Archive for the ‘Projects’Category

CNC Build Club – 4 Axis Milling

4th-axis_large

 

(picture from CNCCookbook blog)

This week we are going to play with the rotary axis on the little CNC mill.  We are going to assemble it and calibrate it.  We will use a demo of DeskProto to run a job on it.  We will of course start with the CNC Ninja Squirrel, then try some other projects.  It you have something cool to try, bring a file in STL format and a round piece of material to mill it out of.

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Join us Thursday Nov, 14th at 7:00pm.

 

13

11 2013

A 3D Printed Pinhole Camera

It started simply. On October 3rd, I tabbed over to XChat and saw a highlight waiting for me:

<NegativeK> loans: http://www.thingiverse.com/thing:143882

Clicking the link took me to a Thingiverse page for a pinhole camera.

<loans> NegativeK: why am I not printing that right now

<NegativeK> Print that camera, loans, and I’ll share some dev kit and chemistry

So it started. Over the next week or so I spent some amount of time in front of the Lulzbot, coaxing the camera into existence. The prints all went fairly well, with no catastrophic issues. I had to print a body, a filmholder carrier, tripod mounts and shutter parts, and a ‘lens’ tube. I’d estimate it was less than 10 hours of printing, all told. I assembled the camera using with ABS slurry and fasteners, only needing to do a little bit of touch-up here and there to get everything fitted. I tested for light-tightness in a dark room with an LED flashlight. I made a pinhole out of some aluminum cut from a soda can. I took a stab at the ‘dimple and sand’ technique, though I think it’s something that will take some practice.

PINH5AD and shutter parts

The body/lens combo, shutter parts and tripod mount.

Shutter assembly

The completed shutter assembly.

Now I had a mostly-finished camera. The last ingredient was to be some adhesive-backed velvet, which would act as the gasket material. Someone (Everett), however, couldn’t wait. So on Sunday the 13th, we loaded up some film holders and cobbled something together in true hackerspace fashion.

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Don’t judge me. Then we carried the mess out into the alley, because we wanted to minimize exposure time. We set up to take a picture of our rollup door, because what else is out there?

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Metering was accomplished with a DSLR and a piece of scratch paper. This camera’s ‘lens’ is f/225 and the film was ISO400. We calculated a 12 second exposure time. We double checked everything, pulled the dark slide out, prepared a timer on a cell phone. Then we hit go and opened the shutter. Twelve long seconds went by, I was sure I was ruining the photo by shaking the camera  with the hand that was operating the shutter. Then the phone beeped, the shutter closed, and we were done.

Not being the sort to waste time, we quickly moved into the processing phase. I haven’t developed film since a high school photography class, but Everett was ready to go. It went down at the shop sink (In the newly cleared hot metals area), and soon enough we had our exposure. The negative looked good. Surprisingly good. Scanned with a DSLR, we had our photo:

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It isn’t perfect, but it’s a result. It’s even a reasonably well-exposed result, considering. The camera will benefit from a more precisely manufactured pinhole.

Our next goal is to try some exposures on positive paper, which is a process that gives you a print directly. The downside (maybe not?) is that it will be an hours-long exposure. We’ll see how it turns out.

 Until next time, hackers. -Derek

20

10 2013

Raising the BAR

New Bar Front ViewIt all began with a dream: a cerebral lubrication station worthy of our fine hackerspace, serving as focal point to transform the lounge from a seldom used area into PS:One’s central communal nexus. From there, a collaborative project was born. PS:One member Greg Daneau built the first incarnation of our bar. He built the bar top from an unfinished door, an open frame supported it, and it had a foot rail made of pipe. The result was impressive, even if it was but a small shadow of the glory that the bar ultimately became. Thus began an asynchronous collaborative project, with hacker inspiring hacker to hack the bar to higher pinnacles of zymurgical greatness. And it arguably served as an “altar” for the budding Beer Church.

