Amateur Radio Exam Prep: Technician is an iOS app for iPhone and iPad to help you pass the ham radio technician exam. I am taking the exam to get my license so that I can legally use 5.8GHz video transmitters for first-person view remote control flying.
This app with a good study guide should easily get you through the technician exam. I read a study guide and took about 100 practice exams before taking the test and only missed 2 questions.
I think the best feature of the app is the ability to see the questions you have missed after taking a bunch of test exams so that you can see exactly where you are falling short. That was invaluable to me and the only reason I did as well as I did.
If I decide to take the general exam I will definitely be buying the app for that test also.
I rate Amateur Radio Exam Prep: Technician a 10 out of 10 and recommend it to anyone preparing to take the Technician exam.
This is the Raspberry Pi book I have been looking for. Instead of trying to push some advanced scripting language or Linux distribution, this book shows you how to use the most widely used distribution, Raspbian, and good old Bash scripts to do useful things with a Raspberry Pi.
Now 3 years old the lessons in Learn Raspberry Pi still hold up. Raspbian has been through some major updates and the new Model A+ and B+ computers have added to the Pi’s capabilities, but the Linux/Unix commands, SSH and VNC techniques, network information, Web Server installation (LAMP), and a decent chapter covering compiling XMBC on your Pi.
This book does not cover any topics in depth, but it includes enough information to give you an idea of what to enter into Google to find out more. This is one of the greatest features of Linux and the Raspberry Pi, once you know what to search for, there is more information available for free. The community is made up of millions of people from all over the world that want to share what they have learned and what they have created.
From the publisher:
Learn Raspberry Pi with Linux will tell you everything you need to know about the Raspberry Pi’s GUI and command line so you can get started doing amazing things. You’ll learn how to set up your new Raspberry Pi with a monitor, keyboard and mouse, and you’ll discover that what may look unfamiliar in Linux is really very familiar. You’ll find out how to connect to the internet, change your desktop settings, and you’ll get a tour of installed applications.
Next, you’ll take your first steps toward being a Raspberry Pi expert by learning how to get around at the Linux command line. You’ll learn about different shells, including the bash shell, and commands that will make you a true power user.
Finally, you’ll learn how to create your first Raspberry Pi projects:
Making a Pi web server: run LAMP on your own network
Making your Pi wireless: remove all the cables and retain all the functionality
Making a Raspberry Pi-based security cam and messenger service: find out who’s dropping by
Making a Pi media center: stream videos and music from your Pi
Raspberry Pi is awesome, and it’s Linux. And it’s awesome because it’s Linux. But if you’ve never used Linux or worked at the Linux command line before, it can be a bit daunting. Raspberry Pi is an amazing little computer with tons of potential. And Learn Raspberry Pi with Linux can be your first step in unlocking that potential.
What you’ll learn
How to get online with Raspberry Pi
How to customize your Pi’s desktop environment
Essential commands for putting your Pi to work
Basic network services – the power behind what Pi can do
How to make your Pi totally wireless by removing all the cables
How to turn your Pi into your own personal web server
How to turn your Pi into a spy
How to turn your Pi into a media center
Who this book is for
Raspberry Pi users who are new to Linux and the Linux command line.
I rate this book an 8 out of 10 and highly recommend it to anyone looking to make a project with a Raspberry Pi.
Boris, the BeagleBoard Logo MascotI initially bought an Edimax EW-7811Un Dongle for use with my BeagleBone Black (BBB), but after a lof of fiddling and frustration I gave up on it. Turns out that I may have been using the wrong setting in the interfaces file, but after some research I found many instances of people complaining about the Edimax dongles in general, so I started looking for solutions that others were having good luck with.
Along with a lot of email threads I found WiFi Adapter http://www.elinux.org/Beagleboard:BeagleBoneBlack#WIFI_Adapters recommendations on the Embedded Linux Wiki BBB page. http://www.elinux.org/Beagleboard:BeagleBoneBlack After searching Amazon for the listed adapters I chose the NETGEAR N150 Wi-Fi USB Adapter (WNA1100) http://www.amazon.com/gp/product/B0036R9XRU/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 for $17.50, not the cheapest of the bunch but it comes with a "Desktop Dock" that is basically an USB extension cable which sounds good to me as it will let me place the adapter a distance away from the BBB to get the best WiFi signal.
With the latest build of Debian I was able to get the WNA1100 adapter to work just by editing the interfaces file and rebooting the BeagleBone. Pretty awesome!
Steps
Plugged the BBB into the computer with a USB cable and plugged in a power supply.
Logged into the BBB with the root account with my “fish” "ssh [email protected]"
# sudo nano /etc/network/interfaces and edited the "WiFi Example" to match my network ID and password
This is what the finished WiFi part of the file looks like:
# WiFi Example
auto wlan0
iface wlan0 inet dhcp
wpa-ssid "ssid"
wpa-psk "password"
And BANG! it worked. I am now enjoying WiFi with my BeagleBone Black!
Unable to Connect to BeagleBone Black via Ethernet
Everything works fine when the BeagleBone Black is connected to a computer via USB but when connected to the network via Ethernet it does not work. I ran into this issue when I first started using my BeagleBone Black out-of-the-box and again when I updated the OS to Debian.
Here is the solution:
Connect the BBB to your computer via USB and give it time to boot
In a web browser open the Cloud9 IDE by going to http://192.168.7.2:3000/. You may be prompted to choose some settings, I like the defaults.
