Heading to Houston Mini Maker Faire on Nov. 1st

Houston mini maker faire

 

I’ll be showing my Lissagraph II drawing machine.

Come by and say hello.

 

Yea,the word your trying to remember is Spirograph… its not that, but kind of like that only motorized and huge.

Otherwise, just like that.  It’s resemblance to any mouse-like cartoon character is purely caused by design constraints driven by gravity.

(Scroll down below the picture to read some design details.)

Craig_techshop

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Lissagraph Construction Details

By Craig Newswanger

Mechanical Details

The X and Y cranks are driven through toothed belt drives with a 5:1 ratio. The large turntable for the paper uses a direct friction drive with a rubber drive roller attached to the stepper motor. The friction drive method was chosen for the large turntable to avoid backlash effects that would be visible in the drawings. The turntable is a disk of 1/2” MDF that was cut with a router with a long compass arm.

The drive ratio with the 1 1/2” drive and the 48” diameter disk is roughly 32:1.  I carefully calibrated each motor in the software to compensate for the imprecise turntable ratio and differences in the motor drive clock crystals.

There is a single idler roller opposite the motor that supports the turntable and three hard rubber casters on the back. The 20 degree tilt on the machine insures that the turntable disk is stable and rotates freely. The friction drive roller and idler were purchased from McMaster Carr.

Gravity is very dependable! You can quote me on that!

Motors and Controllers

The drive motors for the X and Y cranks are M062-FD8103 made by Superior Electric. I purchased them from Surplus Sales of Nebraska. The larger motor driving the turntable is a Nema 34 motor. I bought that from a friend.  The controllers are Mforce drives, made by Schneider Electric

http://motion.schneider-electric.com/products/mforce_overview.html

I used two Micro-drives for the x and y motors and a Power-drive controller for the larger motor.

The communications to the motors is through RS-422 serial link.

I use a usb to RS -422 adapter from Digikey # 768-1044-ND

Software

My original code for the drawing machines were created in PureData, a data-flow language usually used for audio synthesis.  I then wrote new code using Processing and G4P user interface tools.  The software really only sends speed commands and Go and Stop commands to the motors. While the machine is drawing the computer is idle.

Speed Ratios and Sensitivity to Initial Conditions

I have been experimenting with this sort of pattern drawing in various forms for many years. I have learned what works to make interesting patterns. People ask if I know what a pattern will look like before I run a particular setting. I have a good idea of the type of image that I will get but there are often surprises that arise from small differences in the starting conditions.

One could refine the hardware so that starting states and phases could be precisely controlled but I’m not sure that would be as fun.

I have also not been interested in pre-visualizing the results using the computer. It is more interesting to see the pattern develop gradually. Observing the machine work is captivating to most people.

Although controlled digitally, the machine can be seen as an analog computer whose output is a direct graphical plot of the algorithm on a piece of paper.

 

 

 

 

 

1 Comment


ArcAttack and Percussibot Front and Center at LSC

Arcattack was part of the entertainment Friday May 9th,  at the Liberty Science Center Genius Gala 3.0.

SamJoeMax_cage

 

“Liberty Science 

Center (LSC

.org) is a 300,000-square-foot learning center located in Liberty State Park on the Jersey City bank of the Hudson near the Statue of Liberty. Dedicated to bringing the excitement of science to people of all ages, Liberty Science Center houses 12 museum exhibition halls, a live animal collection with 110 species, giant aquariums, a 3D theater, the nation’s largest IMAX Dome Theater, live simulcast surgeries, tornado and hurricane-force wind simulators, K-12 classrooms and labs, and teacher-development programs. More than half a million students, teachers, and parents visit the Science Center each year, and tens of thousands more participate in the Center’s offsite and online programs. LSC is the most visited museum in New Jersey and the largest interactive science center in the NYC-NJ metropolitan area.”  from the LSC website

David Blaine donated two coils to LSC from his Electrified event in New York.  Those coils were a bit too big for the LSC theater so Arcattack was commissioned to build a more compact set of coils. I was commissioned separately to build a new Percussibot drum robot for the installation. This is the first permanent installation for a Percussibot!

