Maker

OSEPP Arduino Starter Kit

Arduino and a Raspberry Pi 2BSo, a month or so ago, while traveling for work, I was bored in the hotel room and found out there was a Fry’s Electronics around the corner from the hotel. I decided to pop in and look around and see if I could find anything interesting. I also wanted to see how much Raspberry Pi 2B boards were there (and if they were comparable to Amazon.) They had a couple of Pis, a large selection of basic electronic components and a pretty decent selection of Arduino shields and parts.

I’d been looking into getting an Arduino for a while and decided what the hell. There may have been single packed Arduino boards but I really couldn’t tell from the cards which was the base board an which was just an add on shield. I ended up with the OSEPP Arduino Basic Starter Kit.  Honestly, since I hadn’t ever used an Arduino, I didn’t own an Arduino, and I had some basic but not super amazing electronics skills, this really was the best choice.

The kid includes a lot of nice basic parts as well as a guide book to get you started using these basic parts.  The box itself promotes the major projects of “Volt Meter”, “LED Game” and “Electronic Buzzer”.  It also runs through the basics of lighting up some LEDs.  The tutorials are decent though I wish there was a little more on the basics of how to work the bread board and the little wires.  It’s not hard to figure out, but it also isn’t super self explanatory if you didn’t have any experience with electronics at all.  the Volt meter tutorial is less exciting than hoped and the Buzzer just runs up the music scales but it could be modified to play a tune using the little piezo buzzer.

WP_20150630_09_21_48_ProThe LED game is neat, but simple.  You make the lights flash in sequence and you must press the button when the appropriate light is flashing, which causes the lights to flash faster.  There is also a 7 segment LED in the kid, which you make count down from 9 to 0.  This actually has a lot of fun potential and I have some ideas for it but I need to figure out how to light up both numbers to display a number (such as say, a temperature).

After exhausting the fun of the starter manual, on my next trip to the area, I bought a temperature and humidity sensor and wired it up.  This was a bit trickier since it required figuring out how to find and download the necessary libraries and modifying the code a bit to get it to read properly.  In the end, I managed to get things working though, which was kind of great since the AC in my hotel room didn’t have a digital read out, so I could know exactly how cold it was and why I was either freezing or sweating.

So, fast forward a bit more again, I’ve got some fun ambitions going and the idea of playing with several Arduino projects.  Unfortunately, while cheap, Arduino boards can add up to expensive.  Unless you buy cheap Chinese knockoffs for $3 apiece off of AliExpress.  I also have some cheap Network boards and temperature sensors coming.  Five boards total, five sensors and two network shields, for around $35, really isn’t too bad of a deal if it all works.

And thus, I have a ton of Arduino boards to play with now.

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Raspberry Pi Rack

Even before buying any Raspberry Pi computers, I had this sort of vision for neat rack to put several of them in. The idea evolved a bit as the logistics of it got ironed out but after picking up a second Pi (and planning to get a third), I went and built the thing.

Raspberry Pi Rack

Sorry for the mediocre pictures, I didn’t think to take photos until things were running and I didn’t really want to unplug it. It currently holds a Raspberry Pi B+ and a Raspberry Pi2 B, the B+ is running a ZNC server to keep me connected to several IRC channels and the Raspberry Pi 2B is running a small OpenSIM server, though I’ll probably re-purpose it since in testing performance seems to top out at around 2000 Prim cubes and 4 Avatars. The instance I’ve got running on my VPS is much more suitable. On the other hand, it could be a good place to “archive” builds.

Raspberry Pi Rack

The build itself is pretty straight forward. I used (roughly) the following materials picked up at Lowes:

  • 3 pieces of 10×8 plexiglass cut to 5×7 size.
  • 6 6″ #8 thread rods.
  • 8 (2 packages) of #8 rounded caps.
  • 3 packages of #8 nuts
  • 6″ Micro USB cables from Amazon
  • Cat 5 Cable cut and crimped as needed
  • 1 Netgear Switch I had already
  • 1 Choetech 40W Smart power from Amazon.
  • The smaller screws holding the Pis in are 4mm i believe, and it took two packages of them (16 screws and 32 nuts).

The hardest part was working with the Plexiglass pieces. I could have cut it with the Dremel but the edge would have been all crooked for sure. Instead I scored and snapped them, which did leave a jagged edge on one edge but it could easily be sanded off. On a starting note, the Plexiglass comes with a plastic protective layer, this should be left ON until final assembly to protect the clear surface as much as possible.

