Cool Projects

RV Offsite Backup Update

Kyle Rankin — Wed, 07 Aug 2019 21:15:00 +0000

Having an offsite backup in your RV is great, and after a year of use, I've discovered some ways to make it even better.

Last year I wrote a feature-length article on the data backup system I set up for my RV (see Kyle's "DIY RV Offsite Backup and Media Server" from the June 2018 issue of LJ). If you haven't read that article yet, I recommend checking it out first so you can get details on the system. In summary, I set up a Raspberry Pi media center PC connected to a 12V television in the RV. I connected an 8TB hard drive to that system and synchronized all of my files and media so it acted as a kind of off-site backup. Finally, I set up a script that would attempt to sync over all of those files from my NAS whenever it detected that the RV was on the local network. So here, I provide an update on how that system is working and a few tweaks I've made to it since.

What Works

Overall, the media center has worked well. It's been great to have all of my media with me when I'm on a road trip, and my son appreciates having access to his favorite cartoons. Because the interface is identical to the media center we have at home, there's no learning curve—everything just works. Since the Raspberry Pi is powered off the TV in the RV, you just need to turn on the TV and everything fires up.

It's also been great knowing that I have a good backup of all of my files nearby. Should anything happen to my house or my main NAS, I know that I can just get backups from the RV. Having peace of mind about your important files is valuable, and it's nice knowing in the worst case when my NAS broke, I could just disconnect my USB drive from the RV, connect it to a local system, and be back up and running.

The WiFi booster I set up on the RV also has worked pretty well to increase the range of the Raspberry Pi (and the laptops inside the RV) when on the road. When we get to a campsite that happens to offer WiFi, I just reset the booster and set up a new access point that amplifies the campsite signal for inside the RV. On one trip, I even took it out of the RV and inside a hotel room to boost the weak signal.

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Build Your Own Internet Radio Receiver

Nick Tufillaro — Mon, 27 May 2019 11:00:00 +0000

by Nick Tufillaro

Tune in to communities around the world with the push of a button.

When I get home at night, I like to tune into the world with the push of a button. I've lived in lots of different places—from Dunedin, New Zealand, to Santa Fe, New Mexico—and in each town, I've come to love a radio station (usually a community radio station) that embodies the spirit of the place. With the push of a button, I can get a bit back in sync with each of these places and also visit new communities, thanks to internet radio.

Why build your own internet radio receiver? One option, of course, is simply to use an app for a receiver. However, I've found that the most common apps don't keep their focus on the task at hand, and are increasingly distracted by offering additional social-networking services. And besides, I want to listen now. I don't want to check into my computer or phone, log in yet again, and endure the stress of recalling YAPW (Yet Another PassWord). I've also found that the current offering of internet radio boxes falls short of my expectations. Like I said, I've lived in a lot of places—more than two or four or eight. I want a lot of buttons, so I can tune in to a radio station with just one gesture. Finally, I've noticed that streams are increasingly problematic if I don't go directly to the source. Often, streams chosen through a "middle man" start with an ad or blurb that is tacked on as a preamble. Or sometimes the "middle man" might tie me to a stream of lower audio quality than the best being served up.

So, I turned to building my own internet radio receiver—one with lots of buttons that allow me to "tune in" without being too pushy. In this article, I share my experience. In principle, it should be easy—you just need a Linux distro, a ship to sail her on and an external key pad for a rudder. In practice, it's not too hard, but there are a few obstacles along the course that I hope to help you navigate.

My recipe list included the following:

A used notebook with an ultra low voltage (Core 2 Duo) processor.
An audio interface with an optical TOSLINK.
pyradio: an open-source Python radio program.
An external keypad.

Figure 1. My Hardware Setup

Why a notebook and not a Raspberry Pi or ship of a similar ilk? Mostly due to time—my time in particular. It's not too hard to find a high quality notebook about ten years old for about $50, so the cost is really not that different, and I find the development platform to be much quicker.

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Weekend Reading: Raspberry Pi Projects

Carlie Fairchild — Sat, 13 Oct 2018 11:23:24 +0000

by Carlie Fairchild

The Raspberry Pi has been very popular among hobbyists and educators ever since its launch in 2011. It’s a credit-card-sized single-board computer with a Broadcom BCM 2835 SoC, 256MB to 512MB of RAM, USB ports, GPIO pins, Ethernet, HDMI out, camera header and an SD card slot. The most attractive aspects of the Raspberry Pi are its low cost of $35 and large user community following. Join us this weekend as we explore some cool Raspberry Pi projects.

Raspberry Strudel: My Raspberry Pi in Austria by Kyle Rankin: In this article, I explain how I was able to colocate a Raspberry Pi and the steps I went through to prepare it for remote management.