Create a new file, paste in the script below, and run it
var fs = require("fs");
var destroyed_key_file = "/etc/dropbear/dropbear_rsa_host_key";
fs.readFile(destroyed_key_file, function (err, data) {
if (err) throw err;
if( data===null || data.length===0 )
{
console.log("we have a corrupted host key file... try do delete it");
fs.unlink(destroyed_key_file, function (err) {
if (err) throw err;
console.log("successfully deleted " + destroyed_key_file);
console.log("you should now reboot your beaglebone.");
console.log("the /etc/init.d/dropbear script will create a new rsa host key file for you.");
console.log("after the reboot you should be able to login over ssh");
});
} else {
console.log("it seems that you have another problem, sorry");
}
});
Now shutdown, I like to sudo shutdown -hP now, the USR lights will all go out when it is shut down
Now you can unplug the BBB from USB and plug in an Ethernet cable and power adapter.
You should now be able to access the BBB from anywhere on your network using http://beaglebone.local or ssh beaglebone.log.
After updating the operating system to Debian and plugging in your BeagleBone Black via USB you may receive the error message: WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
This is normal as the RSA key has changed when you updated the OS.
The easiest way to fix it is to run ssh-keygen -R then try connecting again.
When connected via USB ssh-keygen -R 192.168.7.2 ssh [email protected]
When connected via Ethernet ssh-keygen -R beaglebone.local ssh [email protected]
You should then be asked to add the new fingerprint to your "known hosts", say yes and you should then be asked for your Debian password who’s default is temppwd.
This post is about installing Debian (BeagleBone Black – 2GB eMMC) 2014-03-27 and Flashing the eMMC using a Mac running OSX 10.9 Mavericks.
I decided to get a head start on using Debian with the BBB which is soon to tbe the default OS installed on them.
These are the steps I used today to get up and running:
Download image from http://beagleboard.org/latest-images
– BBB-eMMC-flasher-debian-7.4-2014-03-27-2gb.img.xz
Use Unarchiver to extract disk image
– BBB-eMMC-flasher-debian-7.4-2014-03-27-2gb.img
Download PiFiller to copy the disk image to the SD card
– http://ivanx.com/raspberrypi/ WARNING: Do not insert the SD card yet, PiFiller will tell you when
Run PiFiller and follow the directions
Choose the disk image
Insert the SD card
Verify that PiFiller has found the correct device
Some more verifying, click OK a couple of times
Now wait awhile, it took about 20 minutes on my MacBook Pro Holy Cow! The dialog box opening and closing gets really annoying to watch!
All set when you get the “Your SD card is ready” message
Eject the SD from the Mac OS then remove it from the computer
With the BBB unplugged, no network, USB, video, power cables, insert the SD card into the BBB WARNING: The SD card pokes out of the back of the BBB enough that it is easy to bump it and cause it to eject. Especially when plugging in a USB or HDML cable. It pays to be slow and patient when manipulating the BBB with an SD card in place.
Get ready: When plugging in the BBB you will need to hold down the Boot button until all 4 USR lights turn on
– While holding down the Boot button insert a 5V 2A power supply, release the Boot button when all 4 USR lights turn on
Now the USR buttons should start blinking in a seemingly random pattern, this should go on for 20 to 60 minutes depending on the OS and SD card
When the USR lights all light-up again the eMMC has been flashed with Debian
Remove the power adapter
Remove the SD card
You are now ready to plug-in the devices you want to work with and enjoy Debian
BeagleBone Black is a $45 MSRP community-supported development platform for developers and hobbyists. Boot Linux in under 10 seconds and get started on development in less than 5 minutes with just a single USB cable.
I recommend the book as a good starting point, it does a great job of introducing the basics of the board and using Python and JavaScript to program it. There aren’t many other books out there, but I am not sure there needs to be.
I also bought a power supply, a very cool case, and a wi-fi dongle from Amazon.
The case is pretty awesome. It is very well made and lets you see right into the board with risers for the buttons that make it much easier to press them. The BegaleBone Black should ship with a case like this. It looks like Laser Goodies has pulled their products from Amazon, or maybe they are just out of stock, here is the page on their website Beaglebone Black Slim Case – Clear
Laser Goodies Beaglebone Black Slim Case – Clear
Why I Bought It
I regularly attend the wonderful Atlanta JavaScript Meetup group and a couple of weeks ago Tim Kadom of Thoughtworks showed us his Telepresence robot built with a BeagleBone black and an iPhone. All of the code was written on the BBB with the Cloud9 IDE in JavaScript. I was seriously intrigued.
I have been playing with Ardunio microcontrollers for awhile now and really like them. But they require that you program in their own C like language which I can muddle through but don’t really like. And it is not easy getting an Ardunio on a network, the code to make Ethernet, Wi-Fi, or Bluetooth to work doesn’t leave much space for your own ideas.
The Rasberry Pi on the other hand just doesn’t speak to me. I am more interested in them now that I have spent some time with a BeagleBoard, but I still don’t think I have much of a use for a Rasberry Pi right now.
With the BeagleBone it appears that I get all of the inputs and outputs of an Arduino while having all of the network abilities of a Rasberry Pi that I can program using JavaScript. That really gets me excited!
In the coming weeks I will be posting more about the BeagleBone Black and the project I am working towards.
Amateur Radio Exam Prep: Technician is an iOS app for iPhone and iPad to help you pass the ham radio technician exam. I am taking the exam to get my license so that I can legally use 5.8GHz video transmitters for first-person view remote control flying.
This is the Raspberry Pi book I have been looking for. Instead of trying to push some advanced scripting language or Linux distribution, this book shows you how to use the most widely used distribution, Raspbian, and good old Bash scripts to do useful things with a Raspberry Pi.
