Letters

On Project Fi

I just finished reading Shawn Powers' "A Look at Google's Project Fi" from the July 2018 issue, and I wanted to chime in from the bus I am currently riding from Siem Reap to Phnom Penh, Cambodia, using my Pixel on Project Fi. One of the greatest benefits for me is the ability to use it in almost every country in the world. I have personally used Project Fi in Japan, Mexico, Singapore, Malaysia, Korea, Cambodia, Singapore and of course the US. I keep a data-only SIM in a spare (non-fi-compatible) phone and use that one via USB tether to a travel router to provide access to several devices when no WiFi is available.

When I can connect to a hotel's WiFi, Google Fi lets me make calls back to the US at no charge.

One more thing: if you set up a Google Voice number, you can use the Hangouts Dialer to make and receive calls from a data-only SIM, and SMS comes through Hangouts. For that to work, you need to use a different account from the one that Fi is set up on.

Regards, and keep up the great work!

—J. Jordan

Shawn Powers replies: I haven't been able to test the international usefulness myself (apart from briefly picking up a Canadian tower when I was in Michigan's upper peninsula). It's great to hear how well it works! Also, the Hangouts tip is great. I could see that being an awesome solution for a family trying to save money with younger kids. That way they still could make calls, but not need a new "line" to do it. Thanks!

More on Project Fi

I liked Shawn Powers' article about Project Fi, but with the restriction to T-Mobile for data only, you also should look into the Ting service as an alternative. It's $6 per phone for the "line" to keep the SIM active, and then everything else is shared and pay-as-you-go. It works on virtually any GSM phone. You can buy the SIM cards at Kroger and so on.

I have a cheap ($60 new) Blu Android 6.0 smartphone that I use with Ting. I use it only for sending text messages from our home security system. The basic $3 for 300 texts means my monthly bill is around $11.27 after taxes, or only $8.27 if no alert texts get sent. This is very much worthwhile for the peace of mind that comes from knowing I'll get alerts even if the internet is down, along with alerts when the AC power goes down and is restored.

Since I was already using MQTT in my home security system, it was easy to install Termux and Termux-API from the play store, node-red using apt-get and then in a web browser create a flow (what node-red calls a program) to accept SMS messages over MQTT and send them out on the Ting /T-Mobile network using Termux-API.

If you can find something cheaper, it'd be fantastic, but I've been looking for a long time. The free FredoomPop service actually meets most of my smartphone needs (100MB/month free data on AT&T, 400MB/month free on Sprint), but they use a "special" VOIP dialer and messaging app that doesn't properly register its "Android Intent", so the termux-node-red SMS messages end up in the default Android Messages App and never get sent.

I'm very happy that LJ has made a comeback!

If you want an idea for an article, take a look at this project I've put up on GitHub: https://github.com/wb666greene/SecurityDVR_AI_addon.

The basic idea is to use a Raspberry Pi3 and Movidius Neural Compute Stick to add AI "person detection" to snapshot images from an existing video security DVR and send "push" notifications via SMS and email with an image when a person is detected when and where they shouldn't be. The Movidius can do about ten images per second. My system has been running for over a month now monitoring eight cameras, and the false alarm rate is effectively zero—the only bogus alerts were when my wife put some hand-washed clothes or a chair on the pool deck, and another was when she put her floppy sun hat on top of the tower fan on the patio—both kind of looked like a person at a quick glance.

I'm also about to put up a project doing a standalone AI-enhanced security camera using a Raspberry Pi (2B or above) and Pi NoIR camera module. It achieves only about one frame every two seconds, but the highly reliable push alerts make it well worth the ~$80 it takes for parts. I've uncovered what seems to be a bug in the openCV dnn module. I'm testing a workaround on two systems as I type this, and if they run for a week or more, I'll put the project up, but I'd prefer to find a real solution to the issue first. I've got questions out, but so far no responses.

—Wally

Shawn Powers replies: Thanks for the tip on Ting. I'll offer another possibility, one that I used last year for our foreign-exchange student: RedPocket. It looks like the price isn't as low as it was when I bought it, but I got an annual contract, with SIM, which had 500MB of data, 500 minutes of voice and 500 text messages per month for $60. It looks like the same deal is $99 now, but maybe it goes on sale. Nevertheless, pre-paid plans are amazing for certain circumstances, and it's nice to see affordable options out there!

As far as the project goes, I'd love to see details about it. Heck, I have a Raspberry Pi sitting on my desk looking for a project. I'll look at your GitHub page and might have some questions for you. I'll be sure to give you accolades if I set up the project!

Regarding Work the Shell, "Shuffling Letters and Words" in the July Issue

Something that works on Mac OSX (or pretty much anything with $RANDOM and bourne-like shell):


cat 1984.txt | sed -e '1i \
cat <<HERE' -e 's/^/\$RANDOM    /' -e '$a \
HERE' | sh | sort | cut -f2

Note: there's a tab after $RANDOM.

—Christopher Cox

Dave Taylor replies: Nice, streamlined solution, Christopher. Thanks for writing in and sharing it!

BirdCam—Image Capture and Classification

To Shawn Powers: I am a fan of Linux Journal and have come across something I think might pique your interest.

I found an article while searching for home automation and security ideas. A guy named Robin Cole created a system to classify images as bird or "not bird" at his home, using a few of your favourite things: birds, bird feeder, Raspberry Pi, Synlogy NAS and a webcam.

You might even be challenged to identify the bird in the image too, who knows.

Have a look here.

As far as I could see, most of it is open source too.

—Hanro

Shawn Powers replies: Whoa, that's awesome! One of the problems I have with my motion detection is false positives. If you watch my nightly archives, you'll see a lot of the "motion" is non-feather-related. I'll have to check it out, thanks for the link!

Question for Kyle Rankin Regarding Odroid Xu4 NAS

Can you please detail the software stack, configuration, and back-up scripts that power your Odroid Xu4/Mediasonic Probox NAS solution? Many thanks,

—Lloyd

Kyle Rankin replies: Thanks for the letter. It's true that I mostly focused on the hardware side of my NAS in my "Papa's Got a Brand New NAS" article. I should do a follow-up column at some point in the future about the software side. In summary, I use an off-the-shelf Debian image and standard NFS and CIFS file-sharing services to share directories with other computers on my network.

From Social Media

Davide Principi @davideprincipi: Old but gold: '97 @linuxjournal article about named pipes: https://www.linuxjournal.com/article/2156!

Containers

Brad Beyenhof @augmentedfourth: @reuvenmlerner I enjoyed your article on Dataclasses in @linuxjournal and I'm interested in your courses. Is there a difference in level/content between "Practice Makes Python" and the Weekly Python Exercise?

Reuven M. Lerner @reuvenmlerner: Replying to @augmentedfourth @linuxjournal Glad you enjoyed it! Practice Makes Python is a course with exercises. You do it on your own, either with or without video instructions/explanations. It's aimed at people who have a more basic background, roughly people who have been through my intro course.

Reuven M. Lerner @reuvenmlerner: Replying to @reuvenmlerner @linuxjournal @augmentedfourth Let me know if you have further questions! You can learn more about WPE at http://WeeklyPythonExercise.com or my courses in general at http://store.lerner.co.il.

Canonical Ltd @Canonical Embracing Snaps: an Interview with @Canonical and @SlackHQ http://bit.ly/2tPNxUH via @linuxjournal

John Nordberg @dgm9704: Replying to @Canonical @linuxjournal @SlackHQ I'm wondering, is it snaps like snapping your fingers, snaps like snapping into place, or snaps like schnapps? ;-)

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