Archive for October, 2013

Pi Pod from @cpc_tweet

Posted: October 31, 2013 by schoolpiclub in General News

Just purchased the Pi Pod Camera mount from CPC. It’s fits great with my Joby GorillaPod which keeps the Raspberry Pi safe.

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The Raspberry Pi infrared camera module ‘Pi NoIR’ is now available.

Just found this timelapse video that has been taken of a lawn. Check out the speedy slippery slugs!

After seeing a recent tweet from @GeekGurlDiaries we did the Python Fortune Teller task during today’s lunch club.

It went down really well and everyone took turns to have their fortunes read. JS was told he would ‘win a big prize soon’ and it just so happens to be Attendance and Achievement week….finger crossed!

We also welcomed a new member to the group today who also improved his literacy skills whilst taking charge of inputting the code.

A very successful 40 mins!

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Raspberry Pi on iPad

Posted: October 13, 2013 by schoolpiclub in General News, Raspberry Pi Camera
Tags: , , ,

Raspberry Pi on iPad

It’s easy to set your iPad as a screen for your Raspberry Pi using VNC (Virtual Network Connection). Your Raspberry Pi will need to be connected to a network, either by ethernet or wireless.

1. First of all find out the IP address of your Raspberry Pi. I am using a Wi-Pi dongle to connect to the internet so I opened up the WIFI config and that told me my IP. You can also type the following into LX Terminal and that will reveal your IP.

sudo ifconfig

2. Install a VNC server program on your Pi. You can do that with the following commands:

sudo apt-get update
sudo apt-get install tightvncserver

You will be prompted to confirm installation by typing “Y’.

3. After you successfully installed VNC server you can now start a VNC server session with the following line:

vncserver :1

You will be prompted to enter and confirm a password. It would make sense to use “raspberry” for this, but passwords are limited to 8 characters, so I used “raspberr”. Note that this is the password that you will need to use to connect to the Raspberry Pi remotely.

You will also be asked if you want to create a separate “read-only” password – say no.

From now on, the only command that you need to type within your SSH to start the VNC server will be:

vncserver :1

The VNC server is now running and so we can attempt to connect to it via an iPad.

4. On your iPad you need to install the ‘Mocha VNC Lite’ app which is free to download. Once installed you need to configure it.

  • Select ‘New…Add a configuration’
  • In the VNC Server address type in your Raspberry Pi’s IP address.
  • Change the VNC Server Port number to 5901
  • Enter the VNC Password ‘raspberr’ (or which ever you chose)
  • Now select ‘connect on the left hand menu
  • Then choose click the Raspberry Pi’s IP

Your Raspberry Pi’s desktop should now be displayed.

Raspberry Pi on iPad 2

Apple Timelapse

Posted: October 13, 2013 by schoolpiclub in General News, Raspberry Pi Camera

When an apple is sliced or bitten into and exposed to the open air, chemicals within it combine with oxygen and make the apple turn brown. Here is our timelapse video of an apple turning brown.

Apple Timelapse

We set the Raspberry Pi camera to take a picture every 5 seconds for 30 minutes, which is a total of 360 photos.

raspistill -o myimage_%04d.jpg -tl 5000 -t 1800000

Timelapse

Raspistill Arguments

Posted: October 13, 2013 by schoolpiclub in General News, Raspberry Pi Camera

Here is an example of a Raspistill command for a constant stream of jpeg images:-

$ raspistill -w 640 -h 480 -q 5 -o /tmp/stream/pic.jpg -tl 100 -t 9999999 -th 0:0:0 &

Now let’s take a look at the arguments for Raspistill one by one:-

-w  sets the image width. For an HD stream use 1920 here.

-h   sets the image height. For an HD stream use 1080 here.

-q   sets the JPEG quality level, from 0 to 100. I use a pretty low quality, better quality generates bigger pictures, which reduces the frame rate.

-o    sets the output filename for the JPEG pictures. I’m sending them to a temp directory. The same file will be rewritten with updated pictures.

-tl   sets the timelapse interval, in milliseconds. With a value of 100 you get 10 frames per second.

-t    sets the time the program will run. I put a large number here, that amounts to about two hours of run time.

-th  sets the thumbnail picture options. Since I want the pictures to be as small as possible I disabled the thumbnails by setting everything to zero.

&   puts the application to run in the background.

If you are interested in setting up a stream from your Raspberry Pi camera  to web browsers or even iOS or Android devices please visit this link for more details. http://blog.miguelgrinberg.com/post/stream-video-from-the-raspberry-pi-camera-to-web-browsers-even-on-ios-and-android

To playback videos on our Raspberry Pi we installed OMXplayer. This is a media player created by Edgar Hucek specifically for the Raspberry Pi.

Instructions to install

Omxplayer is installed on the latest Raspbian image so you may already have it installed. If not you can install it via LX Terminal using :

sudo apt-get update
sudo apt-get -y install omxplayer

Video Playback

To play a video file you just need to type the following into LX Terminal :

omxplayer myvideo.mp4

If you are using HDMI you should use this command to pass audio over the HDMI interface :

omxplayer -o hdmi myvideo.mp4