Raspberry Pi: the Perfect Home Server by Brian Trapp: If you've got several different computers in need of a consistent and automated backup strategy, the RPi can do that. If you have music and video you'd like to be able to access from almost any screen in the house, the RPi can make that happen too. Maybe you have a printer or two you'd like to share with everyone easily? The Raspberry Pi can fill all those needs with a minimal investment in hardware and time.

Securi-Pi: Using the Raspberry Pi as a Secure Landing Point by Bill Childers: Set up a Raspberry Pi to act as an OpenVPN endpoint, SSH endpoint and Apache server—with all these services listening on port 443 so networks with restrictive policies aren't an issue.

Real-Time Rogue Wireless Access Point Detection with the Raspberry Pi by Chris Jenks: A couple years ago, I decided to go back to school to get a Bachelor's degree. I needed to find a single credit hour to fill for graduation. That one credit hour became an independent study on using the Raspberry Pi (RPi) to create a passive real-time wireless sensor network. I share my work with you here.

Flash ROMs with a Raspberry Pi by Kyle Rankin: In this article, I describe the steps I performed to turn a regular Raspberry Pi running Raspbian into a BIOS-flashing machine.

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Smart-Home Lightning Hacks

Shawn Powers — Mon, 14 May 2018 11:30:00 +0000

by Shawn Powers

Home automation should make life simpler, not more complex!

Kyle Rankin occasionally uses the "lightning hacks" format for his Hack and / LJ column when he has a bunch of neat topics to cover that wouldn't be enough for a complete article on their own. Thinking along those lines for this article, I figured it would be great to cover various home-automation stuff I do. Not only is it fun to share ideas, but if I make a list of all the cool things I'm currently doing, it will make it easier to compare the functionality of open-source options I'd like to explore next. If you haven't been dipping your toes into the world of home automation, maybe some of these hacks will change your mind.

My Setup

Most home-automation ideas can be implemented in multiple ways. In fact, I'm counting on that as I look into less-proprietary methods in the near future. But right now, I'm using a Samsung SmartThings hub. Yes, it is proprietary, but Samsung really has opened up the API and allowed developers to create device drivers and apps to customize the platform. I think SmartThings is the most feature-complete solution for home automation right now, but it does have a few frustrations. The most annoying is that it requires a constant connection to the internet in order to function. Most folks are frustrated with the inherent privacy concerns of home automation taking place in the cloud, and that's a big problem. For me, the more frustrating aspect is the effect shoddy internet service has on a home. If the internet goes down, so does 90% of my house! I have a few workarounds, but I know that a solid (not fast) internet connection is vital if your solution is cloud-based like SmartThings.

Anyway, my setup consists of the following:

Samsung SmartThings Hub v2.
Amazon Echo devices all over the house.
Google Home devices all over the house.
Sonos speakers in most rooms.
Various lights, switches, sensors and so on.

Having both Amazon Echo and Google Home isn't something I encourage; it's just that I have a habit of trying new technology, and they are both so amazing, I haven't yet chosen one over the other. Thankfully, they're pretty happy to function together.

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Creating an Internet Radio Station with Icecast and Liquidsoap

Bill Dengler — Mon, 15 Jan 2018 14:34:13 +0000

by Bill Dengler

Ever wanted to stream prerecorded music or a live event, such as a lecture or concert for an internet audience? With Icecast and Liquidsoap, you can set up a full-featured, flexible internet radio station using free software and open standards.

Icecast is "a streaming media (audio/video) server that currently supports Ogg (Vorbis and Theora), Opus, WebM and MP3 streams. It can be used to create an internet radio station or a privately running jukebox and many things in between. It is very versatile in that new formats can be added relatively easily and supports open standards for communication and interaction."

Liquidsoap is "a powerful and flexible language for describing your streams. It offers a rich collection of operators that you can combine at will, giving you more power than you need for creating or transforming streams. But Liquidsoap is still very light and easy to use, in the UNIX tradition of simple strong components working together."

When combined, Icecast and Liquidsoap can create a flexible, feature-rich internet radio station. In this article, I describe how to configure Icecast to host an internet radio station. Then, I explain how to install and configure Liquidsoap to connect to Icecast, adding random (or sequential) music playback with smart cross-fading, prerecorded randomly inserted announcements and jingles, a song request system and support for live streams, with automated recording and seamless switching between live and automated programming. I also show how to configure the server to serve your stream in MP3, Ogg and Opus formats for maximum player compatibility.

