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by DougieLawson
Fri Oct 18, 2013 10:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connecting an unknown temperature sensor to the Pi
Replies: 17
Views: 3763

Re: Connecting an unknown temperature sensor to the Pi

I took some pictures for you guys to see: http://i1135.photobucket.com/albums/m638/BazsoDombiAndras/Components/TempSensor_Front_01_zps1a1eef67.jpg http://i1135.photobucket.com/albums/m638/BazsoDombiAndras/Components/TempSensor_Back_01_zpse9ceaa8c.jpg While processing the images, I noticed that on t...
by DougieLawson
Fri Oct 18, 2013 5:54 pm
Forum: Troubleshooting
Topic: SSH refused from external network, works on internal network
Replies: 9
Views: 7362

Re: SSH refused from external network, works on internal net

Just to show what I was saying, attached is the port forwarding section of my router Have you given your RPi a fixed IP address and used that in the router? You can't rely on DHCP always handing out the same address when the lease expires. Have you used dyndns or no-ip or http://freedns.org to give...
by DougieLawson
Fri Oct 18, 2013 5:52 pm
Forum: Troubleshooting
Topic: SSH refused from external network, works on internal network
Replies: 9
Views: 7362

Re: SSH refused from external network, works on internal net

I don't expose my RPi to the public internet (because my Ubuntu server is doing that and I can use it as a gateway to my RPi). On Ubuntu I got UFW installed as part of the basic software. It's definitely the easiest way to fiddle with the kernel ip tables. sudo apt-get update sudo-apt-get install uf...
by DougieLawson
Mon Oct 14, 2013 8:43 am
Forum: Troubleshooting
Topic: Network is not reachable
Replies: 6
Views: 1135

Re: Network is not reachable

Are you using a wired connection (eth0) or a USB WiFi dongle (wlan0)? If using a WiFi dongle try pulling it out of the USB socket and re-inserting it (my Edimax dongle winks a blue LED when it's working). Have you configured your WiFi SSID and password? If using a wired connection do you get the gre...
by DougieLawson
Mon Oct 14, 2013 8:14 am
Forum: Beginners
Topic: File copying
Replies: 5
Views: 32005

Re: File copying

If a file is in the wrong place it's probably better to create a symbolic link to the original rather than copying. That way when you install a package that replaces the original file then the alternative destination gets the new copy rather than the stale copy. Read the syntax and options with a `m...
by DougieLawson
Mon Oct 14, 2013 7:56 am
Forum: C/C++
Topic: Which language to use?
Replies: 32
Views: 73618

Re: Which language to use?

The choice of language depends on a number of criteria. Speed Ease of programming Ease of maintenance Processor and operating system Interpreted or compiled or compiled to interpreted byte code Procedural or object oriented For speed of running but slow development I'd choose assembler every time (I...
by DougieLawson
Sun Oct 13, 2013 11:23 am
Forum: Teaching and learning resources
Topic: Boy Scout Programmin Merit Badge
Replies: 7
Views: 4140

Re: Boy Scout Programmin Merit Badge

I was looking for some docs on the Python programming language (for a friend with a RPi, yesterday). Hopefully these two should be a good starting point for the BSA merit badge. This is the University of Cambridge education material http://downloads.raspberrypi.org/Raspberry_Pi_Education_Manual.pdf ...
by DougieLawson
Sun Oct 13, 2013 11:09 am
Forum: Troubleshooting
Topic: mmcblk0: retrying using single block read
Replies: 2
Views: 2116

Re: mmcblk0: retrying using single block read

I think your SD Card is less than healthy. It's not broken because you can reboot. Have you updated your RPi to the latest kernel image? What does `uname -a` show? root@pi ~ # uname -a Linux pi 3.6.11+ #538 PREEMPT Fri Aug 30 20:42:08 BST 2013 armv6l GNU/Linux root@pi ~ # If you're on an earlier ker...
by DougieLawson
Sun Oct 13, 2013 10:58 am
Forum: Troubleshooting
Topic: Emulation Station
Replies: 1
Views: 470

Re: Emulation Station

Device (179,2) is the second partition /dev/mmcblk0p2 on your SD Card. The kernel is looking for a root filesystem on that partition (because that's what you've got in /boot/cmdline.txt). This is what I've got on my Raspbian SD Card dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ex...
by DougieLawson
Tue Oct 08, 2013 7:57 am
Forum: Beginners
Topic: SD Corrupt
Replies: 6
Views: 1375

Re: SD Corrupt

Oakham wrote:One of several previous postings relating to "sd card issues"

http://www.raspberrypi.org/phpBB3/viewt ... rd+corrupt
I don't think that helps since that thread has been dormant since September and doesn't have any firm conclusions.
by DougieLawson
Tue Oct 08, 2013 7:45 am
Forum: General discussion
Topic: changes on /etc/resolve.conf not getting saved upon reboot
Replies: 10
Views: 53553

Re: changes on /etc/resolve.conf not getting saved upon rebo

That should work.

