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by rpdom
Mon Mar 04, 2013 4:06 pm
Forum: Bare metal, Assembly language
Topic: Baking Pi ok05 timer - must use r2/r3?
Replies: 2
Views: 737

Re: Baking Pi ok05 timer - must use r2/r3?

In the example code, r4 and r5 are used for the pattern and seq values. If you are using the same registers in wait (without preserving the values), then you will overwrite them and mess up the flash sequence.
by rpdom
Mon Mar 04, 2013 7:13 am
Forum: General discussion
Topic: Bash script works but strange message
Replies: 58
Views: 7384

Re: Bash script works but strange message

Just to add a bit of confusion into the mix ;-)

If all you want to do is check if x and y both = 0 or not, you can use:

Code: Select all

if [ "$x$y" = "00" ]
then
  # do stuff here
else
  # do other stuff here
fi
by rpdom
Mon Mar 04, 2013 7:03 am
Forum: Troubleshooting
Topic: Is My Pi Dead? (doesn't boot - red light only)
Replies: 18
Views: 11194

Re: Is My Pi Dead? (doesn't boot - red light only)

Yes, you pull out the power to turn it off... but you must at least try to shut it down properly first. Same as you would a PC.
by rpdom
Mon Mar 04, 2013 5:18 am
Forum: Other projects
Topic: Wrong colors on TV Headend (Composite Video Out)
Replies: 65
Views: 10624

Re: Wrong colors on TV Headend (Composite Video Out)

I've only just got around to checking this, even though I ran the rpi-update a few days ago.

I can confirm that it didn't work on the previous update, but looks good now. I have a Raspberry and not a Blueberry again :-)

I hope this has fixed it for the OP and others too.

Thanks Dom!
by rpdom
Mon Mar 04, 2013 5:15 am
Forum: Other projects
Topic: Raspberry pi and 12/24V doorbell
Replies: 5
Views: 2605

Re: Raspberry pi and 12/24V doorbell

The 4N33 should be fine. For the resistors, lets assume you want 10mA at 2V (makes the calculations easier). If the doorbell is 12V, you need to drop 10V across the resistor. Ohms Law says the Voltage = Current x Resistance (V=IR), so R = V / I R = 10V / 0.010A (10mA). Therefore R = 1000 Ohms, or 1K...
by rpdom
Mon Mar 04, 2013 4:51 am
Forum: Beginners
Topic: 'authentication error'
Replies: 2
Views: 598

Re: 'authentication error'

If you haven't changed anything in your setup yet, I'd say that that you have a bad image file somehow.

If you have changed things, I'd guess that there is an error in /etc/inittab
by rpdom
Sun Mar 03, 2013 1:49 pm
Forum: Troubleshooting
Topic: Installing Screen failed
Replies: 4
Views: 1028

Re: Installing Screen failed

Your package list/index is out of date. That version of screen has been replaced with a new one, so you won't be able to find the file. General rule of thumb with Raspbian - always run apt-get update before running apt-get install or apt-get upgrade. apt-get update will fetch the latest index files ...
by rpdom
Sun Mar 03, 2013 1:41 pm
Forum: Other projects
Topic: monitor psu to power portable pi?
Replies: 2
Views: 645

Re: monitor psu to power portable pi?

Yes, you have bought the right thing. That UBEC will happily drop 12V to 5V and power your Pi :) If the display takes 6-8W at 12V direct from your power supply, that will be about 500-670mA, as you worked out. As the regulator is switching, rather than linear, it will only need about 400mA at 12V to...
by rpdom
Sat Mar 02, 2013 7:51 am
Forum: Bare metal, Assembly language
Topic: Baking Pi OK01 clarification
Replies: 3
Views: 1113

Re: Baking Pi OK01 clarification

(Let's see if I can get this right..) The CPU by default handles 32 bits at a time, that is 4 x 8 bits. These must be word aligned - ie end in 0, 4, 8 or c. There are versions of some instructions that handle 8 or 16 bits at a time, but they actually still use 32 bit data, just discarding or preserv...
by rpdom
Fri Mar 01, 2013 5:28 pm
Forum: General discussion
Topic: Composite > VGA converter for Rasberry Pi
Replies: 6
Views: 2461

Re: Composite > VGA converter for Rasberry Pi

I use one of these http://www.ebay.co.uk/itm/CCTV-DVD-DVR-TV-RCA-AV-S-Video-Composite-Video-input-to-VGA-PC-Converter-Adapter-/220898958318?pt=UK_Computing_Sound_Vision_Video_Cables_Adapters&hash=item336e9a9bee It seems to work ok and I have my DVD player hooked up to the S-Video input too, so I can...
by rpdom
Fri Mar 01, 2013 5:16 pm
Forum: Beginners
Topic: Can't install Transmission-Daemon
Replies: 4
Views: 4259

Re: Can't install Transmission-Daemon

apt-get update - updates the list of what software is available from the servers. This is the most important one. apt-get upgrade - downloads and installs any updated software - as long as that doesn't require installing extra software or deleting already installed software. apt-get dist-upgrade - L...
by rpdom
Fri Mar 01, 2013 2:48 pm
Forum: General discussion
Topic: few questions
Replies: 6
Views: 797

