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Workshop 88 at OSMOCES this month!
We are thrilled to be a part of the Open Source Mechatronics Outreach & Creative Exchange Symposium (OSMOCES) on October 13th at the IIT Rice campus in Wheaton. We’ll be there showing off some stuff we’ve been working on as well as running our introduction to Arduino workshop. See you there!
Shapeoko plots!
Our shapeoko has produced its first output under control of g-code! It’s taped up on the refrigerator at the space. 
Inkscape converted a bitmap of the logo to a .svg, the gcodetools extension generated g-code, and vi did the final modifications. The .svg needs a little cleanup, but it was more than adequate for this first test.
We now have a profile that’s calibrated to within a few percent for X, Y, and Z, though there’s still work on max speeds and accelerations. This plot was made with a ballpoint pen in a very crude holder. The bitmap-to-path converter generated inside and outside paths for the lines, so the mismatch of the actual plotted paths gives us some insight into opportunities for mechanical improvement of the shapeoko/penholder system. While the penholder is responsible for some of the tracking errors, we still have a lot to do to tighten up the shapeoko. The plate joining the Y and Z axes wobbles surprisingly. But it’s starting to work!
Update 10/2/12: Using the very convenient test facilities of the axis setup in linuxcnc’s stepconf tool, I maximized travel speed on all 3 axes. The shapeoko1 profile is getting pretty usable. Here’s a little real time clip of it plotting. This one used a Sharpie, and even though it only stayed in one spot while the Z axis raised or lowered the pen, the paper bled the ink into very noticeable dots every time it stopped.
New (well, old) Workshop Phone
I picked up an OBi100 adapter for the space a few weeks ago, and have been hunting around for a phone that we can use with it.
I stopped by the local Goodwill on my way in to the workshop one morning, and picked up two phones for $1.99 each. One was a Lucent speakerphone that was missing a power adapter (I managed to dig a compatible one out of our giant box of wall warts in the electronics room). The other was a fantastic old GE Model 500 rotary dial phone. One of our members with a bit of experience in the area pegged the year of manufacture as 1965, with the last service in 1984. I cleaned it up with some rubbing alcohol, and we swapped the old phone number placard for a W88 circuit board mask:
It took about 10 minutes of googling to find the pinout on the 4-prong adapter so we could hook it up, and it was hooked up to our Google Voice phone number and ringing.
The alligator clips aren’t a great solution, so I started designing a box to plug it into. I used OpenSCAD to do the design. The source files are available in my GitHub repo, but here’s a couple quick screenshots of the render:
I measured for the holes on the top using a pair of digital calipers, and then did some quick trig to figure out the offsets from the center point of the box.
The pins on the plug are arranged in a trapezoidal fashion so you can’t insert the plug backwards. The bottom of the box is set up so that I can drop in a Radio Shack perfboard with a standard phone line connected to a couple of spring contacts on the wider pair of the two holes. The standoff holes in the perfboard line up with the blocks in the corner of the box, and I have a second 3D model for the bottom of the box that sits below the perfboard.
The most difficult part of designing the box was getting the Workshop 88 logo to come out right. I found this great tutorial on how to use InkScape to build 3D shapes in OpenSCAD and I used the source image for the same circuit board mask that we stuck on the phone. Once I had that in place, it wasn’t too difficult to use it in OpenSCAD. Check out the GitHub repo for details.
I did a couple of test prints on the MakerBot to make sure everything fit together, and it looks like it is working pretty well. I haven’t done another print with the logo, but judging from the generated STL, it is going to be much more involved than the basic prints.
When I added the logos, the STL went from about 300K to over 2MB. I’m hoping that the print itself will be stable enough that the logo won’t lose resolution and look bad. We’ve got a new stepper motor extruder ordered for our MakerBot, so that may help a little bit with the resolution.
The next project is to get this puppy to dial out. We’ve had a few suggestions, from converting the pulse dial to DTMF using an Arduino Teensy to hooking up a Blue Box with an acoustic coupler. Right now the easiest way to use it is to dial out on a different phone, and then pick up the handset. That really isn’t all that much fun. I’m leaning towards the acoustic coupler method, but early experiments with DTMF generators on our cell phones didn’t go too well, so we may have a bit more work cut out for us. The Wikipedia article says that blue boxes no longer work due to changes in the switching infrastucture, which… ahem… anecdotal evidence would tend to confirm.
Shapeoko moves!
With the leads to its steppers extended, we’ve been able to get the Shapeoko to move in x, y, and z under manual jog control. Here’s a little clip. Next steps are calibration of all 3 axes and at least temporary mounting of the controller board.
Learn to Solder with the 2DKits crew!
