu Oct 31, 2013 5:39 pm
Forum: Deutsch
Topic: Neues Modell?
Replies: 11
Views: 3300

Re: Neues Modell?

Es sieht aus, als kostet ein Cubieboard3 um die 60€. Ich hab letztens 1000 model A Pis verbaut. Mit dem Cubieboard3 hätte ich da im Einkauf was um die 30000€ mehr ausgegeben. Wichtig war nur, Full-HD Video abzuspielen. Mag sein, daß das das Cubieboard3 auch kann, aber wenn ich sonst nichts brauche, ...
by karlkiste
Thu Oct 31, 2013 2:30 pm
Forum: Deutsch
Topic: Neues Modell?
Replies: 11
Views: 3300

Re: Neues Modell?

Ein komplett neues Modell, aber er schliesst Updates des jetztigen Raspi nicht aus. Frühstens Sep 2015 in der schnelllebigen Elektronikwelt? :lol: Ja, es gibt Updates: Der Speicherchip kommt teilweise nicht mehr von Samsung. Nun gut, wenn dir die Maschine nicht Zeitgemäß erscheint, dann kauf was an...
by karlkiste
Thu Oct 31, 2013 11:02 am
Forum: Deutsch
Topic: Neues Modell?
Replies: 11
Views: 3300

Re: Neues Modell?

Eben Upton, Founder, has stated in public that he would expect a NEW board between two and three years from now (Sept 2013). "Eben Upton, der Gründer, hat (im September 2013) öffentlich erklärt, dass er eine neue Platine in zwei bis drei Jahren erwartete." Na, da würde ich doch ganz konkret reinles...
by karlkiste
Wed Oct 30, 2013 9:03 pm
Forum: Troubleshooting
Topic: USB UART - how to make it working? (FT232RL)
Replies: 11
Views: 16786

Re: USB UART - how to make it working?

When I had this effect, there were several tasks running, reading the serial device. So, sometimes my task got the data, sometimes another task "stole" it.
by karlkiste
Wed Oct 30, 2013 8:59 pm
Forum: Other projects
Topic: Extending the status LED's
Replies: 5
Views: 3836

Re: Extending the status LED's

If you've got a means to hold the fibers in place for some time, you can glue them to the LEDs using a tiny drop of transparent epoxy glue. The LEDs are epoxy, so the coupling into the glue is near to perfect. That will give a far better transmission than a dry connection with an air gap.
by karlkiste
Wed Oct 30, 2013 8:52 pm
Forum: Troubleshooting
Topic: USB UART - how to make it working? (FT232RL)
Replies: 11
Views: 16786

Re: USB UART - how to make it working?

And, before the loopback test, run

stty -F /dev/ttyUSB0 -crtscts

to make sure no handshake inhibits data transmission.
by karlkiste
Wed Oct 30, 2013 8:18 pm
Forum: Troubleshooting
Topic: USB UART - how to make it working? (FT232RL)
Replies: 11
Views: 16786

Re: USB UART - how to make it working?

Onira wrote: but when I do

Code: Select all

$ echo "test" > /dev/ttyUSB0
nothing happens
What is it that should be happening? What is the device connected to?
by karlkiste
Wed Oct 30, 2013 10:38 am
Forum: General discussion
Topic: Raspberry pi 1 year warranty, legal in Europe?
Replies: 9
Views: 2875

Re: Raspberry pi 1 year warranty, legal in Europe?

I can tell you about the situation in germany: Warranty is 2 years, but there's a "Reverse onus" kicking in after six months. These six months are often extended by a seller as a bonus to a customer. I think, this is the "one year" Farnell speaks about. What does this mean? If a thing breaks 5 month...
by karlkiste
Wed Oct 30, 2013 6:49 am
Forum: Graphics programming
Topic: EGL - How to use fb1?
Replies: 27
Views: 27349

Re: EGL - How to use fb1?

[...] but the resolution was still higher than 480x272. Can anyone think of a way to force fb0 to be the resolution I need? Just stumbled over it: Of course you can set that resolution: in config.txt disable_overscan=1 framebuffer_width=480 framebuffer_height=272 And, very important, do NOT plug in...
by karlkiste
Wed Oct 30, 2013 5:07 am
Forum: Beginners
Topic: powering my model a
Replies: 14
Views: 1901

Re: powering my model a

Most electronics states 5.5V or 6V as the upper working limit, and no damage is guaranteed up to 7V. And: If you're measuring 5.3V... What does that mean? What's the accuracy of your meter? Some other (more expensive) meter would maybe display 4.983V. Accuracy "5%+1" digit means, that a real Voltage...
by karlkiste
Wed Oct 30, 2013 4:57 am
Forum: Graphics programming
Topic: EGL - How to use fb1?
Replies: 27
Views: 27349

Re: EGL - How to use fb1?

Can I use openGL ES to render without using EGL? Will it still take advantage of the GPU? Is there a way to use the GPU to convert the rendered image from openGL ES to RGB 565 or a more efficient way to do it with the CPU that won't kill my framerate? I'm not very much into this subject, I only und...
by karlkiste
Tue Oct 29, 2013 7:24 pm
Forum: Graphics programming
Topic: EGL - How to use fb1?
Replies: 27
Views: 27349

Re: EGL - How to use fb1?

How do programs like fbi and xserver use only fb1 without having to render to fb0? They just render to fb1. I'm displaying pictures like this: gm convert picture.jpg -scale ${xres}x${yres}! -depth 8 RGB:/dev/fb1 There's no trick to it. To just see anything, you can just cat /dev/urandom >/dev/fb1 Y...
by karlkiste
Tue Oct 29, 2013 6:59 pm
Forum: Beginners
Topic: Command(s) to get just your IP?
Replies: 5
Views: 894

Re: Command(s) to get just your IP?

