Author: andy

Pi-hole® Ad Blocker runs great on the ODROID C2

I decided to try the Pi-hole® network-wide ad blocking service on a ODROID C2 SBC. I Googled around and saw mention of this running on ODROIDs but no specific “how-to” info. I know it runs well on a Raspberry Pi as I tried that 🙂 The ODROID C2 has more power, memory and network bandwidth so it should be (and IS) a great host.

In case you don’t know, Pi-hole is a network-level advertisement and internet tracker blocking service which acts as a DNS sinkhole and optional DHCP server for use on a local/private network. You setup your computers to use the Pi-hole host as the DNS server — and your done! It also provides a great web interface dashboard for options and status.

Installing Pi-hole on an ODROID C2 running Ubuntu is very straightforward. You can use the instructions from Git: https://github.com/pi-hole/pi-hole


git clone --depth 1 https://github.com/pi-hole/pi-hole.git Pi-hole
cd "Pi-hole/automated install/"
sudo bash basic-install.sh

If you end up using Pi-hole, please support its development. Donation info is available at the Git URL above.

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Insert webcam image into a webpage

Raspberry Pi Zero W with camera in official case

I had the need to embed a webcam image in a webpage. I did not want to stream video and did not want to view images directly on my Raspberry Pi. I wanted to take a picture every so often and upload the image onto a website. I also wanted the webpage to update with the latest image. One other requirement was for the webcam to (try to) survive power outages without file system corruption and with auto-start at boot/reboot. Yet another Raspberry Pi Zero project was born!

I will assume that you have setup a Raspberry Pi Zero W with an official camera module though other Raspberry Pi versions will certainly work. I am using the official Zero case with camera lid as it makes a nice small package and protects the camera. I recommend using the Raspbian Stretch Lite Operating System. Ensure that you configure WiFi and have internet connectivity where you plan to position the Pi/Camera. You will need terminal or ssh access to the Pi during the setup described here.

Project steps:

  • Test camera and software configuration & prepare image for uploading
  • Setup SSH keys for easy, hands-off image file upload
  • Write shell script to take & upload image
  • Create a start-up service to launch the script & recover from errors
  • Create an environment where only RAM & not the SD Card is used
  • Prepare the target server & webpage to receive & update image
  • Enjoy!
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UPDATE: MongoDB 4.0.6 on ODROID C2 with Ubuntu 18.04

I use a MongoDB database to analyze data extracted from logs on Linux production servers that handle hundreds of thousands of users per day.  I also have databases that I use for research topics – oriented around K-12 education.  I have pulled data from The British Library and various datasets from the Europeana Collections.

I’ve blogged before on MongoDB running on a 4 ODROID C2 SBC Cluster with external SATA drives — see this post.  I had tried both Arch and Ubuntu flavors of Linux.  I pointed out then that MongoDB had an official Enterprise Server Version 3.6 for Ubuntu 16.04 ARM 64.  MongoDB Release 4.0.6 is now available for download (as of 15 February 2019).  Please check the license terms of the “Enterprise Server Version”.  There is also a “Community Server” version that might better meet your needs and/or avoid restrictions.  The Community Server install is what is described in this post.

OK it’s great that MongoDB has an official version for “Ubuntu 16.04 Linux 64-bit ARM 64.”  I, however, am running the latest Ubuntu OS for ODROID C2 – “Ubuntu 18.04.2 LTS (Bionic Beaver).”

OK, here is the quick and simple way to install the latest MongoDB on your ODROID C2 running Ubuntu 18.04…

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Replace that tennis ball with a talking Raspberry Pi!

The challenge is not to hit the ladder while parking

Our garage has a ladder sticking out near where we park our car.  We want to park close to the ladder leaving enough room to walk in front of the car and also allow room behind the car for the garage door to close. A typical solution to this need, and one we’ve used in the past, is to have a tennis ball on a string positioned such that the car window nudges the ball and shakes the string — so you know when to stop.  A great analog solution!  I, however, desired a digital solution that incorporates a Raspberry Pi.

This parking-assist solution doesn’t “speak” to me!

OK, a digital solution should either have a sensor that is tripped by the car or, even better, something that could dynamically measure and show the distance from the car to the ladder.  This would require some way to provide feedback to the driver.   Hmmmm, feedback could be visual or maybe via sound.  Yes,  that’s it!  I could have an R-Pi measure the distance and “talk” to the car driver.  Another project is born 😎

 

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MongoDB 3.0.14 for Raspbian Stretch

The main operating system for Raspberry Pi, Raspbian, continues to evolve.  The latest version as of August 2017 is “Raspbian Stretch” — based upon the current stable version of Debian 9.  The previous version was known as “Raspbian Jessie”.  One difference between versions is OpenSSL libraries. OpenSSL is a general purpose cryptography library that provides an open source implementation of the Secure Sockets Layer (SSL).  My previous builds of MongoDB relied on the older library.  As a result, my previous binaries for 3.0.14 and 3.0.9 do not run under Raspbian Stretch.  Given this change as well as other changes to MongoDB source and newer compilers, I could no longer compile MongoDB 3.0.14 with SSL.