Sam McFadden did a great job on the coil design. lsc_coil.Yes Sam, that is one sexy Tesla Coil!

 

I’ll post a video as soon as I get access to one.

 

 

 

No Comments


Heading for G4G (Gathering for Gardner)

I’m thrilled to be invited to the Gathering for Gardner in Atlanta this coming week.

An interesting meeting led to an invitation to this great event.  I had heard about the organization but never thought I could attend.

The Gathering is named for Martin Gardner was a popular science and mathematics writer. He had a column in Scientific American magazine called Mathematical Games.  My father and I looked forward to this column and the Amateur Scientist  articles.

The theme of the G4G conference this year is the work of John Horton Conway.    He came up with a fascinating thing called  the Game of Life based on the idea of the Cellular Automaton.

A popular open source version of this game can be found on the Golly website.

A good source for initial patterns for Life can be found here.

I’m making a hologram for the event, of a life pattern in 3D by creating a pointcloud where the x and y are the normal 2D Life plane and the third, Z direction is time.

Here is a 2D hint at what the hologram will look like.  I rarely mention my day Job on my blog.  Its Zebra Imaging, Inc.  We are currently expanding our stock image page.  Send a note to Zebra if you would like to see this image on the stock image page.G4Ghologramsmall

 

No Comments


It’s Alive!

I’ve installed and programmed the new motor drivers.  I used two Mforce Microdrives and one Mforce Powerdrive modules from Schnieder Electric:

http://motion.schneider-electric.com/index.html

My local distributor for Schneider Electric is Olympus Controls:

http://www.olympus-controls.com/

Here is a drawing from the new Lissagraph machine:

Lissagraph Drawing X=3,Y=5, T=1

Lissagraph Drawing
X=3,Y=5, T=1

I’ll post some pictures on Saturday during the East Austin Studio Tour.
Cheers!

1 Comment


Drawing Machine Photo

Here is a picture of the new “machine”.aframe

Its based on an A-frame and has a hinged support on the rear so that it leans back at the desired angle.  Right now its leans at 20 degrees.  The rotating disk, which holds the paper, is four feet in diameter.  The disk rests on two rollers; one is the idler on the left and the motor drive roller on the right.  The disk leans on three casters behind the disk.  Gravity keeps it in place.  This keeps things simple and not overly constrained.  There is no central shaft so the disk center is determined by the two rollers.  I used a router with a 24 inch arm which allowed me to cut a very precise circle.

So far it looks like it will work, it rotates very smoothly.  Driving on the edge insures that there is no backlash with the big disk and provides a 32:1 reduction from the motor.  The NEMA 34 motor has no trouble driving the disk.  The controller in the picture is just being used to test the design.

Next is the two 24″ disks which will be mounted above the 48 inch disk.   As in my earlier machine the pen arms will connect to the smaller disks with a movable magnet with a short shaft.  The two disks will make the whole thing look like a familiar mouse character.

This new design is meant to be suited to display in a gallery or other situation so more people can watch it work.

I have new motor controllers on order.  I hope to have it working for the East Austin Studio Tour in November.  We’ll see.

 

No Comments


New Drawing Machine Coming

I’m working on a new Drawing machine. Lissagraph 2
Though similar to the last machine, it will be larger and a free standing machine that draws on paper up to 4 feet in diameter.

I’ll have pictures of the work in progress real soon.

Cheers.

No Comments


Six Pack Tesla Coil

Introducing the 6-Pack Tesla Coil

Image of a small Tesla coil

I was invited  (and encouraged) to write an article for Make Magazine for an introductory Tesla coil project. This one is a simple spark gap coil using beer bottles for a tank capacitor and a small Neon Sign Transformer (NST).  It doesn’t play music it just makes loud sparky noises.

The article is meant to teach the basic skills and practices to build and tune a Tesla coil using common materials that are readily available. I wanted to provide enough detail and instruction so that a beginner would be successful.  The coil is made to be modular so that the maker can experiment easily and change out bits as they learn how to get bigger sparks out of their coil.  I hope to post a few improvements after the article gets out so folks who wish to, can get a bit more spark length out of their coil.

