Year of the Maker: Week Eleven in Review – Thoughts on Rapid Prototyping

I bought a great car a few months ago, but it is *not* a new car. It’s a 2005 Porsche Boxster S and is a profound pleasure to drive. I’d much rather buy a great used car than a new car that I wouldn’t love. One down side to buying a car from the middle of the previous decade, though, is that it lacks some of the more modern electronics. In my case, I have to toss my iPhone in the passenger seat and connect it to the radio via an FM transmitter (there’s no aux input jack). The phone slides around all over the place in the passenger seat becuase there’s no good place to attach a holder on the dash. Honestly, though, I could go without music entirely if I had to because the driving experience is superlative.

Given a choice, though, I won’t go without my music, and as a maker I don’t have to!  Since this a wonderful car, I want an iPhone mount that won’t take away from the car’s appearance.  Fortunately, there is a conveniently-placed ashtray (and I don’t smoke!).  Unfortunately, it’s too small to simply drop my phone into it (and I couldn’t press skip/pause/replay if it did fit).  However, that ashtray can serve as perfect location for an iPhone mount if such a thing existed.

That’s where rapid prototyping comes in to play along with 3D-print-on-demand that’s available to me as a builder of a 3D printer.  First I made a few quick measurements of the ashtray and the phone (in its case).  I then did rough designs for the mount and the bracket.  Save and print and I have “rough sketch” real objects.  No surprise to me that they wouldn’t fit/work — I didn’t expect the sketches to be the final product.  What this rapid “idea to model to object” process does is let me quickly and easily determine what changes I need to make.  It didn’t have to be perfect from the start.  In this case, the grip for the phone was too thin, the ashtray turned out to be smaller on the bottom than the top and the slot for the grip was too shallow.  I ran through a few more iterations before getting it exactly as I wanted.  You can see the progressive changes here:

Rapid prototyping (model –> build –> repeat) is a fantastic real-world equivalent to the agile programming methodology.  It’s also a lot more fun than having to get everything right on the first go.  Once I was satisfied I had exactly what I wanted, I changed out the filament feeding into my printer from white to sky blue to make it prettier.  The final product is two pieces that come apart so that I can store the grip in the center console and close the ashtray when I’m not using it — this keeps the original design of the car’s interior intact.  Here’s the final version:

I may purchase a spool of grey plastic in the future and reprint it so that it matches the grey interior.  In the meantime, though, I now have a custom-made, rapidly-prototyped secure mount for my iPhone that’s a perfect fit for the ashtray in a 2005 Boxster!

Year of the Maker: Week Ten in Review

Yeah, yeah… I’m late posting again. You get a full refund of all the money I made off your viewing of my blog up to today (3/16/12).  🙂

The biggest progress I made was on linear bearings:

My old version and my new…

The longer version on the right is the new one. Being longer, it has much less play than the shorter, old version. However, it also produces LESS friction. What’s the secret sauce? The “teeth” you can see that touch the rod taper away along the inside of the bearing so that the only touch near the ends where they are needed. Negligible play, low friction: best of both worlds!

The other cool aspect of this design is that you cannot make these parts via a mold — they require a 3D printer to create if you want to make them out of a single piece. Traditional manufacturing processes would find this design to be problematic to say the least.

I’m hoping to have Week Eleven up in a timely fashion — with a nice bit of SketchUp + 3D printing in the works!

Year of the Maker: Week Nine in Review

Yep… didn’t get last week’s update up. Better late than never! Not much to say about it, though. I worked on creating linear bearings (picture below) and found that I need to add a LOT more infill for that design to work properly. In the process I decided to upgrade my 3D printer’s software — which in turn requires firmware upgrades which in turn proved difficult. Hopefully I’ll have the new firmware/software up-to-date this weekend.

Year of the Maker: Week Eight in Review

Yay!  This week was productive! More experiments with Sketchup and my 3D printer:  printable universal joints (click that link if you don’t know what a Universal Joint is — the animation will make it clear).  There are a LOT of ways to create a universal joint, but this is my own design (version 0.1) working under the constraint that it had to be printable (and that’s a big constraint that I won’t go into here).   Here is the result:

I did this for a couple of reasons.  First, I wanted the challenge of making this beast with NO screws, bolts or nuts.  It’s strictly snap-together and can sustain very large forces acting on it (which means it was really, really hard to put together!).  Also, u-joints + wire + servos + arduinos = animatronics!  This will end up in either a cool robot or costume.  It can be used in robotic tentacle-type grips or robotic tails.