Icecast, Vorbis and related projects are maintained by Xiph.Org, a nonprofit organization that develops open multimedia standards and software. To ensure that you are running the latest version of Icecast, with all (or most) features, you should install from an official Xiph.Org repository. Visit the list of official repositories here, and follow the instructions on that page to add the Icecast repository for your distribution. Then, install using your system's package manager. On Debian-based systems (such as Ubuntu), you may be asked to "configure Icecast" during package installation; select "no" as you will configure the server manually if you are following along with this article.

Open the Icecast configuration file using your preferred text editor. On Debian-based systems, the file is located at /etc/icecast2/icecast.xml. The location on other systems may differ; check your package's documentation for the correct path. The configuration file is in XML format and is divided into several sections. First, enter your server's location and email into the location and admin fields, respectively—for example:

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Live Stream Your Pets with Linux and YouTube!

Shawn Powers — Thu, 26 Oct 2017 11:53:25 +0000

by Shawn Powers

Anyone who reads Linux Journal knows about my fascination with birdwatching. I've created my own weatherproof video cameras with a Raspberry Pi. I've posted instructions on how to create your own automatically updating camera image page with JavaScript. Heck, I even learned CSS so I could make a mobile-friendly version of BirdCam that filled the screen in landscape mode.

Recently, however, I've finally been able to create an automated system that streams my BirdCam live over YouTube. It starts when the sun comes up and stops when the sun goes down. And thanks to some powerful open-source software, I never have to touch the system!

Some of the tools I describe here have been covered in other articles, but this is the first time I've been able to create a stream that anyone can see utilizing bandwidth Google pays for!

Figure 1. Birds are always camera-shy. If you watch long enough, however, they come and steal peanuts!

My List of Ingredients

First off, I want to be clear about what sort of hardware and software is required in order to accomplish something similar to what I'm doing:

A Linux computer: if you plan to use USB cameras, this needs to be a physical computer. If your video source is network-based, this can be a virtual machine on your network. A Raspberry Pi isn't really powerful enough for the video work that has to be done, unless maybe it's low-resolution. I have an old i5 CPU running at 1.6GHz, and it's more than enough.
A video source: this can be pretty much any video source you have at hand. If you plan to use a USB webcam, you'll need to be sure you are using a physical Linux computer as noted above. I've used USB, MJPEG over http (see my old BirdCam articles), cheap wireless security cameras that have an RTSP stream, and most recently, I started using UniFi video cameras. In fact, if you are considering purchasing outdoor video cameras for a project like this, I can't recommend UniFi cameras enough. They are PoE, HD and the free software handles recording and provides RTSP streams that have both HD video and top-notch audio.
A YouTube account with Live Streaming enabled: you'll need to verify your account, and then enable live streaming here. It's not a difficult process, but without following those steps, you won't be able to use the free service.

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The Weather Outside Is Frightful (Or Is It?)

Derek Hildreth — Fri, 03 Feb 2017 15:03:11 +0000

by Derek Hildreth

Blistery cold weather is sinking in, which ought to ignite an instinctual desire to get your house in order and monitor it so the water pipes don't freeze and burst. So, let's take a timely look at a project setting up some temperature probes in various areas, reading them and reporting in a custom dashboard. A true home automation expert would take things further by setting up relays to turn on heat tape or even maybe some actuators to control water flow. Maybe next year, but for now, we just want to be able to monitor important areas of our home (in this case a cabin in Montana) and understand temperature patterns over time for better planning. As with most projects, there is more than one solution, especially if it depends on what you have on hand. At the time, the list of things in hand were as follows:

4x temperature sensors (thermocouples).
1x RS-232 thermocouple module, specifically the DGH D5331.
1x TS-7500 single board computer with TS-752 and enclosure.
1x USB thumbdrive for storage.
Various wiring, including Ethernet.
1x DB9 male to RJ45 female adapter.
1x web server (desktop, virtual machine or cloud-based).

If you're interested in doing something like this, I'd look into using any temperature sensor that uses the DS18B20 IC (or something like it) and use the TS-1700 temperature sensor module with modbus and TS-7680 single board computer. You'd save some money and double the number of temperature sensors you could use.

Overall, image below shows what we're looking to build.

Four temperature sensors connected to a thermocouple module that is read using a single board computer acting as an SFTP file server. A web server in a different location is able to access the file server to store temperature data in its own database and present a nice-looking dashboard to an end user. This project guide is going to skim over the hardware setup, highlight a Python script that reads temperature data over RS-232 and spend some time on setting up an HTML dashboard using Google Charts. Hopefully it'll inspire your next project.

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Gordon H. Williams' Making Things Smart (Maker Media, Inc.)

James Gray — Wed, 25 Jan 2017 15:48:27 +0000

by James Gray

Pretty much anything in the O'Reilly spin-off Make: series is like catnip to us Linux cats, and the new book Making Things Smart is no exception. The book is subtitled Easy Embedded ARM Programming For Transforming Everyday Objects Into Intelligent Machines and is authored by Gordon H. Williams.

