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by rpdom
Wed Aug 06, 2014 6:26 am
Forum: Other projects
Topic: Case Fan - will this work (link in post)?
Replies: 5
Views: 2667

Re: Case Fan - will this work (link in post)?

A 12v brushless fan should work with 5v power supply I have a mini fan for Pi doing just that. At 5v the fan spins slower than 12v and produces less air flow but should be sufficient to cool the board. I'm not sure what the 3rd wire in the connector does but I believe you'll only need yellow and bl...
by rpdom
Wed Aug 06, 2014 6:23 am
Forum: Troubleshooting
Topic: Inteface problem
Replies: 4
Views: 623

Re: Inteface problem

Have you looked at the Sticky Topic about Not Booting/No Video at the top of this forum yet?

http://www.raspberrypi.org/forums/viewt ... 28&t=58151
by rpdom
Wed Aug 06, 2014 5:59 am
Forum: Off topic discussion
Topic: 100 RPi supercomputer w/ 20 GPU boards, appreciate for help
Replies: 128
Views: 26618

Re: 100 RPi supercomputer w/ 20 GPU boards, appreciate for h

As per my calculations so far... I need about 20k dollars for this observatory.... Not if it includes 100 RPis. Those along would be $35K (assuming Model B). Even though I was very much the science and math geek in high school,... Not so much of a math geek if $35 x 100 = $35000 ;) Try $3.5K :)
by rpdom
Tue Aug 05, 2014 4:30 pm
Forum: Troubleshooting
Topic: Raspberry Pi webserver dropping
Replies: 6
Views: 982

Re: Raspberry Pi webserver dropping

There's a good excuse for a trip to Costa Coffee or Starbucks or MaccyD's burger shop when you want to test connectivity from the public internet. It's worth the price of their expensive and undrinkable stuff labeled as coffee to attack your system from outside. I prefer my local Library where the ...
by rpdom
Tue Aug 05, 2014 8:09 am
Forum: Beginners
Topic: Software for Raspberry
Replies: 2
Views: 525

Re: Software for Raspberry

The same software will work on both machines. The only other difference between the A and B is that the B has two USB sockets (via an onboard hub) and Ethernet. The B uses more power. Also, buy a B+ if you can instead of a B. It uses less power, has four USB sockets, more GPIO pins and a whole lot o...
by rpdom
Tue Aug 05, 2014 6:18 am
Forum: General discussion
Topic: USB Device Security
Replies: 4
Views: 717

Re: USB Device Security

Richard-TX wrote:Seems that USB devices have a rather large gaping (sucking chest wound?) security hole in them.

http://www.zdnet.com/badusb-big-bad-usb ... 000032211/
Like this sort of thing http://www.raspberrypi.org/forums/viewt ... 0&p=282270 ?
by rpdom
Tue Aug 05, 2014 6:14 am
Forum: Troubleshooting
Topic: B+ USB overcurrent detect?
Replies: 2
Views: 1490

Re: B+ USB overcurrent detect?

The red Power LED goes out if there is a brownout (it triggers at something like 4.6V). You can also detect that in software by monitoring GPIO 35.
by rpdom
Tue Aug 05, 2014 5:57 am
Forum: Beginners
Topic: how to print the reading from a hall effect sensor?
Replies: 8
Views: 1965

Re: how to print the reading from a hall effect sensor?

the flow sensor i use is g1/2 water flow sensor http://www.seeedstudio.com/wiki/G1/2_Water_Flow_sensor That should work, with a voltage divider, as others have said. Whatever you do, don't follow the Arduino breadboard example picture. It's not right for the Pi, obviously, but it's also wrong for a...
by rpdom
Mon Aug 04, 2014 7:01 pm
Forum: Troubleshooting
Topic: vga monitor turns blue and not displaying any
Replies: 21
Views: 2894

Re: vga monitor turns blue and not displaying any

I have six buttons. AV/SV which switches between Composite and S-Video inputs. PC which enables/disables VGA input PIP which doesn't seem to do anything other than make the screen flicker (I'm sure it does more than that, but I'd need to read the instructions) MODE which changes the output VGA resol...
by rpdom
Mon Aug 04, 2014 6:55 pm
Forum: General discussion
Topic: Faulty USB ports on pi B+ (SOLVED - please update firmware!)
Replies: 34
Views: 5745

Re: Faulty USB ports on pi B+

Going back to the original problem, I did a trial - I burnt a September 2013 Raspdian image onto a micro SD card. The B+ wouldn't entertain it at all, power light but nothing else whatever, presumably it was too old to recognise the memory in the B+. Stuck it in an adaptor and shoved it in my B ori...
by rpdom
Mon Aug 04, 2014 5:40 pm
Forum: Troubleshooting
Topic: vga monitor turns blue and not displaying any
Replies: 21
Views: 2894

Re: vga monitor turns blue and not displaying any

Yep, that looks very much like the one I use.

It displays a blue screen if the selected input doesn't have a signal.