For those of you that might not know what 3D printing is all about, here’s a 30 second video of the my “Kevbot 3000” printer in action.  The universal joint took over two hours to print in total, so this really is just a tiny sample:

3D printers like mine melt a plastic filament (a whole lot like what you feed into a weed-eater) and extrude it layer by layer into whatever shape you want.  We really are living in the future for anyone that wants to expend the time and energy to get there!

Review: Full Spectrum Engineering 40W Hobby Laser (Deluxe Model)

Around the end of February I ordered a 40W “Hobby Laser” from Full Spectrum Engineering.  Other lasers such as those offered by Epilog were simply way out of my price range.  If I had a business built around a laser I might have sprung for one, but for a personal tool that was out of the question.  However, I did really want a laser.

Unboxing the Laser

Unboxing the Laser

After much research I settled on Full Spectrum which arrived a couple of weeks ago.  Now that I’ve had time to get it up and running and actually have some knowledge of it, I thought it time for an initial review.

What I ordered: No need to write out the parts list here when you can see for yourself!

Fancy bits?

The closest thing to a bell or whistle only comes with the Deluxe Model:  a USB interface and printer driver software.  Otherwise…  the stage can be raised and lowered to focus the laser via a bolt that sticks out the bottom of the case (and which is hard to reach and turn).  The laser output is monitored by a simple analog ammeter and controller by a knob with no markings except to indicate that clockwise is “more power” and counter-clockwise is “less power”.  It’s a big, sturdy enclosure with lots of open space around simple, get-the-job-done components.  None of these things are drawbacks to me — I’ll explain why shortly.


Like any tool of this sort, it takes calibration, experimentation and a bit of fiddling to get good results.  Laser cutters are NOT laser printers!  If all you want to do is etch a few pictures onto a few items then, yes, you can get up to speed very quickly.  However, if you really want to use a laser as a tool for precision cutting you have to know what you’re doing.  This machine will not hold your hand through the process any more than any machine shop tool would.  Don’t buy it if you think otherwise!

The Big Plusses

I previously mentioned that the lack of bells and whistles and the big open spaces weren’t downsides to me.  The lack of fancy bits means it is affordable and easily maintained by me.  This isn’t a machine that requires regular visits from a vendor service tech.  The simple design and lots of space also mean that the system is HACKABLE.  What do I mean by that?  I mean that it is going to be extremely easy to upgrade this machine with features that I want.  Things like a stepper motor to adjust the build platform height, an Arduino power monitor/controller for the laser power, a flow detector for the cooling water (it doesn’t tell you if you forgot to turn on the cooling pump!), etc.


Well, the exhaust fan died after a few days, but that was because the manufacturer didn’t tie a knot in the power cord inside the fan.  That resulted in fatigue where the wire was screwed in to the terminal and the wire broke.  I fixed the break and reinstalled the wire WITH a knot to keep it from breaking again.  Also, the air assist compressor stopped working while I was setting up and calibrating.  It had been humming away for a hour or more and apparently overheated.  I turned it off for about 15 minutes and it has been fine ever since.  The lack of a beam combiner (an optional upgrade) does mean that the red dot pointer is an approximation of where the laser will actually strike.  Finally, the big rim on the honeycomb table cuts down your cutting area quite a bit — you lose a good 1.5  to 2 inches in each direction.  Finally, my z-platform is not quite leveled properly, so I need to remove the belt and tweak that (not a problem in most cases, but cutting larger objects in 1/4-inch acrylic needs accuracy).