Kegerator InteriorSeeing the bar in all its inebriating glory inspired member Ryan Pierce to build a draft system and kegerator from a donated refrigerator. It can hold up to six 5-gallon Cornelius kegs (used frequently by homebrewers) or a single 15.5-gallon beer keg. A fan forces cold air through an insulated hose carrying the beverage lines to the draft tower. The draft tower itself was built from PVC pipe, fittings, and drain flanges. An insulated return hose carries the air back to the refrigerator. This air loop keeps the beverage lines and taps cold, which reduces the tendency of beer to foam in the line. Jeremy used our TIG welder to weld a drain pipe to a stainless steel drip tray, directing any spills into a bucket.

The existence of the bar and draft system steered the focus of Beer Church towards kegging. Cornelius kegs can hold finished beer and can be used for natural carbonation (caused by additional secondary fermentation from priming sugar) or forced carbonation supplied directly from a CO2 tank.

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04

09 2013

SEM, EDX and fun with liquid nitrogen

Our scanning electron microscope came with an Oxford Isis EDX detector that we were told was non-functional. After a little poking around, I discovered that the replacement power supply which supposedly didn’t work was shipped from London, where the default power is 240V. After changing the voltage, the computer suddenly recognized the electronics, and it passed all the self tests. That looked like a good sign, so the next step was to acquire liquid nitrogen, which is needed to cool the detector.

Fortunately, one of our members owns NFC, a company that, among other things, sells liquid nitrogen. He loaned us a dewar of LN2 so we could test it out. After transporting it back to the space, I asked Everett to watch from a safe distance and let me know if anything was spilling while I filled the dewar attached to the SEM. He took some video of the process. The plastic funnel I used was cracking as I was pouring, which in hindsight wasn’t that great of an idea, so maybe we need to find another solution here….

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The detector took over an hour to cool down, but ultimately it worked beautifully! I kicked up the energy of the electron beam to 20 keV which excited the atoms in the sample to give off characteristic X-rays. The EDX unit measured the energy spectrum of the X-rays given off, and was able to suggest possible elements that have those peaks, which I could then label. The next day Susan Young, the microscopist who used this SEM when it was at its former home, came to the space to give me some advice on the EDX and the sputter coater.

At center is an aluminum sample stub, with a square of copper tape and a strip of carbon tape. The SEM is imaging an area showing all three surfaces.

At center is an aluminum sample stub, with a square of copper tape and a strip of carbon tape. The SEM is imaging an area showing all three surfaces.

After calibrating the detector on a copper target, I then tried imaging a sample that consists of an aluminum sample stub, copper foil, and carbon tape, that has some of each of these exposed. I’ve labeled three peaks for copper, one for aluminum, one for carbon, and one for oxygen. The peak at 0 is just an artifact of the detector. Here is a movie of the X-ray peaks building as the detector collects data:

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Here is the complete spectrum:

EDXSpectrum

The EDX detector has the ability to determine not just what is in a sample, but where it occurs in the sample. I did this by defining energy windows, above. One for carbon, one for one of the copper peaks, and one for aluminum. Each time the EDX detects an X-ray whose energy falls within one of the bands, the EDX sends a pulse on one of several channels to the SEM. The SEM operates in X-ray mapping mode and, because it knows the beam’s position when the pulse is received, it makes a dot on a color coded map showing where that element occurs. This map is an overlay on the secondary electron image of the sample.

EDXMap

The aluminum peak is colored cyan, which dominates the upper left part of the sample. Magenta corresponds to the copper peak, which appears primarily on the lower left. Orange represents carbon. The detector didn’t detect that much of the carbon peak (seeing as it’s the smallest of the three), but orange dots are clearly visible on the right hand side. The surface in the middle is the edge of the copper tape, but it is almost vertical relative to the electron beam, so it doesn’t seem to be giving off many X-rays.

All in all, this is seriously cool technology.