The print article will be 18 pages and will be in issue 35 of Make Magazine. The web version of the article includes more detailed instructions and is available here.

I hope a few people actually try to build the coil.  The interns at Make built theirs and were thrilled when they got it debugged and tuned up. Here’s a picture of their coil:

Test coil built by Make Magazine staffPhoto by Sean Ragan

Note that they had to add a bottle to tune the coil so its even better than a Six-Pack!

Thanks to Sean, Keith and the rest of the Staff at Make for the opportunity to write an article.  I’m looking forward to the next, maybe simpler, article.  Thanks to Steve Ward for proof reading the article and making sure I got the technical stuff right.

A special thanks to Bart Anderson for his fantastic JavaTC program and his website. Its a great resource for coilers!

Cheers,
Craig

No Comments


Sound of Shadows at TEDx Austin 2013

A person interactiing with sound of shadows

I was pleased to be invited to take part in the TEDx Austin event on February 9th at the Circuit if the Americas. I produced an interactive video and sound piece for the event called “Sound of Shadows”

The installation used Processing 2 running under Ubuntu 12.04 on a Quad-Core desktop computer.

A Creative HD webcam captured the image from a retrto-reflective screen to obtain a high contrast shadow of a person interacting with the piece.  The program then traced a horizontal outline of the person then scanned it at 150 beats per minute to play musical notes based on the persons outline.

As the videos show, guests got the hang of it quickly and had fun manipulating both the imagery and the sound.

I’ll be continuing to work on the piece to both enhance the images and the sound.

Thanks to Brent Dixon for inviting me and putting together a great interactive space at TEDx.

I will be presenting a new version of this piece at the Austin Mini Maker fair in May.

This video shows people interacting with the installation.

The program grabbed a frame on every scan and saved it.  This video shows all 1400 + frames.

If you were there, you might be able to find your picture!

Sorry about the frenetic nature of this video.   The sound is based on a random walk on a c-major scale.

No Comments


Serindipitous Circles

A long time ago, I had an IMSAI 8080 that I built from a kit.  I was working on laser shows at the time and was experimenting with a hand built DAC board for the 8080.  I saw this article in BYTE Magazine called Serindipitous Circles.  The algorithm was real simple but produced some interesting patterns that could be displayed on an oscilloscope.  Graphics displays were hard to come by at the time.

I noticed that the Auduino Due had two built-in DACs, so this was the perfect thing to try on the Due!

The article can be seen here.

I made a quick video with my cell phone.

Here’s the code:

/* Serendipitous circles algorithm from
Byte magazine February 1977
By Craig Newswanger
*/
// Variables
int x,y,xnew,ynew,j;

void setup() {
analogWriteResolution(12);
}
void loop()
{
x=random(32768);
y=random(32768);
for (j=0;j<80000;j++)
{
analogWrite(DAC0,x);
analogWrite(DAC1,y);
xnew=x-y/2;
ynew=y+xnew/2;
x=xnew;
y=ynew;
}
}

No Comments


David Blaine – Electrified by ArcAttack!

David Blaine Electrified

David Blaine near the end of his 72 hour endurance event.

You may know that Austins own ArcAttack was responsible for the massive Tesla coil set-up for David Blaine’s latest endurance event at Pier 54 in New York. Here is Arcattack’s Facebook page.

Look here for some behind the scenes videos.

It was a privilege to work on this project, and although a lot had to be done in a short time, it was very rewarding to see it through a successful conclusion.  The coil electronics proved to be solid.  Kudos to Joe DiPrima and Steve Ward for an excellent design and Christian Miller for the show controller.  Great work by Sam Mcfadden in the design and the build.

Heres a shot of the crew after David left in an ambulance. (Pat Sullivan didn’t make it in the picture though he was there.)

From Left to right, Tyler Hanson, Stephen Chao (David’s Producer), Adron Lucas, Joe DiPrima, Steve Ward,  Craig Newswanger (me).  Other team members: John DiPrima, Pat Sullivan, Sam Mcfadden and Christian Miller

No Comments



SetPageWidth