One more drawing machine. I’ve wanted to build one for a while, based on an article in the Boy Mechanic, dated 1913.
Download the book here. Look on page 436.
This one is a mash-up of two of the designs in the original article. Come see it at the 2015 East Austin Studio Tour in November!
Valantine’s Day was a great day for the Science Mill opening in Johnson City Texas.
The Science Mill is a new science museum geared to middle and high school students and their families.
The mission of the museum “… is to ignite the curiosity, ambition, innovation and problem-solving potential of the next generation through an innovative, immersive experience that enhances the community’s understanding of, and appreciation for, science, technology, engineering and math (STEM).”
I was privileged to show both a new Van de Graaff generator and my Lissagraph drawing machine at the opening. Enthusiastic Members of the Texas 4H did a great job of demonstrating the Van de Graaff generator as you can see in the gallery below.
My drawing machine and Van De Graaff generator were temporary exhibits for the opening. My wife, Sally Weber has three holograms which are part of the permanent exhibits at the museum.
Please support the new Museum!
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.)
The Lissagraph Construction Details
By Craig Newswanger
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
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
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.
Arcattack was part of the entertainment Friday May 9th, at the Liberty Science Center Genius Gala 3.0.
.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!
I’ll post a video as soon as I get access to one.
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.
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.
I’ve installed and programmed the new motor drivers. I used two Mforce Microdrives and one Mforce Powerdrive modules from Schnieder Electric:
My local distributor for Schneider Electric is Olympus Controls:
Here is a drawing from the new Lissagraph machine:
I’ll post some pictures on Saturday during the East Austin Studio Tour.
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.
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.
Introducing the 6-Pack 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:
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!
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.