21

07 2013

NERP Tonight: QT and Steppers

NERP Tonight: QT and Steppers

 

Tonight at NERP, we’ll have a show and tell about the PS:1 entry in the Element14 hackerspace challenge.(http://www.element14.com/community/community/knode/single-board_computers/next-gen_beaglebone/blog/2013/06/12/beaglebone-black–the-2013-hackerspace-challenge/)We’ll highlight use of the QT framework and gui tools on the Beagle Bone Black to run the stepper motors on the pick and place machine. There are always challenges in getting a new platform up. One challenge has been resolving version problems with the QT3 to QT4 transition on ARM. We’ll find out how that’s going. Also we’ll also have a tour of the system’s Z- and θ- axes mechanism and find out what the test results were on using some very small stepper motors to drive the head. As a bit of improvisational comedy, some of the tests will be done live during NERP! Yow!

NERP is not exclusively raspberry pi, the small computer interest group at Pumping Station:One in Chicago.

 

Find NERP and Pumping Station:One
at http://www.meetup.com/NERP-Not-Exclusively-Raspberry-Pi/
and http://pumpingstationone.org/

NERP meets at 7pm 7-15-13 at Pumping Station:One, 3519 N. Elston Ave. in Chicago.
Doors open at 6:30pm. NERP is free and open to the public.
Ed Bennett ed @ kinetics and electronics com

 

Tags: electronics, embedded, NERP, Open Source, raspberry pi, hackerspace, Beagle Bone, Element14

 

 

15

07 2013

Programming in Erlang -plus- Making an Xbox Media Center on the Raspberry Pi

Tonight at NERP, we’ll have two presentations.

Brian Chamberlan will tell us about using Erlang to program/control the RaspberryPI/BeagleBone. Erlang is a functional, general-purpose concurrent, programming language and runtime system. Erlang provides language-level features for creating and managing processes with the aim of simplifying concurrent programming. Processes communicate using message passing instead of shared variables, which removes the need for locks. [paraphrased from wikipedia]

Michael Beck will show us how to set up Xbox Media Center, XBMC on the Raspberry Pi. Pretty much every possible mode of interacting with a digital media stream is supported by XBMC. The Raspberry Pi’s excellent (but proprietary) video rendering hardware makes it an ideal platform for building a home media center.

NERP is not exclusively raspberry pi, the small computer interest group atPumping Station:One in Chicago.

Find NERP and Pumping Station:One
at http://www.meetup.com/NERP-Not-Exclusively-Raspberry-Pi/
and http://pumpingstationone.org/

NERP meets at 7pm 6-17-13 at Pumping Station:One, 3519 N. Elston Ave. in Chicago.
Doors open at 6:30pm. NERP is free and open to the public.
Ed Bennett ed @ kinetics and electronics com

17

06 2013

CNC Gonzo Build #2 – Recap

ps1_draw

The project was to build a “single axis” drawing machine in one night.  This machine uses two independently controlled carriages on a single piece of MakerSlide rail to control a pen at the tip of two linkages.  The primary purpose of the project was a fun group build and a learning exercise in setting up a non-Cartesian machine using inverse kinematics.  Kinematics in this case means mathematically describing the machine to the CAM controller.  The One Axis DrawBot is a very simple non Cartesian machine.

kinematics

The equations used are shown above.  The ends of the linkages on the carriages end are at joint[0] and joint[1].  The pen is at pos->tran.x and pos->tran.y.  The first two equations convert the desired pen location back to actual machine locations.  They were plugged into the CAM program.  The last two equations do the opposite and convert machine locations to the pen location.

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One Axis Drawing Machine

We had one team assemble the machine, one team wire the electronics and one team setup the controller.  It took about two hours to complete that phase.  We try to use newbies wherever possible, so adding solder training into the mix usually adds a little time.  The next step was to setup the CAM controller.

mach3

 

formulas

We borrowed the  CNC router computer and control box to run the machine.  This has Mach3 CAM controller software on it.  Mach3 has a “formulas” feature that we used to enter the kinematics.  We quickly had the machine running, but it was soon clear that Mach3 was not completely up to the task.  In the formulas mode, it appears to disable the DROs (digital read outs) which tell you exactly where the machine is.  It was also difficult to home or tell the machine the current location.   Moves in the Y axis are non linear and need to know the current location.  This resulted in Y axis moves that were not 100% accurate.

xy

 