Look in the file /etc/rc.local of raspbian os.
by karlkiste
Tue Oct 29, 2013 5:16 pm
Forum: Advanced users
Topic: VNC over serial
Replies: 5
Views: 2864

Re: VNC over serial

OK, 1 MBaud may give us around one percent of "normal raspberry-network speed"! Well, let's say "nominal network speed". The pi is about able to send a copy of /dev/zero as udp packets at 100MBit, but this uses up all the CPU. I doubt the pi can send useful data at 100MBit and do anything else in p...
by karlkiste
Tue Oct 29, 2013 2:46 pm
Forum: Python
Topic: Log data to file.
Replies: 2
Views: 682

Re: Log data to file.

I don't know python, I'd do it in bash. cat /dev/ttyAMA0 > fileA & This continuosly writes all data to fileA in a background process. Then, every five minutes, do tail -c $n fileA >fileB This will copy the last $n bytes of fileA to fileB. The bytes will however not be removed from fileA. It is quite...
by karlkiste
Tue Oct 29, 2013 2:01 pm
Forum: Advanced users
Topic: VNC over serial
Replies: 5
Views: 2864

Re: VNC over serial

Serial speed is 115200 baud at maximum, [...] Not always. If you're using something like a MAX232 you're right, the slew rate with those level converters is limited, so 115200 is often a limit. You can however connect one pi to another, and transmit 1MBaud, or even 4MBaud (but the latter surely not...
by karlkiste
Tue Oct 29, 2013 8:09 am
Forum: Deutsch
Topic: [Hife] [Python] Lenge eines GPIO Imput zählen
Replies: 7
Views: 4299

Re: [Hife] [Python] Lenge eines GPIO Imput zählen

Ich hab leider keine Ahnung von python... Die Hardware kann Interrupts auslösen, wenn sich ein GPIO-Pin ändert. Prinzipiell sollte es also möglich sein, bei 700MHz Taktfrequenz (also ca. 1,5ns pro Takt) auf eine Mikrosekunde genau zu messen, auch ohne Echtzeit-Betriebssystem.
by karlkiste
Sun Oct 27, 2013 5:40 am
Forum: Other projects
Topic: Enclosure for sub-zero temperature
Replies: 15
Views: 15582

Re: Enclosure for sub-zero temperature

I'm planning to use pis outdoor as well, so I've tried it. After a night in the freezer at -30°C (-22°F), the (uncased) pi started without a problem, network and USB doing well. Right after booting raspbian, the core temperature reported -20171. After half an hour running under no-load condition, co...
by karlkiste
Sun Oct 27, 2013 4:51 am
Forum: Beginners
Topic: Making of Raspberry Pi with 1GB RAM!
Replies: 12
Views: 15832

Re: Making of Raspberry Pi with 1GB RAM!

for $150 you get a mini-itx dual-core intel atom computer Wondering, what about the forum support and especially libraries of pre-compiled applications for that board [... or] you have a pretty board with not much to run on it ? Well, It's i386 platform, it runs ubuntu, macos, dos, windows, ... The...
by karlkiste
Sat Oct 26, 2013 4:26 pm
Forum: Beginners
Topic: Composite display tweaks
Replies: 15
Views: 9275

Re: Composite display tweaks

I had the setup handy, and can say, my model b with latest raspbian image activates cvbs output while nothing is connected.

If this is not the case with all pis, a 78 ohm resistor can act as an impostor ;-)
by karlkiste
Sat Oct 26, 2013 3:39 pm
Forum: Beginners
Topic: Making of Raspberry Pi with 1GB RAM!
Replies: 12
Views: 15832

Re: Making of Raspberry Pi with 1GB RAM!

hey guys, Actually I searched on the Internet and people are making cheap super computers by joining many raspberry pis together. I also had that idea, but I came to the conclusion that it's inefficient - for $150 you get a mini-itx dual-core intel atom computer with 1.8GHz. You'll need more than f...
by karlkiste
Fri Oct 25, 2013 1:44 pm
Forum: HATs and other add-ons
Topic: Specification for Pi PWM audio??
Replies: 5
Views: 2394

Re: Specification for Pi PWM audio??

Just checked again: It's more like 50MHz. My cheap scope says 49.1. PWM is off when raspbian is booted. When the first sound is played, PWM is switched on, and not switched off afterwards. This is no bug, but a feature: Otherwise there's a really annoying loud click at the start of every sound. Repl...
by karlkiste
Fri Oct 25, 2013 7:10 am
Forum: Beginners
Topic: creating mobile cell network using raspberry pi and huawei 3
Replies: 12
Views: 14122

Re: creating mobile cell network using raspberry pi and huaw

The 3g dongle acts like a cellphone. A cellphone cannot connect to another cellphone, and so it can't connect to the 3g dongle. I feel like it was this you were trying. The machine cellphones connect to are called BTS (base transciever station). You then need a BSC and VLR function, which might be p...
by karlkiste
Fri Oct 25, 2013 5:42 am
Forum: HATs and other add-ons
Topic: Specification for Pi PWM audio??
Replies: 5
Views: 2394

Re: Specification for Pi PWM audio??

What a pity... A year ago, PWM was switched off completely when no sound was played. This lead to a loud click when PWM was switched on. You could have easily detected that... But, to get rid of the click, PWM now stays on, once activated. Then, when I had a look with my cheap scope, I saw something...

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