Workshop 88 is thrilled to have 2DKits back to host a FREE learn to solder workshop with their blinkie kits. This workshop will be FREE and OPEN to the PUBLIC. Did we mention the event is FREE? You only need to pay for the cost of the materials in the kit. (Hey, if the materials were free, we’d give them away.)
Info from 2DKits:
What is Build-A-Blinkie and why are we doing this?
Our goal is to demystify electronic circuits. They are amazing pieces of technology that control vast areas of our lives. The complexity can be so great (take your cell phone for example) the technology is indistinguishable from magic. Well, we can do something about that! With building a blinkie, you get to build a circuit that does something interesting, with the satisfaction of doing it yourself. In the process we hope you gain an understanding of how they work, as well as a desire to learn more.
Never soldered before?
No problem – we provide as much or as little assistance as you require. We guarantee you will leave with a working blinkie. Thousands of kits have been built by folks of all skill levels in our workshops, and all will end up with a working blinkie.
We have easy-to-build blinkies for beginners that take minutes to assemble. We have blinkies of an intermediate skill level for those who have built them (or other electronic circuits before). And we have blinkies for those who desire both a challenge as well as an opportunity to build a work of art.
Lego Mindstorms Workshop 88 Class Followup
On Saturday August 25th, Jay held a NXT-G class at Workshop 88. He spent several weeks teaching kids at the Inzone program at Harper College, but this time he was teaching adults which is a very different experience! He quickly covered the basics of how each block works and how to use wires to pass data values around the program. He then explained how the programming can be applied to a sumo robot, and walked through the logic and the programming part-by-part to show how the settings affected the actions. There was even some of the Arduino code which he use with my NXshield to show how each command would look in a text based language in comparison to a graphical one. He also talked a little bit about NXC code for comparisons as well. After talking about programming and robots, the class started to discuss starting a FLL team. We are now seeing if we can get a FLL team together, and It is happening quickly! Jay been in involved in varying capacities with FLL for 10 years now. You can see his involvement here in this spreadsheet.
Workshop 88 3D printing information class!
You asked for it; we’re making it happen! On Saturday, September 8th at 1:00 pm in the afternoon, we will be hosting a class on how to use the 3D printer at Workshop 88. Are you just interested in seeing how 3D printers work? Stop by and check it out! As always, this class is OPEN TO THE PUBLIC. Questions? Email us: info@workshop88.com
The class will show how to go from some simple geometric description to a real printed object using workshop 88′s CupCake 3D printer. We’ll briefly describe using Sketchup to create a 3D model, then show how to convert to printable (.stl) format, compile to gcode, and print the object. We’ll show the parts of the printer, how to turn it on, how it’s controlled, and how to print an object. When class is done, you should feel fairly comfortable experimenting with the printer, and have an idea about what you can do with it.
Raspberry Pi thoughts
I got my Raspberry Pi (model B) in the mail a few weeks ago, and I’m just starting to dig into it. I ordered from Newark/Element 14, and got it in just under 2 weeks. They’re quoting quite a bit longer, so it was a bit quicker than I expected.
If you’re not familiar with the Pi, it is a $35 700MHz ARM processor with 100Mbps Ethernet, HDMI, composite video, 1/8″ audio, dual USB, SD card reader, and a number of 3.3V GPIO pins. There are several different Linux distributions available that run on the device. The model A is about $10 cheaper, and doesn’t have Ethernet.
I’m a Debian user from way back, so I was pretty happy that there was a Debian release for the Pi. I’m currently running on a 2GB SD card that I had lying around, but it is a fairly tight fit, so I’d suggest (and I believe they do as well) that you go with at least a 4GB card.
Out of the box, I was able to get the GUI running and run some basic applications. SSH access is also enabled, so I was able to hook the board up to my switch and access it over the network for package management and command-line tools.
I was extremely happy that the distro included native packages for ARM. I run DD-WRT on my switch at home, and the busybox packages are a bit limited for my taste.
I’m thinking about running Nagios on the board and breaking out the GPIO pins to show some Nagios metrics on a LCD screen or LED bar graphs. I’ve done LCD stuff with the Arduino, but having Linux on the board itself really gives me a lot of flexibility on generating the data to be output to the screen. I’ve been looking at the elinux wiki for reference on how to use the GPIO pins, but haven’t really done anything with it so far. I’m a bit nervous about interfacing directly because these boards are a bit pricier than Arduino boards, but the GPIO pins are supposed to be able to source 500mA, so that should be plenty for what I’m trying to do.
Love to hear your thoughts on what you’re planning on doing with your R. Pi in the comments!
Membership survey
We’re collecting some information from current and prospective members, and people in the community who might want to take classes at Workshop 88.
If you’re interested in becoming a member of Workshop 88, or just want us to know what kinds of classes you might be interested in taking, take a minute to fill out the survey!