The other problem was coordination.  If you tell a CNC machine to move from X0, Y0 to X1, Y0,  it accelerates up to the desired speed then decelerates to the end point.  If you tell it to move from X0,Y0 to X1 Y10, the two axes are moving different distances, so it needs to coordinate the different axes speeds and accelerations. The X axis would move quite a bit slower to coordinate with the longer Y distance to get a straight line.  Mach3 was coordinating the two machine axes, but it was not coordinating the pen axes.  Moves in only X or only in Y were nice and straight, but moves in both X and Y had a bit of a curve to them, but they did accurately arrive at the end point.  A graphic with a lot of short moves would not show any on the problems above so we ran a quick “PS:One″ graphic.  Watch the video and be sure to wait for the applause.

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We will switch to using EMC2 (LinuxCNC).  This has a true inverse kinematics feature that should fix the problems.

There is some discussion on the EMC user mail list to help us with this project.

Update 6/23/2013:  Here is the latest (untested) version of our LinuxCNC kinematics file mykins.c

 

16

06 2013

CNC Build Club – Gonzo Build #2

One Axis Drawing Machine

This week the CNC Build Club is going to attempt Gonzo Build #2.  A gonzo build is where we try to knock out a complete CNC project in one night.  Gonzo build #1 was the Quantum Delta 3D printer.

Quantum Delta 3D printer

Quantum Delta 3D printer

This week we are going to build a one axis 2D drawing machine.  This uses two independently controlled carriages on the same axis to get 2D motion at the ends of the linkages.  The purpose is only to have a little fun and to cut our teeth on a simple inverse kinematics machine before moving onto a much more complex 6 axis machine.

1 Axis Drawing Machine

 

If you want to help, please join us.  The meeting is open to non members.  Please RSVP via meetup.

09

06 2013

Bitbeam Presentation – CNC Build Club

Bitbeam

This week we have a presentation by Jason Huggins (@hugs) on Bitbeam and the Tapster robot he built with it.

jason-huggins-with-tapster

When:

Thursday, May 9th @ 7:00pm, upstairs in the electronics area

Topic:

Jason will give an overview of Tapster, his open source, 3D printable, mobile app testing robot. In addition to explaining why creating a mobile testing robot is not the worst idea you’ve ever heard of, Jason will give an overview of Bitbeam, the open source building toy that he developed, which Tapster’s made out of. He’ll cover his making journey as he’s experimented with laser cutters, CNC mills, and 3D printers to make Bitbeam. For fun, the talk will also include live demos of Tapster playing Angry Birds.

About Jason:

Jason Huggins is CTO and co-founder of Sauce Labs, a software test infrastructure company, and is the original creator of Selenium, a popular open source web testing tool. In 2011, for an art project he was working on, Jason created Bitbeam – a 3D printable LEGO-Technic-compatible construction toy. Jason lives in Oak Park, Illinois.

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CNC Stuff

Following the presentation we will break away to work on various CNC projects. The ongoing group project continues to be the mid-sized CNC Router. The machine is now fully functional under Mach3 control. We can talk about the Mach3 setup and cut a few things.

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06

05 2013

Last Night’s CNC Build Club

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We had a great meeting last night.  We had over a dozen people working together to wire up a CNC control box.  At one point we had three soldering irons going at the same time.  Here is the pile of parts we started with.

Starting Pile Of CNC Parts

 

Here are some people wiring the box.  A really nice job was done using wire ferruls wherever we could.  How many hands can fit in that little box?

CNC Team Work

Here is the nearly completed box.

Box Almost Done

 

Thanks to Chris, Matt, Aeva, Patrick, Donald, Steve, Jason & Alex, Cat, John, Will, Gabe, Norm, Allen and Colin.  Next week we will be testing the motors, adding limit switches and configuring the software.

We will start with Mach3, then switch to EMC2 when we find a dedicated PC for that.  Chris and John I think mentioned they do time at Free Geek.  I am sure they could find a little PC.

Special thanks to Automation Technologies Inc for giving/lending all the parts.

– Bart

 

 

26

04 2013