The Full Spectrum Engineering Laser is *exactly* right for me.  I’ll upgrade the basic bits to suit my desires along the way.  I’ve already cut a 1/4-inch acrylic z-stage for my Makerbot (took some time to get it dialed in just right, but I figured it out).  I’ve also had good luck with 0.002-inch Kapton film for use in printed circuit board solder stencils.  Etching is, of course, even easier and is giving me good results as well.  The laser does a great job, but I wouldn’t recommend it if you were looking to do custom laser cutting/engraving as a commercial enterprise.  I think it’s up to the job, mind you (at least the actual laser itself), but a more expensive laser will save you a little when you are swapping materials in and out all day long by offering a few more bells and whistles.  Also, the air exhaust and compressor are a bit more entry-level than I would want to run for 8 hours a day.  Of course, Full Spectrum states clearly in the name that this is a 40W hobby laser, so that’s not a real criticism either.  Overall I am very satisfied and won’t hesitate to recommend it to other makers/hackers/hobbyists looking to add a laser cutter to their tool set.

Perfect Ubuntu: Optimizing Your Browser with a RAM Disk

Every time I install Ubuntu Linux on a new computer I realize that I’ve forgotten how to do a bunch of configuration stuff that makes my computer experience so much more pleasant. To fix that, I’m starting a series of blog entries to document the tweaks (all to be tagged with “perfectUbuntu”. Here’s the first: optimizing Chrome, Chromium, and/or Firefox on Ubuntu Linux by using a RAM disk for its cache.  These instructions are for a single-user system.  If you have multiple users you’ll need to modify this a bit if you want it to work for each of your users, but if you’re running a multi-user installation you probably know enough to handle that without difficulty.

Applies to:  Ubuntu 10.10 (10.04 seems to need to use the “ramdisk” command in /etc/fstab instead).

First, make sure you want to do this. Do you have RAM to spare? I’m currently running on a 4GB system, so even when I run the occasional virtual machine I have plenty to set aside as a half-gig RAM disk. Also these instructions apply only to newer versions of Ubuntu (those running Grub 2). Open up a terminal and dive in:

1) Most of our commands require superuser privileges, so we might as well just switch to root.

sudo su –

2) Edit your startup script:

nano /etc/rc.local

Right above “exit 0” we’ll add the commands that need to run each time at startup:

mkdir /tmp/ram

mount -t tmpfs -o size=512M,mode=750 tmpfs /tmp/ram/

chown -R yourUserName /tmp/ram/ (replace “yourUserName” with your user name)

Save the changes and exit (ctrl-o, ctrl-x).

3) Edit your boot configuration:

nano /etc/default/grub

Change the GRUB_CMDLINE_LINUX line to read:


and again save and exit.

4) Reboot and verify that /tmp/ram now exists with “drwxr-x—” rights with you as the owner.

5) Relocate your existing browser (no need to do this as root) cache and link to it:

For Chromium:

rm -rf  ~/.cache/chromium

ln -s /tmp/ram ~/.cache/chromium

For Google Chrome:

rm -rf  ~/.cache/google-chrome/

ln -s /tmp/ram ~/.cache/google-chrome

For Mozilla Firefox:

The cache for Firefox can be found inside your Firefox profile (which includes a big random string in it). As long as you only have one Firefox profile you can do this:

cd ~/.mozilla/firefox/*default

rm -rf Cache

ln -s /tmp/ram Cache

That’s it!  Restart your browser and you should notice a nice bump in speed as your browser no longer writes cached files to disk but keeps them in your RAM disk.  Much faster.  As an added bonus, your cache will clear at every reboot.

Why I’m Buying an iPad

This is about my personal reasons for buying an iPad. I think they are going to sell a gazillion of them, but for many different reasons. I’m not covering all the reasons I think the iPad’s time has come. I’m only covering why its time has come for me.

This is my current computing environment:

  • a desktop (Ubuntu Linux on an AMD-powered HP Pavilion with a 20-inch screen).
  • a Lenovo ThinkPad T500 (Windows 7/Ubuntu dual boot from my employer)
  • a 3G 16GB iPhone

My favorite environment to work in is Linux (in spite of how poorly it handles Flash video at times).

Each has its pros and cons.

The desktop is a great work environment for coding, word processing, home server functionality, media storage, etc, etc, etc. However, to use it I have to go to the room it’s in, sit down at a desk and stay there until I’m done.