Anyway, to cut the sheets down, I used a square and a box cutter to but a line where I wanted the break to be on one side, then clamped the sheet down on the edge of the workbench between the surface and a 2×4. The 2×4 was mostly to help protect the surface of the plexiglass from the clamps. The cut edge should be on the up side, right at the edge of the surface and the 2×4 (or whatever) at the edge on top. The Plexiglass should snap more or less cleanly off. I had some small chips left hanging on the shorter 1″ breaks to shorten the shelves to 7″ from 8″. I used a small hammer while the pieces was still clamped down to chip these down a bit.

The real trick was drilling the holes. In the end, I found the best results came from clamping all of the plastic sheets together between some boards and drilling them all at once. There should be a piece of wood completely covering the bottom of the drilling spot to help support the plexiglass as the drill penetrates through.

I had some trial and error trying to drill my sheets separately, so the holes are not perfect. For the mounting holes I laid the Pi itself where I wanted it and uses a pen to mark the holes. I probably could have done a bit better with a paper guide though.

Assembly was pretty easy, just a lot of tedious screwing of nuts as the thread rods were fed through the holes. Each shelf takes at a minimum, one nut above and below to hold them in place and the rounded caps go on the top and bottom. The power supply and switch are not mounted, they are simply sandwiched in place between the shelves, though the supporting long bars were positioned around the Switch to prevent it from sliding left or right or backwards.

The Power supply I picked because it has two standard wall outlets on one side. I used the Dremel to cut holes in the top sheet to allow these plugs to be accessible. I wanted the unit to be as self contained as possible, these plugs give me a place to plug the Switch in. It’s important when choosing a power supply that it has enough power on all ports to power a Pi. A USB HUB doesn’t work since it will distribute power across all the ports. Several ports I looked at had 2 “high output” ports for iPads and iPhones but the rest were lower output.

The USB power cables were 6″ jumpers I found on Amazon and the CAT 5 cable were small jumpers I made myself with ends and a crimper. When I add the back two Pis I’ll need different cables though, likely cables with a 90 degree connector and definitely longer ones.

Raspberry Pi Rack

The whole package sits nicely on top of my desktop box next to my Synology NAS.

Building up to the Raspberry Pi

Raspberry_Pi_LogoI’ve been hitting the Raspberry Pi and Arduino pretty hard lately.  I plan to detail my projects some here in the future but I figured it would be good to start off with a little “why” and a little history.  I mentioned the Arduino, but I only plan on touching on the Raspberry Pi here today.

I’ve used a secondary PC for projects for a very long time now.  A second or third or even fourth PC an be extremely useful for learning more about PCs.  The main nicety is that if you want to completely wipe it out, you don’t have to worry about what to do with your important data on your main PC.  Want to try a new Linux distro?  Screwed up some configuration?  Just reformat and try again.  You can do some of this with Virtual Machines but that can mean sharing resources which isn’t always a good solution.  Also for any long term “always on” projects like a web server, having a dedicated box is generally cleaner and more secure.

The first project PC I had was my first personal PC that wasn’t “the family machine”.  When I graduated from High School, I was given a PC of my own. It was at the time a pretty “top of the line” Pentium 2 IBM with a blazing 450mhz processor.  Over the years i upgraded the hard drives and RAM and eventually the motherboard and processor.  Eventually, I found that I had a box containing all of the parts from the original machine, so I rebuilt that machine, installed Redhat Linux on it and started playing around with web server software.

During my time working IT/Engineering at my old television job, I accumulated several project machines.  When computers were upgraded, we just sort of let the old machines pile up in the back.  Sometimes these machines would go to employees if they needed a computer.  Sometimes I’d do projects at work to streamline the processes and we’d use a machine for some sort of ftp or scripted copy project.  If they were too old or just broken they’d get recycled.  I ended up with several of these machines as well.

The problem with these project machines is they are full PCs.  They need a lot of power to run, especially for something that is a very low use webserver or game server.  They also take up a lot of space.  Also, since many of the machines were used and old, they were prone to failure.  I started replacing the towers with old laptops but these have their own issues.  They take up less space and use marginally less power, but they also tend to over heat in confined spaces and if a laptop had been replaced at work, it likely had a severe issue and thus these laptops were more prone to failure and less easily repaired than the towers.

These days I’ve been phasing out the bulky old machines for Raspberry Pis.

