Git – Push to a new remote server repository

Short reminder to myself on how to create a new server repo and do the initial push to it from a workstation.

On the Server:

cd Repositories
mkdir Project.git
git init –bare

On the Workstation:

cd Project
git init
git add *
git commit “Initial commit”
git remote add origin username@server.com/disk/shares/repositories/project.git
git push –u origin master

Done.

Baking Pi – Part 2

The first part of this ‘getting things up and running’ series can be found here.

In this post I wanted to outline what was required to set up Wi-Fi and to get a Microsoft LifeCam 6000 working, providing a web page with the camera image streaming.

So, Wi-Fi… I bought a £6.99 USB Wi-Fi dongle from eBay. After plugging it in and rebooting the Pi I opened a SSH session to it and typed ‘lsusb’ This lists all the usb devices, and I could see the Wi-Fi adapter in the list as a Ralink RT5370.

First thing was to get the drivers – doing an ‘apt-cache search ralink’ found me the correct package (firmware-ralink). On issuing ‘apt-get install firmware-ralink’ it told me that the version I had already up to date – great it seems the Raspbian ‘Wheezy’ image comes with it installed.

So, it was just a case of setting the Wi-Fi options and giving it an IP address (static). I do this directly in the interfaces file. So…

  • From the command line run sudo nano /etc/network/interfaces
  • Change "iface wlan0 inet dhcp" to "iface wlan0 inet static"
  • below this add…
  • address 192.168.97.15
  • netmask 255.255.255.0
  • gateway 192.168.97.1
  • also add the following Wi-Fi options
  • wpa-ssid YOUR_SSID
  • wpa-psk YOU_KEY
  • wireless-power off
  • Now reboot (sudo reboot)

You should now have a Wi-Fi enabled Pi.

lifecam6000For the webcam, things were a little trickier… A lot of people are using ‘motion’ for setting up security cameras, as it does motion detection and can spit out images or movies when some motion is detected as well as do time-lapse and provide a web based video stream for viewing in a browser. However, this was overkill for what I had in mind (just simple streaming of the video), and it also uses a lot of horsepower.
So instead I selected mjpg-streamer, an open source project hosted on SourceForge.

There are no prebuilt binaries for the Pi, so it’s a case of building it yourself – not too difficult…

First get all the dependencies…

  • sudo apt-get install libv4l-dev
  • sudo apt-get install libjpeg8-dev
  • sudo apt-get install imagemagick

I tried installing subversion to check out the code, but the svn urls have moved around and it wouldn’t let me do a checkout as it couldn’t find the correct url, so instead I just downloaded the zipped tarball and extracted it…

At this point I tried to do a ‘make’ but it failed stating it could not find linux/videodev.h. A bit of noodling around found that I had a videodev2.h file, so all that was needed was a symbollic link.

  • ln –s /usr/include/linux/videodev2.h /usr/include/linux/videodev.h

Now to build it…

  • make clean all

I did get a few error towards the end, but the key elements built correctly (I think it was just a plugin or two that failed to build, so I simple glossed over that).

Now you can start the application manually with the following command line:

  • ./mjpg_streamer -i "./input_uvc.so" -o "./output_http.so -w ./www"

.. but what we really want is to start it automatically when the Pi boots so…

  • sudo /etc/init.d/webcam

… and add the following text to it…


### BEGIN INIT INFO
# Provides: mjpg-streamer
# Required-Start: networking
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Starts mjpg-streamer
# Description:
### END INIT INFO

#! /bin/sh
# /etc/init.d/webcam

# Start / Stop the webcam streamer
case "$1" in
  start)
    echo "Starting webcam streaming"
    /home/pi/mjpg-streamer-r63/mjpg_streamer -o "/home/pi/mjpg-streamer-r63/output_http.so -w /home/pi/webcam/mjpg-streamer-r63/www" &
    ;;
  stop)
    echo "Stopping webcam streaming"
    killall mjpg_streamer
    ;;
  *)
    echo "Usage: /etc/init.d/webcam {start|stop}"
    exit 1
    ;;
esac

exit 0

 

Now the final touches of making it executable and making sure it get started…

  • sudo chmod 755 /etc/init.d/webcam
  • update-rc.d webcam defaults

.. and the final part is of course viewing your handiwork – so open a browser and type :8080">http://<your_pi_ipaddress>:8080 and you should be able to see the webcam image.

 

Pi Track – Overview

One of the things I’d been planning on since buying the Raspberry Pi is putting together some sort of robot (for the kids benefit you understand…)

Whilst the Pi does have a bunch of GPIO pins that can be used to interface to motor boards and sensors, the fact it runs on 3.3V and is so sensitive to incorrect voltages  has made me reluctant to interface directly from the Pi to other hardware.
Also the Linux OS isn’t great for some of the time sensitive stuff needed for robotics. I could have run a real time OS on it instead of Linux, but instead I thought I’d have it do the ‘intelligence’ and delegate the simple the motor and sensor control to an Arduino.