The laptop is OK for coding, casual surfing, email, word processing, etc. Its plus is portability, but it is not always on nor is it really all that portable, nor is it comfortable to use, nor is it big enough to put coding and output windows up simultaneously. In other words, it does about everything I need (except server functions), but does them poorly. Because of that, I mostly use it at work as a second system when I need to do testing and debugging.

My iPhone is great when I’m on the go. Connection anywhere! I use it a lot at home as well because it can always be near me, doesn’t have to be put to sleep to conserve power, and is therefore great for looking up a quick fact or checking for an important message. However, for anything substantial (even reading articles at the Times or Wikipedia), the tiny screen and dinky keyboard are not sufficient.

Then comes the iPad. It’s small enough to be wherever I am in the house, but big enough to use comfortably for reading articles, checking email, social networking, reading eBooks, etc. In fact, it’s big enough to do light duty as a word processor, blogging tool, and even for Remote Desktop to the office or Secure Shell into a server. For pulling up schematics when I’m working on a project it’s big enough to see clearly, small enough to stay out of my way. It also sports a plethora of casual (and some not-so-casual) games for a few minutes of downtime. In other words, I expect my iPad to become my primary computing device for non-work activities and an important secondary device for work activities.

What’s the big loser as I see it? The ThinkPad. Many people see the iPad as a fourth class of device and are asking “Why?” because we already have smartphones, laptops and desktops. The trick for me is to imagine having two devices: a smartphone and a desktop. If someone was to introduce a third device, would you rather have an iPad or a laptop? There are PLENTY of people that will say “laptop” or “netbook” or the like, but for ME, that third device would be a Star Trek-like pad that does all the casual things I want to do and does them well. For big jobs I’d have my desktop. For extreme portability, my phone. I can’t imagine (personally) choosing a laptop over an iPad as the sweet spot between desktop and smartphone.

Update: Work, work, snow and SHOPBOT

Wow, but I’ve been busy…

We went to the mountains over the weekend (which was fun but more tiring than restful). Sunday we had to beat it back home as fast as possible before the coming late-winter storm. Even with that we barely made it down the mountain before the roads became too treacherous to travel.

Schools were closed Monday due to the snow, but we had an engineer coming in to help install our new data storage system (IBM N-Series 3300), so I had to be in at 8:00 anyway. That took all day Monday and much of Tuesday (and that’s just the installation work — there’s then a ton of work for me).

Last night, though, I got to take the ShopBot SBU (safety and basic usage) course at TechShop. Fortunately, they included a how-to and safety manual. I see to have trouble really learning things if I don’t read them. Too bad I didn’t have the text BEFORE the class.

In any case, it’s a fabulous machine — I can’t wait to use it for real!

Flu Bugs and Arduino Instructables

In my previous post I mentioned fighting a winter bug.  Looks like it’s a flu bug.  Great…  The good news is that I did get a flu shot and think it has kept it shorter and milder.  I hope to be back at work tomorrow. I don’t like taking sick days, and they always leave me restless and eager to get back to work.  I can only stomach TV in small doses.

As I improved a bit I finished writing up my Arduino tutorial for Instructables.  My first instructable! Warning to friends and family that might wish to check it out — it’s pretty technical (not that I expect you can’t follow it — just that if you don’t own an Arduino you won’t want to!).

The tutorial takes you from an out-of-the-box Arduino board all the way through building a working Arduino project with the necessary programming.  Anyone actually going through the whole thing would probably need to set aside a couple of hours.

In any case, I learned a lot by creating it and now get the chance to pass it on.  🙂

UPDATE:  Instructables bumped my tutorial to first page featured article status!  I’m ridiculously honored!

It Came!

My Arduino…


Before long I’ll be making myself into Iron Man!

OK — in case you didn’t know, the Arduino board allows for a variety of analog and digital inputs and outputs and features a programmable controller to act upon the signals it receives.  The chip is programmable via a built-in USB port with a FREE programming kit available from the makers.  Very cool.  You can build unbelievable intelligent devices with this very inexpensively.  Mine ran only $34 (including shipping) from Adafruit Industries.  The owner, Lady Ada, also features significant tutorials on her website devoted to getting started with the Arduino.