The dns-nameservers statement relates to the iface stanza that comes before it. That means you can have different specifications depending on which interface is connected.
by DougieLawson
Tue Oct 08, 2013 7:43 am
Forum: Troubleshooting
Topic: Not booting
Replies: 4
Views: 895

Re: Not booting

Download this ZIP and extract it on your Windows machine http://downloads.raspberrypi.org/NOOBS_latest Download this SD formatting tool https://www.sdcard.org/downloads/formatter_4/eula_windows/SDFormatterv4.zip Unzip that file and install the program on Windows Watch this video (seven minutes long)...
by DougieLawson
Sat Oct 05, 2013 9:16 am
Forum: General discussion
Topic: RaspBMC SD Corruption
Replies: 4
Views: 1468

Re: RaspBMC SD Corruption

If you don't shutdown normally then you could corrupt the filesystem. To fix it you need to use `fsck` for ext4 on a Linux system. I'm surprised that XBMC isn't configured to do that automatically. If there isn't a forced fsck defined in /etc/fstab then you'll need to boot your RPi from another SD c...
by DougieLawson
Sat Oct 05, 2013 8:59 am
Forum: General discussion
Topic: changes on /etc/resolve.conf not getting saved upon reboot
Replies: 10
Views: 53553

Re: changes on /etc/resolve.conf not getting saved upon rebo

You can't just use nano (or vi) on /etc/resolv.conf. That will be overwritten every time you disconnect, reconnect, shutdown or reboot. Resolv.conf is updated by the ifup/ifdown process based on what's in your /etc/network/interfaces definitions. Edit /etc/network/interfaces and add your preferred n...
by DougieLawson
Sat Oct 05, 2013 8:51 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Topview A1981Wx monitor
Replies: 2
Views: 967

Re: Topview A1981Wx monitor

The yellow socket on the RPi is composite video (in my case it's a PAL signal). Use a lead with two RCA plugs to hook it up to the composite input on your monitor. You may need to update /boot/config.txt framebuffer_width=www framebuffer_height=hhh to set the width and height to get the picture to f...
by DougieLawson
Sat Oct 05, 2013 8:41 am
Forum: Beginners
Topic: sd card
Replies: 9
Views: 1059

Re: sd card

Hai everyone, maybe its a hardware issue but my laptop wont write to the sd card,using open suse 12,1 dd command dd bs=1M if=/home/harrydevries/Downloads/NOOBS_v1_2_1 of=/dev/sdb1 what did i forget? appreciate your tips and tricks kind regard Harry.. You don't want to write NOOBS to partition 1 (/d...
by DougieLawson
Wed Oct 02, 2013 7:53 pm
Forum: Troubleshooting
Topic: Edimax WiFi Adapter - Can scan wifi networks but no internet
Replies: 7
Views: 2209

Re: Edimax WiFi Adapter - Can scan wifi networks but no inte

I want my RPi to have a fixed IP address and my home network is 10.1.1.0/24 (netmask 255.255.255.0). Your network is probably 192.168.0.1/24 (so you'll need to change things as appropriate). I set it up like this: /etc/network/interfaces auto lo auto wlan0 iface lo inet loopback iface eth0 inet dhcp...
by DougieLawson
Wed Oct 02, 2013 12:04 pm
Forum: Beginners
Topic: Adding date time stamp to a jpg picture
Replies: 16
Views: 35302

Re: Adding date time stamp to a jpg picture

Update your program running raspistill to have the -exif flag. Install ImageMagick with sudo apt-get install imagemagick Try this shell script: #!/bin/bash for file in *.jpg ; do convert "$file" -font arial.ttf \ -pointsize 72 -fill white -annotate +100+100 \ %[exif:DateTimeOriginal] "new-${file}" d...
by DougieLawson
Wed Oct 02, 2013 11:47 am
Forum: Beginners
Topic: clarification of capability before ordering
Replies: 3
Views: 839

Re: clarification of capability before ordering

does the motor control relay board have addressing to be able to differentiate between each other if a number are installed in series at the same time on a backplane? If you use a board with a MCP23017 it's addressed using I2C and you can daisy chain up to eight of them. That would give 128 uniquel...
by DougieLawson
Mon Sep 16, 2013 11:52 pm
Forum: Networking and servers
Topic: LDAP Setup
Replies: 1
Views: 1303

Re: LDAP Setup

If you don't pass any special parms then `sudo` will run the command with root (UID 0) authority. You can demonstrate that by running `sudo whoami`.

Best of luck with LDAP, I found it horribly complex to set-up as the password/users/groups data store for my samba system.
by DougieLawson
Mon Sep 16, 2013 11:29 pm
Forum: Networking and servers
Topic: [Potential Soln] PHP deleting files on network share
Replies: 2
Views: 954

Re: [Potential Soln] PHP deleting files on network share

I think this is a very bad idea. My webserver and sshd gets requests from all over the world that are constantly trying to breach my security. So I'm doing lots of stuff to prevent PHP from accessing anything important or anything that isn't transient or carefully contained in a MySQL database. I'm ...
by DougieLawson
Mon Sep 16, 2013 11:08 pm
Forum: Troubleshooting
Topic: Connecting to WiFi
Replies: 9
Views: 1770

Re: Connecting to WiFi

I'm a brand new user. I have a Pi with Raspbian and I installed an RPi edimax EW-7811 wifi dongle. I ran the wifi config program. The pi sees the network, but I can't connect to it. What am I doing wrong? I'll assume that you can access your WiFi network from a smartphone, Windows laptop or Mac and...
by DougieLawson
Mon Aug 26, 2013 3:12 pm
Forum: Beginners
Topic: how can I take snapshoot from security cam every few second?
Replies: 10
Views: 1756

Re: how can I take snapshoot from security cam every few sec

There's an article in Issue 15 of MagPi that covers this topic.
http://issuu.com/themagpi/docs/issue15final and go to page 11
Or download the PDF from http://www.themagpi.com/en/issue/15/pdf/

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