Re: few questions

Starting the X server puts quite a drain on the PSU. Have you tried measuring the TP1 - TP2 voltage when you do that? Some PSUs claim to be rated 1A, but can't always cope (I have a no-name cheap one rated 1A that drops to about 3V when I try and take more than 0.2A from it). The other thing is the ...
by rpdom
Fri Mar 01, 2013 2:38 pm
Forum: General discussion
Topic: using pi's on board usb to recieve data from pc and store in
Replies: 3
Views: 633

Re: using pi's on board usb to recieve data from pc and stor

Simple answer. No, it's not possible. The PC is a Master USB device. The Pi is a Master USB device. You can only connect slaves to masters. Complicated answer: There are some cables that will allow a Master to Master connection via a bit of electronic trickery in the middle, but even that won't do w...
by rpdom
Fri Mar 01, 2013 1:28 pm
Forum: General discussion
Topic: Raspbian on the HDD for booting (SOLVED)
Replies: 8
Views: 5081

Re: Raspbian on the HDD for booting

When talking about the image, do you mean you downloaded a fresh image file? If so, you should extract it to /dev/sdb, not /dev/sdb1 (Caution: This will overwrite anything on the disk!). Then disconnect the drive and plug it in again and you will see /dev/sdb1 (FAT) and /dev/sdb2 (ext4) - the same a...
by rpdom
Fri Mar 01, 2013 7:05 am
Forum: General discussion
Topic: Beep on Power On
Replies: 4
Views: 1811

Re: Beep on Power On

This could be done a number of ways with simple circuits conneted to the GPIO power pins. For example: 1. A capacitor that charges slowly from the 5v line, driving a transistor that runs another pair of transistors as an oscilator to produce the sound, stopping one the capacitor is charged. 2. A pai...
by rpdom
Fri Mar 01, 2013 6:55 am
Forum: Troubleshooting
Topic: Using serial port as non root
Replies: 1
Views: 511

Re: Using serial port as non root

Normally, serial ports have a group of "dialout" and adding your user to that group would be sufficient. I'm not sure that changing the permissions or ownership of the port is a good idea.
by rpdom
Fri Mar 01, 2013 6:41 am
Forum: Beginners
Topic: Help Gettin ssh working
Replies: 8
Views: 1066

Re: Help Gettin ssh working

You do not need a crossover cable to connect anything to the pi (assuming you're using the on-board ethernet). It has auto-sense and will handle the crossover automatcally if needed. Any standard network cable will do.
by rpdom
Fri Mar 01, 2013 6:35 am
Forum: General discussion
Topic: Bash text colours - need monochrome - help !
Replies: 4
Views: 2304

Re: Bash text colours - need monochrome - help !

The "ls" command has been aliased to use "ls --color=auto" which shows different types of files in different colours. Some people like this, it seems. To disable it for your current session, use "unalias ls". To disable it permently for that user, edit .bashrc and comment out the line " alias ls='ls...
by rpdom
Thu Feb 28, 2013 12:21 pm
Forum: Beginners
Topic: Please help compiling an IM
Replies: 5
Views: 857

Re: Please help compiling an IM

don't just download the default wheezy package as you'll end up with amd64 or i386 not armv6. try: http://packages.debian.org/wheezy/armhf/pidgin/download I wouldn't recommend this unless you want to break your system. The standard Debian armhf does not support armv6. It is armv7 and above only. St...
by rpdom
Thu Feb 28, 2013 11:08 am
Forum: Beginners
Topic: Please help compiling an IM
Replies: 5
Views: 857

Re: Please help compiling an IM

Seeing as you mention it, I'm going to assume you are using Raspbian. Have you looked to see if ekg2 is already built and available for Raspbian? clue: apt-cache show ekg2 If it is, then you don't need to bother with messing around with compiling it yourself (unless you want the practice), just inst...
by rpdom
Thu Feb 28, 2013 10:46 am
Forum: Troubleshooting
Topic: Getting IP from int. network, unable to connect to internet
Replies: 4
Views: 741

Re: Getting IP from int. network, unable to connect to inter

Hmm, if the IP comes from the Mac Mini, then that should be providing the dns server addresses too. I wonder if there is a settng for that?
by rpdom
Wed Feb 27, 2013 3:54 pm
Forum: Raspbian
Topic: uuencode, broken and intermittent segfault??
Replies: 5
Views: 2069

Re: uuencode, broken and intermittent segfault??

I'd do

sudo apt-get --reinstall install sharutils

to reinstall the package
by rpdom
Wed Feb 27, 2013 6:33 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Pi = DCC for model railways?
Replies: 34
Views: 24498

Re: Pi = DCC for model railways?

I believe a few people have been working on this and may have been some success.

Searching the forums for "model railway dcc" seems to get a number of hits.
by rpdom
Wed Feb 27, 2013 6:12 am
Forum: Troubleshooting
Topic: Getting IP from int. network, unable to connect to internet
Replies: 4
Views: 741

Re: Getting IP from int. network, unable to connect to inter

Are you using fixed IP addresses on your Pi, or is it getting an address from a DHCP server (in the router or something). If it gets it's address via DHCP, it should also be given the addresses of the DNS server(s) at the same time. If you are using a fixed or static address in /etc/interfaces, then...
by rpdom
Tue Feb 26, 2013 6:32 pm
Forum: Beginners
Topic: Download via Console
Replies: 5
Views: 20233

Re: Download via Console

wget is the command to download files from the internet in Linux (it is installed by default in Raspbian).

Example:

wget http://download.udk.com/UDKInstall-2013-02-BETA2.exe

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