First of course you need a Raspberry Pi (you may already have one, or many of them.., so in this case just skip this step..). If you never heard about it, it is basically a credit-card sized Linux box, and you can find all about it at www.raspberrypi.org. If you need to buy one you have to also buy the power supply. A plastic case is strongly recommended. Also, get the Model B, which has 512Mb RAM.
Total Cost: Under $90
You'll need a 32 GB SD flash memory card, to host the operating system and the RACHEL-Pi educational package. It is recommended to get a fast card. For instance, I use for RACHEL-Pis a SanDisk Extreme 32 GB SDHC Class 10 card, which has up to 45 MB/s read-write speeds.
Don't try to save money on the SD card/s. A known name brand, with fast read-write speeds, will save you a lot of headaches when used with a Raspberry Pi.
Think of the image as an exact copy of the whole hard drive of your PC or Mac, everything in just one file. In this case you will use this "image" file to then burn it, or write it, to your own SD card, making so an exact clone of an original RACHEL-Pi server SD card I have with me. You are going to download it by FTP, in a compressed zip file:
A very good and free FTP client for Windows, Mac and Linux is FileZilla ( filezilla-project.org). It has very important features (Keep-alive, auto reconnect) for downloading very large files like this.
Sample FTP login using FileZilla:
Once connected you'll see the files in the server available for FTP download. Go to the "rachel" folder and drag the rachel_pi_32_20130924.img file to a folder in your computer. This file, of about 32 GB size, contains an instance of the RACHEL Raspberry Pi image. Example using FileZilla on Windows:
The FTP download will start.
WARNING: This is a very large file, 32 GB, which may take a very long time to download, many hours if you don't have a fast Internet connection.
Important: if you want to verify the integrity of the very large downloaded file, which is strongly recommended to make sure that it has arrived intact during the long download process, this is its md5 checksum:
To verify if the MD5 checksum of the downloaded file matches the checksum of the original file (listed above) you can use on Windows a free tool like WinMD5Free (www.winmd5.com). Sample screenshot:
Sample setup with a $45 consumer wireless router:
pi@raspberrypi ~ $ ifconfig eth0 Link encap:Ethernet HWaddr b8:27:eb:ce:67:31 inet addr:10.0.1.20 Bcast:10.0.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1The IP address in the example above is 10.0.1.20
The latest RACHEL-Pi image already includes all the software necessary to use the Raspberry Pi as a Wi-Fi hotspot. This pre-configured software is running all the time on your RACHEL-Pi package: You just need to plug a USB WiFi Adapter to a USB port and start the Raspberry Pi.
It will automatically create a Wi-Fi hotspot called "RPI", to which you can connect from any Wi-Fi enabled device, like a tablet, laptop or smart phone, and access wirelessly the RACHEL content, without the need to use any other network device, like a wireless router. Perfect for an instant setup of a wireless educational hotspot.
Another advantage is that you'll need just the Raspberry Pi power adapter and cable, which will in this case power the Raspberry Pi computer and the USB dongle-based Wi-Fi hotspot.
Sample supported adapters:
Note: The above Wi-Fi setup can be used together with the previous network setup. So you can have the Raspberry Pi running RACHEL-Pi connected via network cable with a router and at the same time running the Wi-Fi hotspot from the Pi. So some students can connect to the local network setup by the router and to the "RPI" wireless network created by the USB Wi-Fi adapter.
This "Khan Academy on a Stick" content included in RACHEL, with almost 3,000 video lectures, uses HTML 5 video in mp4 format using H.264 video and AAC audio codecs. So to be able to play these videos you need to use an modern HTML 5 compatible browser version that also supports this video format.
You can see a list of supported browsers here The ones under the H.264 column and highlighted in Green are very likely to play fine the videos in this distribution.
For instance, as per today, Windows Internet Explorer 9+ and Chrome work great. Latest versions of Firefox (22+) for Mac and Windows work fine also. On the Mac, Safari, Chrome and Firefox 22+. On iOS devices (iPads, iPhones, iPod Touch) everything plays great with OS Safari: the videos can also be expanded full screen, rotated, etc. On Linux Chrome and Konqueror, on Android, well, it is a long story.., but please try yourself (there are at this time thousands of combinations of hardware-Android software versions out there. On some quality ones they play great for instance with Firefox for Android.)
Other pieces of content part of RACHEL include Flash animations, which will be played as well by the above browsers. Though those Flash animations won't play on iOS devices (iPads, iPhones) as Apple does not support Adobe Flash on iOS.
Please do not hesitate to contact us should you have problems to download or setup RACHEL-Pi. You can contact us as described in the About page and we'll be happy to respond.