Archive for month: July, 2012

Using a PS3 EyeToy with the Raspberry Pi

25 Jul
July 25, 2012

Having heard about the new camera driver built into the kernel of the new Raspbian OS image, I decided to have a play, using my PS3 EyeToy camera. The steps below are based on this forum thread, with some changes to reflect my own experience. The Raspberry Pi supports a number of cameras, not just the EyeToy, so if you have a spare one lying around, give it a go.

  1. Install the ‘motion’package:sudo apt-get install motion

    This should automatically install the required ‘ffmpeg’ package – if not you can just do sudo apt-get install ffmpeg.
  2. Edit the config file:

    sudo nano/etc/motion/motion.conf

    To enable daemon mode (so you can run the software in the background without it tying up your terminal):

    daemon on

    To increase the resolution to the maximum supported by the EyeToy, change the following lines:width 640
    height 480

    If you want the stream to be viewable from other computers on the network (rather than just the Pi itself):

    webcam_localhost off

    If you want to change the port on which the stream is served (default 8080) – replace 1234 with the desired port number:

    webcam_port 1234

    By default, the camera will only start capturing images (and video) if it detects motion. If you want to take regular snapshots whether motion is detected or not, you can change the following line (the value is in seconds):

    snapshot_interval 60

    (Press Ctrl+X, Y then Enter to save changes and quit the nano editor)

    There are loads of other things you can do such as enable a basic remote control interface, tweak the JPEG quality, set up regular snapshots (by default, snapshots are taken only when motion is detected), customise the text which is overlaid onto the image and change the location to which images are saved (by default these go into /tmp/motion which is deleted whenever the Pi is rebooted). Just have a browse through the config file which is fairly well-commented and self-explanatory.

  3. Now plug the EyeToy into a USB port on your Pi. The two LEDs (one red, one blue) should illuminate. These are not necessary for webcam use so you may want to cover them with black electrical tape or similar.
  4. Start up ‘motion’ in interactive mode (this is a text-mode app which you can run from the terminal, you don’t need to be in the ‘startx’ GUI:sudo motion -n

    (Without the sudo, I get permission errors which I haven’t yet figured out how to resolve).
  5. Browse to the IP address of your Raspberry Pi on the port you configured earlier (or 8080 if you didn’t change it) in a Web browser. Firefox works fine, but at the time of writing the current stable version of Chrome seems to have a bug with motion JPEG streams, and only shows the first frame. You can work around this by embedding the stream into a simple HTML page, which works fine in Chrome:<img src="http://ip.address.here:1234" />

    Alternatively you can open the stream in VLC.¬†You can also browse to the feed on the Raspberry Pi itself, but you will have to install Chrome or Firefox on it as the built-in Midori browser doesn’t support MJPEG streams.

  6. Once you are satisfied, press Ctrl+C in the terminal to stop the server. You can then start it up in daemon mode:sudo motion
  7. If you need to stop the daemon, get its process ID:cat /var/run/motion/motion.pid

    And kill it (replace 12345 with the ID from the above file):sudo kill 12345

    If you want to automate this:

    sudo nano /usr/bin/killmotion

    And type in or paste the following lines:

    #!/bin/bash
    sudo kill `cat /var/run/motion/motion.pid`

    (Again press Ctrl+X, Y then Enter to save changes and quit)

    Finally make the script executable:
    sudo chmod a+x /usr/bin/killmotion

    And whenever you need to stop the motion daemon, just type:
    killmotion

And there you have it – a simple baby monitor, security camera or basis for time-lapse photography!

The files can build up quickly though, particularly if you enable regular snapshots, so make sure you have plenty of space on the SD card you are using.

Unfortunately, like the original poster, I noticed that occasional frames had a strange form of corruption (example), which unfortunately the camera detects as motion (although you can tweak the config file to only trigger after a number of consecutive frames of motion). I suspect this may be due to the Raspberry Pi not providing quite enough power to run the camera stably. A powered USB hub may solve the problem, or more drastically, desoldering the two LEDs. Reducing the resolution back down to 352×288 apparently fixes the problem, but obviously means lower image fidelity.

If you don’t already have an EyeToy or spare webcam, it’s probably best to wait for the official Raspberry Pi camera module. It will plug into a dedicated connector on the board so you’re not hogging a USB port, and will obviously be more stable. The pre-release version uses a 14-megapixel sensor, but it’s likely that a lower resolution sensor will be used in the final release to keep the costs down. A good-quality 720p (just under 1 megapixel) sensor would be nice, 1080p (just over 3 megapixels) even better.