So I bought an Arduino Nano (V3.0) – this is a great little device, mini USB input to power and communicate with it, 20 odd IO pins and the like, and the IDE and development software that comes with it make it real simple to get started.
Add to that, the fact you can pick them up for around £10 and it’s a no brainer…

Anyway, I had a play around with both and got them talking to one another over I2C and all was good. At first I had jumper wires all over the place, but I had a spare ‘Humble Pi’ prototyping board so I used that to hardwire a Arduino slave connected to the Pi master, so now I have the best of both worlds…

I also took delivery of a Dagu Rover 5 tracked robotics base, connecting that up to a H Bridge motor controller and driving the H Bridge from the Arduino (based on commands send from the Pi over I2C) all worked without a hitch.

The ‘sketch’ I wrote for the Arduino is pretty simple, it sets the Arduino up as a slave on a particular address and when sent commands reacts to the (‘f’ for forward, ‘b’ for backwards, etc.)
On the Pi side it is a simple bit of C code that waits for user input and sends it over the I2C channel (making use of Gordons wiringPi library).

The outcome, this evening, was a robot that can now move in response to user commands from the Pi SSH session.
I’ll go into more detail about the wiring interconnect and the code for the Pi and Arduino in a future article, but for now here are some images:

2013-08-21 21.21.47    2013-08-21 21.23.17

Here is a view of the Arduino daughterboard thing I hacked together…

2013-08-21 21.23.43

I purchased a couple of Ultrasonic sensors from eBay (around £2.50 each), so future plans include some kind of distance measurement, obstacle avoidance and more autonomy for the bot, rather than ‘remote control’ via a SSH session.

Watch this space for more details…

Baking Pi – Part 1

After starting with a Raspberry Pi that was just too simple to set up as XMBC media centre for daughter #1 bedroom, it soon became a permanent feature there – meaning, of course, that I needed another…

I now have my second helping of Pi – again I got a Raspberry Pi Model B (512MB RAM).

I’m running this mostly headless and wanted to post a few pointers on my setup (so I can recall it when I trash the Raspbian OS and have to restart from scratch.

After a standard Raspbian install I am doing the following actions / configurations :

  1. Basic configuration via raspi-config
  2. Setting a static IP address
  3. Updating all packages
  4. Adding a custom port to listen for SSH on (for remote access through home router)
  5. Setting up vsftpd

Here is the step by step guide:

Basic configuration via raspi-config

  • Make an SSH connection to the device and login (pi / raspberry)
  • From the command line run sudo raspi-config
  • Upgrade raspi-config
  • Configure as required.

Setting up a static IP address

  • From the command line run sudo nano /etc/network/interfaces
  • Change "iface eth0 inet dhcp" to "iface eth0 inet static"
  • imagebelow this add…
  • address 192.168.97.12
  • netmask 255.255.255.0
  • gateway 192.168.97.1
  • Now reboot (sudo reboot)

Updating all packages

  • From the command line run sudo apt-get update
  • From the command line run sudo apt-get upgrade
  • Now reboot (sudo reboot)

Adding a customer port to listen for SSH on

  • From the command line run sudo nano /etc/ssh/sshd_config
  • Add a line under where it says Port 22
  • Type Port xxxx on the new line (where xxxx is your desired additional port number)

Setting up vsftpd (FTP Server)

  • From the command line run sudo apt-get install vsftpd
  • Now edit the config file to change the port is listens on
  • From the command line run sudo nano /etc/vsftpd.conf
  • Under the line that reads listen=YES add the following lines
  • listen_port=xxxx (where xxxx is your desired port)
  • pasv_enable=YES
  • pasv_min_port=yyyyy (where yyyyy is the lower range of ports you want it to use)
  • pasv_max_port=zzzzz (where zzzzz is the upper range of ports you want it to use)
  • Now restart the vsftpd service with sudo /etc/init.d/vsftpd restart

All done. The Pi is now configured to allow SSH and FTP access on custom ports (with corresponding holes through the firewall to allow external access). Enjoy…

Starting with a Raspberry Pi

I eventually got round to ordering a Raspberry Pi Model B (512MB RAM). As you probably know this is a £25 ($35) computer running a 700MHz ARM processor and capable of decoding displaying HiDef 1080p video.

I got one to experiment with as a media player for daughter #1 room, so she could watch the videos / DVDs I’ve ripped to the home server. It took around 30 minutes to realise exactly how easy this would be and how powerful these little babies are.

I wont go into detail, but to get XBMC running on it is a case of downloading the SD card image, writing to the card, plugging it all in and off you go. Testing it on my main TV, I found that I could even control XBMC from the TV remote (CEC over HDMI) – however on daughter #1 TV that didn’t work so I bought one of these remotes : GMYLE® Windows 7 Vista XP Media Center MCE PC Remote Control and Infrared Receiver for Home, Premium and Ultimate Edition : plugged in the IR Receiver and it all worked seamlessly – amazing ‘out of the box’ experience.
I also bought a pink (Raspberry) case with a VESA mount that allowed me to mount it on the back of the TV : Case for Raspberry Pi with adaptor to fit to VESA 100 Monitor – Raspberry Colour

Anyway, it was so easy to use and so well received it is now in constant use – so I needed another to play with… which I also bought. This one I shall be using for projects (robotics with son #1 and fun programming with son+daughter). I’ve already ordered powered USB hub, case, cables, USB sticks and SD cards, as well as a GPIO breakout cable for linking up to a breadboard. Watch this space…