The book is Williams' tool for teaching readers the fundamentals of the powerful ARM microcontroller by walking beginners and experienced users alike through easily assembled projects composed of inexpensive, hardware-store parts.

In rebellion to the many current ARM programming books that take a bland, textbook-ish approach with focus on complex, beginner-unfriendly languages—think C or ARM Assembler—Making Things Smart utilizes Espruino (JavaScript for Hardware) to flatten the learning curve.

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My Childhood in a Cigar Box

Shawn Powers — Tue, 17 Jan 2017 10:49:45 +0000

by Shawn Powers

I grew up in the 1980s. That meant we drank far too much Kool-Aid, and on Saturday mornings, we got up early to watch cartoons. It also was the heyday of arcades, but I lived in the ghetto of Detroit and couldn't afford quarters to play games. Plus, there were none anywhere near the neighborhood where I lived. For me, the first real video-game experience was the Atari 2600. I played a lot of Frogger, Pac-Man and Yars' Revenge in middle school. The first system really to impact me, however, was the original Nintendo Entertainment System (NES).

My family moved to northern Michigan when I was in eighth grade, and I worked all summer to save for a used NES from one of the kids who got a brand-new Super Nintendo from his parents. I was a poor nerdy kid who moved in the middle of eighth grade, so my group of friends was fairly small. I had exactly one friend. There happens to be two controllers with a Nintendo, so it worked out perfectly for Pete and me. While the arcade system I built back in 2007 (my first Linux Journal article) may have been to relive the 1980s, this article's project is really a better look at my actual childhood. And this article's project is awesome!

The Goal

My end goals for this project are the following:

Play Nintendo and Super Nintendo games using emulation on a Raspberry Pi.
Fit the project into a wooden cigar box (because I already have a cool wooden cigar box).
Use original NES and SNES controllers, not USB knockoffs.
Boot up, select and play games using nothing more than the controller for navigating menus.
Plug controllers into emulation machine using either original connectors or RJ-45 plugs.
Have a good way to turn the machine on and off, not just unplug it.
Support HDMI, because that's what all televisions and projectors use now.
Support game state saves and restores. (Yes, it's cheating, but I'm more than 40 years old, so if I want to save myself 40 hours of play every time I get to a boss level, I'm gonna do it!)

Thanks to the size of the Raspberry Pi, it's possible to build a project like this into just about anything. I don't have an NES case anymore, but if I did, I'd probably build it inside one for added nostalgia.

I decided to use RetroPie as the distribution for my project. The great thing about using RetroPie is that it basically solves all the issues on my list. It has the "Emulation Station" front end built right in (Figure 1), which supports navigation via controller. It also has emulators already installed, waiting for ROMs to be added. Truly, using RetroPie as my base saved at least one article on software alone!

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The Tiny Internet Project, Part III

John S. Tonello — Thu, 22 Dec 2016 16:43:18 +0000

by John S. Tonello

In a previous article, I introduced the Tiny Internet Project, a self-contained Linux project that shows you how to build key pieces of the internet on a single computer using virtualization software, a router and free open-source applications. In the second installment, I explained how to set up the host server using Proxmox and build a first basic Ubuntu 14.04 virtual machine. In this third installment, you'll learn how to set up an Ubuntu mirror, a DNS server, a mail server and a web server.

As you finished with Part II, you hopefully had just booted a raw Ubuntu 14.04 server VM. Now, I'll describe how to customize that VM with some user accounts and software, keeping it fairly generic, but ready to become a template for most everything else you'll build.

Initially, you'll do all your work from the Proxmox web interface on your Proxmox server: https://10.128.1.2:8006.

Log in and start the Ubuntu VM you made, which probably was named "100 (ubuntu)". Wait a moment for it to boot, and click the Proxmox Console button to launch what is essentially a web-based terminal.

Figure 1. Ubuntu Installation Screen—Selecting Your Language

When the shell opens, you'll see the Ubuntu installation screens. Select your language and choose "Install Ubuntu Server" from the action list. You'll be prompted again for language choices and keyboard layouts; choose the ones that suit your needs. The installer will detect your network and prompt you to enter a hostname.

Figure 2. Entering a Hostname

Since you'll be making this VM a template, give the machine a generic hostname like "ubuntu". That way, if you later deploy a different type of server (say, ArchLinux), you'll easily be able to tell them apart.

When you're asked to create a user name, choose something that follows a naming convention you can use for all future users, such as your first initial and your full last name. Then when you need to figure out user names (and email addresses) later, you won't have to guess.

Figure 3. Selecting a User Name

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