The Pi uses way less power than a whole machine.  They are also super cheap, so buying several of them over time doesn’t really break the bank.  They aren’t super powerful, but I really don’t do anything that requires a ton of processing power, and because they are cheap, I can use several of them running single tasks to spread the load.  Frankly, they are still better than some of the towers I’ve used in the past spec wise.

So why the Pi?

There are a lot of options out in the micro PC space.  The Raspberry Pi is probably not “the best” but it’s definitely the “most supported”.  I like to learn and play around with new technology, but I’m at a point where I’m not super keen on having to fight with obscure technology.  This is pretty much the why of the Pi.  It just works.  Or at least, I can generally Google how to work it.

The Pi also runs Debian based Linux, which I am most familiar with when it comes to Linux.  Since the Pi is a full computer, it’s great for software projects.  There are GPOI pins but I’ve not really explored them yet.  I’m leaving the hardware tinkering to the Arduino for now.

Roll Your Own OpenSIM with Digital Ocean

os_doOk, so starting off, there was a bit of trial and error involved here and a bit of backtracking.  I’ve done what I think is a good job of backtracking through my steps though to get all of the actual steps listed.  TWO!  I’m not going to vouch for this being 100% accurate anytime after posting.  My experience with OpenSIM is that every damn time seems to be completely different for SOME reason.  That said, it should still be mostly a good guide.

For the uninitiated, OpenSIM is basically an Open source, user controlled Second Life server instance.  It can be connected to other sims via the hypergrid protocols.  This guide does not cover anything involving Hypergrid or connecting to other grids.  It is for creating a private accessible from anywhere OpenSIM instance using Diva on Digital Ocean.  Diva is a pre configured OpenSIM stack deal and Digital Ocean is a Virtual Private Server (VPS) host.

The rest of this post is behind a cut…

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Raspberry Pi Project 01 – Web Server

Raspberry-Pi-Logo So, just as a start, this isn’t a how to of any kind.  There are already plenty of tutorials on how to do whatever with the raspberry Pi.  Unless I’m pushing something unique, I don’t feel the need to provide another explanation of how to do the same thing a hundred other people have done.

I completed my first trial project on my Raspberry Pi of setting up a web server.  This is a pretty simple process that I have done dozens of times before on Ubuntu and Windows so it isn’t exactly an amazing feat.  The most amazing part is that I followed through on it instead of putting the Pi aside for “someday” like so many other projects.

The set up is really straight forward.

sudo apt-get install apache2

sudo apt-get install php

sudo apt-get install mysql

wget wordpress from wherever

sudo apt-get install vsftp

sudo mysql

create database wordpress

Futz with some permissions…

That’s it, pretty much the same as Ubuntu.  I guess this is a hot to after all.  I followed up by setting up WordPress through the WordPress interface.  I added a theme and some plug ins and created a few dummy posts.  Mostly I wanted to gage performance.  Granted, a single user web server sitting inside a firewall on a LAN is probably not the best way to gage functionality.

Everything ran fine though.  FTP uploads were a little slow, but I imagine part of that can be attributed to the memory card access speeds.  It wasn’t unbearably or unusably slow.

The main issue is that, I already run a private web server on a full blown machine inside my house.  It’s useful for playing with web dev stuff, I run a WordPress instance archiving all of my posts online together, I host a couple of other web apps for things like my webcams and Twitter analytics.  It is already running and does more than the Pi is probably capable of doing all at once.

Using my Pi as a single WordPress host is a waste of a good Pi.  It was a nice exercise to get familiar with the mechanics of the Pi, but it’s not really all that useful long term.  So I’ve wiped it out to move on to a new project.

I’ve been debating on what to use it for on my second Project.  I have been flip flopping between an XBMC media player and running Retro Pi to make it into an emulation station.  My main hang ups, the media player won’t be super useful without a media server to back it up.  I plan to buy a NAS later this year and start ripping all of my DVDs to it but that’s months off.  Retro Pi seems like the logical choice then except I have an old Netbook with a busted screen I plan to use to for building a retro arcade machine.  Still, it might be good to compare the Pi to the Netbook for the emulation station.  Also, I have more than one room so I could use two emulation boxes pretty easily.  I thought about using the Netbook guns to build a Stepmania/DDR box anyway, and it’s probably better suited to run Stepmania than the Pi is anyway.

Anyway, as usual, lots of ideas, lots of plans, maybe something fun will come out of it.