How to set up a web interface for a Heatmiser wi-fi thermostat using a Raspberry Pi

07 Jul
July 7, 2012

My earlier post on the Heatmiser PRT-TS wi-fi thermostat proved very popular and is the most commented article on this blog. When commenter Rich mentioned the heatmiser-wifi project, a set of Perl scripts that can be installed on a PC or Raspberry Pi to provide a full-featured web interface for the Heatmiser, I just had to give it a go.

Although the project site mentions that it has been tested on Raspberry Pi, I just couldn’t get past one of the steps. A little bit of Googling revealed a possible solution, and it worked. Be warned, the process takes a little while but in my opinion the results are definitely worth it.

Installation of Subversion and the heatmiser-wifi software

To get hold of the software, you have to check it out using the Subversion (SVN) source control system. So the first step is to install SVN:

sudo apt-get install subversion

You can then run the following command to download the heatmiser-wifi software:

svn checkout http://heatmiser-wifi.googlecode.com/svn/trunk/ ~/heatmiser-wifi-read-only

This will create a folder called heatmiser-wifi-read-only in your home directory. If you want to specify a different path, edit the command as appropriate.

Install Perl and essential packages

Check that Perl version 5 is installed by running:

perl -v

This should return some output starting with the following (or similar):

This is perl, v5.10.1 (*) built for arm-linux-gnueabi-thread-multi

If not, install Perl using:

sudo apt-get update
sudo apt-get install perl5

Now you need to install the required packages:

curl -L http://cpanmin.us | perl - --sudo App::cpanminus
sudo cpanm CGI Cwd DBI File::HomeDir Getopt::Std IO::Socket JSON LWP::UserAgent Proc::Daemon Proc::PID::File Time::HiRes
sudo apt-get install libxml-simple-perl
sudo cpanm XML::Simple

This takes a long time, so you may want to have a cup of tea, run a bath or go for a walk!

(Note that the original instructions had the CPAN modules listed on one line, omitting the apt-get before XML::Simple, but this didn’t work for me, hence the change. Also I had trouble getting the standard cpan command to work on the Pi due to its limited hardware, hence using cpanminus instead.)

Test the installation

Run the following command, adjusting the path if necessary, replacing 192.168.0.100 with the actual IP address of your Heatmiser and 1234 with the PIN number:

~/heatmiser-wifi-read-only/bin/heatmiser.pl -h 192.168.0.100 -p 1234

You should get some output like this:

Heatmiser PRT version 1.2
Thermostat is ON (heating mode)
Time 2012-07-07 21:45:59
Temperature 23.5 deg C (internal)
Target 17 deg C
Heating is OFF
Feature 01: Temperature format C
Feature 02: Switching differential 1 deg C
Feature 03: Frost protect 1
Feature 04: Frost temperature 15 deg C
Feature 05: Output delay 0 minutes
Feature 06: Comms # n/a
Feature 07: Temperature limit 0 deg C
Feature 08: Sensor selection internal
Feature 09: Floor limit n/a
Feature 10: Optimum start disabled hours
Feature 11: Rate of change 20 minutes / deg C
Feature 12: Program mode 5/2 day
Weekday 1: 07:00 20 deg C
2: 07:30 17 deg C
3: 17:00 20 deg C
4: 21:30 17 deg C
Weekend 1: 09:30 20 deg C
2: 21:30 17 deg C

For the rest of the steps to work, you need to store the IP address and PIN number in a config file. To do this:

sudo nano /etc/heatmiser.conf

Type the following two lines, substituting 192.168.0.100 with your thermostat’s actual IP address, and 1234 with its PIN:

HOST 192.168.0.100
PIN 1234

Press Ctrl+X and type Y to save the file.

You should now be able to run the following command (same as before but without the IP and password, which will now be read from the conf file).

~/heatmiser-wifi-read-only/bin/heatmiser.pl

Set up the web interface

Happily the project’s web interface instructions seem to work fine on the Pi without any changes.

I have also set up logging and charting of external temperature (via the Met Office API). Frustratingly, my Met Office API key didn’t work straight away – it kept returning Invalid key please register at http://www.metoffice.gov.uk/public/ddc via both the heatmiser_weather.pl script and the “preview data” feature on the Met Office site itself. Also note that it will take up to five minutes for the weather table to start populating, unless you’ve increased the rate in the heatmiser.conf file.

© 2014 Chris Barnes