Either your Pi isn't putting out a signal on Composite, you haven't selected Composite Video input using the buttons on the converter, or it is broken.
by rpdom
Mon Aug 04, 2014 4:22 pm
Forum: Troubleshooting
Topic: vga monitor turns blue and not displaying any
Replies: 21
Views: 2894

Re: vga monitor turns blue and not displaying any

From what the OP is saying, they are using a Composite (RCA) to VGA active converter, as Ido with one of my Pi. On mine, when there is no video input, or the wrong video input is selected (It supports composite/RCA, S-Video and VGA inputs), it will just give a blue screen on the VGA output, which se...
by rpdom
Mon Aug 04, 2014 3:30 pm
Forum: General discussion
Topic: Using MANY GPIO's at the same time
Replies: 9
Views: 1659

Re: Using MANY GPIO's at the same time

So, one Pi, 40+ DS18B20 sensors connected to GPIO 4. Depends how quickly you want the changes in temperature to register and the accuracy you need.
by rpdom
Mon Aug 04, 2014 3:22 pm
Forum: Advanced users
Topic: ACT led GPIO # on RPi B+
Replies: 8
Views: 6223

Re: ACT led GPIO # on RPi B+

It is GPIO 47, and the action has been reversed. On the B you set the GPIO to 0 to turn on the LED and 1 to turn it off. On the B+ you set it to 1 to turn on and 0 to turn off.

You can also control the PWR LED on GPIO 35.
by rpdom
Mon Aug 04, 2014 1:42 pm
Forum: Troubleshooting
Topic: error extracting tar ball
Replies: 3
Views: 469

Re: error extracting tar ball

It looks like a bad card to me.
by rpdom
Mon Aug 04, 2014 1:13 pm
Forum: Troubleshooting
Topic: Trouble with video over 3.5mm jack with B+
Replies: 69
Views: 21933

Re: Trouble with video over 3.5mm jack with B+

I wonder if the RPi team could make a config.txt option that would swap the L/R audio channels to match the plugs? Otherwise there might be a way of doing it in the kernel audio driver. I'm assuming that there's no way that the video and audio pins could be jiggled around to match the other cables a...
by rpdom
Mon Aug 04, 2014 1:09 pm
Forum: Troubleshooting
Topic: Raspbian halt after ssh reboot
Replies: 6
Views: 1039

Re: Raspbian halt after ssh reboot

Hi, which command(s) did you use to start the reboot?

Did you capture any of the output from the shutdown/reboot messages?

It is difficult to debug this sort of problem with so little to go on :(

I have had no problems with reboots failing on my B+ so far.
by rpdom
Mon Aug 04, 2014 11:13 am
Forum: Advanced users
Topic: [solved] SUDO ?
Replies: 9
Views: 1938

Re: SUDO ?

Does the script in /etc/init.d have a PATH statement in it that includes /sbin? Some of the others do. For example /etc/init.d/ntp: #!/bin/sh ### BEGIN INIT INFO # Provides: ntp # Required-Start: $network $remote_fs $syslog # Required-Stop: $network $remote_fs $syslog # Default-Start: 2 3 4 5 # Defa...
by rpdom
Mon Aug 04, 2014 11:06 am
Forum: Beginners
Topic: how to print the reading from a hall effect sensor?
Replies: 8
Views: 1965

Re: how to print the reading from a hall effect sensor?

P.S. confusingly you use "water flow sensor" and "hall effect sensor", as if they are interchangeable, their are not, a hals effect sensor senses a magnetic field. Ar you using a hall effect sensor to detect a magnet on a float? The water flow sensor could be a spinning magnet in a pipe where the r...
by rpdom
Mon Aug 04, 2014 9:54 am
Forum: Automation, sensing and robotics
Topic: Reed switches
Replies: 8
Views: 2530

Re: Reed switches

I think it would depend on how it is triggered. If, for example, it was in a door frame next to a magnet and the alarm is triggered when the magnet moves away from the switch, it would need to be Normally Open as the magnet will hold it closed. If it gets triggered by a magnet coming close to it, it...
by rpdom
Mon Aug 04, 2014 9:39 am
Forum: Bare metal, Assembly language
Topic: FrameBufferInfo alignment (Baking Pi)
Replies: 15
Views: 2488

Re: FrameBufferInfo alignment (Baking Pi)

1) .align 4 should be sufficient. That makes sure the data is aligned on a 16-byte boundary. To quote one of the documents The buffer itself is 16-byte aligned as only the upper 28 bits of the address can be passed via the mailbox. The low 4 bits in the mailbox are used for the channel number. 2) Ye...
by rpdom
Mon Aug 04, 2014 5:11 am
Forum: Troubleshooting
Topic: apt-get upgrade destroyed dpkg
Replies: 11
Views: 2673

Re: apt-get upgrade destroyed dpkg

You seem to have some odd versions there. Did you install anything manually with dpkg at any point?

Just to check, could you post the output of

Code: Select all

apt-cache policy gcc libc6-dev cpp gcc-4.6
(sudo not required)
by rpdom
Mon Aug 04, 2014 4:43 am
Forum: General discussion
Topic: Faulty USB ports on pi B+ (SOLVED - please update firmware!)
Replies: 34
Views: 5745

Re: Faulty USB ports on pi B+

As it is code that runs on the GPU hardware layer beneath the CPU and OS, it could be termed Underware :lol:
by rpdom
Sun Aug 03, 2014 6:51 pm
Forum: General discussion
Topic: ls type listings in colo(u)r?
Replies: 6
Views: 6431

Re: ls type listings in colo(u)r?

To see how the colors are/can be set, see the dircolors command (man dircolors). That will tell you that "dircolors --print-database" will show how the colours are usually defined. rpdom@raspi1:~$ dircolors --print-database # Configuration file for dircolors, a utility to help you set the # LS_COLOR...
by rpdom
Sun Aug 03, 2014 4:48 pm
Forum: General discussion
Topic: SSH server with two ports.
Replies: 12
Views: 4083

Re: SSH server with two ports.

Alex, I was sure that the "super"hub had the option to redirect to different ports, but as I said above I have checked on mine and it doesn't do that now. All it has is the option to direct an incoming port (or range of ports) to a particular internal IP address, but not a different port. I suspect ...

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