After a few source tweaks and use of various compiler flags, I have manged to compile MongoDB core apps and tools.  These binaries do NOT support SSL and only run under Raspian Stretch on a Raspberry Pi 3.  [UPDATE — 2018 Mar 22] I have confirmed that these binaries work on the latest Raspberry Pi 3 Model B+ with the March 2018 version of Raspbian.

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PerAspera-AdAstra.Space

The Planetary SocietyMy wife, Claire, and I have been members of the Planetary Society since its founding in 1980. I was fortunate to be working at The Jet Propulsion Laboritory when Carl Sagen, Bruce Murray and Louis Friedman founded the society. Bill Nye, “The Science Guy” and space advocate, is now CEO.

The society’s mission has changed only slightly over the years and is now:

to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

So, why this post and why this title? The Planetary Society has offered a year-free domain registration with the Top-level domain (TLD) of “space” to members. Well, I needed to take advantage of that and spread the word about this TLD. Being a big Science Fiction fan, the phrase, “Per aspera ad astra” came to mind. Several variants have already been taken so I had to be a (tiny) bit creative.

Until I think of “better” content and have time to put something together, the URL, PerAspera-AdAstra.space points to this blog.

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MongoDB 3.0.14 binaries for Raspberry Pi 3

[UPDATE: 26 August 2017 – The binaries referenced in this post only work with Raspbian Jessie!  If you have upgraded to Raspbian Stretch on a R-Pi 3 or R-Pi 3B+, get the newer binaries]

The mongoDB documentation at mongodb.com states that 32-bit binaries are deprecated with release 3.2 and will be unavailable in future releases.  The latest version with 32-bit support (i.e. R-Pi with Raspbian) is 3.0.14 as of March, 2017.  I have compiled MongoDB 3.0.14 for Raspberry Pi 2 and 3.  I needed a few tweaks to the build process I used to compile 3.0.9 and associated tools. Use the installation instruction in my previous blog post to install and run MongoDB 3.0.14 on R-Pi.  The only change is to download newer files.  I have compiled MongoDB and Tools with the SSL flag — so the SSL option is available.

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Official MongoDB 3.4 on ODROID-C2 under Ubuntu

I’m a big fan of MongoDB but contrary to its “humongous” orientation, I like to think small as in ARM-based SBCs like the Raspberry Pi or ODROID-C2 and DBs under a terabyte 😉  You can get a lot of power out of tiny inexpensive computers and USB disk drives!  You can find my blog entries, below, for getting 32-bit MongoDB 3.0 working on R-Pi and 64-bit, MongoDB 3.2 working under ArchLinux ARM on ODROID-C2.

I had seen MongoDB community requests for a 64-bit ARM version and even a mention that there was “official experimental” development going on – including the efficient WiredTiger storage engine.  I recently perused the MongoDB Community Edition documentation for version 3.4 and saw a download option for “Ubuntu 16.04 Linux 64-bit ARM 64” on the MongoDB Download Center.  Ubuntu 16.04 is the default Linux supplied with the ODROID-C2 🙂  You can purchase a bare ODROID-C2 for US$40 at Hardkernel. Micro SD card or EMMC module with preinstalled Ubuntu Linux is extra.

Click more for installation instructions.

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CouchDB 2.0 on Raspberry Pi

The Apache Software Foundation has released CouchDB version 2.0.  CouchDB 2.0, is a “distributed” version of CouchDB, a mature NoSQL, document-oriented data-store that is accessable via a RESTful JSON API. Developers can take advantage of CouchDB’s offline capability and reliable data sync for web, mobile and IoT apps at (any) scale.

[NOTE: September 2017 — CouchDB 2.1 and Raspbian Stretch have been released.  Check out updated instructions in this blog post]

Current Raspbian (November 2016) can “apt-get install” version 1.4 and I have previously written about getting CouchDB 1.6 running on the R-Pi.  I have now installed version 2.0.0 on an R-Pi 3 and am sharing the process.  It is pretty straightforward to get CouchDB 2.0 running on the R-Pi. It takes a combination of the R-Pi specific 1.6 install and the “generic linux” 2.0 install to get things running.

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R-Pi Clock Radio – Zeroed!

clock_radio_20160909_smallWe had a really old alarm clock in our bedroom.  Really old.  The LED number segments, which were a nice dim red in color, had been dying at the rate of 1 segment a year and it was getting hard to read the time.  My wife finally had enough of my “I’ll get a new one real soon” excuse and bought a new big, bright, blue LED clock to replace the old clock.  It was blue … and *really* bright … even in its dim-mode 🙁  It had to go!

My converted 1942 Crosley Radio was collecting dust on my workbench.  I had finally received a Raspberry Pi Zero and Zero4U USB hub to play with but was already lusting after the new R-Pi Zero with camera port.  I recently upgraded the audio-output on my Mac from an old USB HiFiMan Express DAC to  a Schiit Modi DAC.   Hmmmmm, seemed like I had the ingredients to make a BIG clock “radio” with alarm(s) and great stereo audio?

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