Archive for the ‘Electronics’ Category
I was privileged to attend the 12th Gathering for Gardner. This is a biennial conference celebrating the interests of Martin Gardner.
He penned the Mathematical Games column in Scientific American for 25 years and also wrote about science, skepticism, magic and philosophy.
Here are a few pictures, I’ll post more details later.
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’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.
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!
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
It’s been ages since I posted anything. This is mostly because I was not able to get much time in the shop over the last few months. I’ll try to keep up with the blog a bit better.
I built this stepper motor driven drawing machine based on an idea from a toy from the 1920’s. The Toy is called the “HOOT-NANNY” Yes, really, that’s it’s name.
I scaled it up to create complex guilloché patterns on paper.
Guilloché is the word used to describe intricate repetitive patterns often used in security printing and fine metal working. The machine uses three micro-step motors that are controlled by a program written in PureData. Careful control of the motor speed ratios and positioning of the pen arms results in complex patterns. Some of the best patterns are the result of setting the speeds very near but not quite on specific harmonic relationships. The pen traces a Lissajous curve and the paper rotates beneath the pen, thus tracing out the complex pattern.
The patterns take from 10 minutes to and hour to create.
Puredata is not really intended for motion control but I found it really easy to manipulate the ascii to create the strings for the motors. If I tried to do this in C or Python It would taken much longer to program. In puredata sliders and buttons are a snap. Opening two serial ports turned out to be easy as well.
Special thanks to Olympus controls in Austin.
Thanks to the help of some friends I was able to deliver a working artillery game to the Dorkbot event last Friday night.
Amazingly to me, the code came together Friday morning with lights a-blinkin’ and speakers a-beepin’. The machine came to life at about noon on Friday. I think the game was well received by all the people who took a try. One young fellow pictured here, really got into it!
Special thanks to Angelo Fancello and Oliver Greaves for late night assistance. And thanks to my wife, Sally for her help and patience with the crazy schedule I’ve been keeping.
I’ll post the details here soon, including schematics and “code” (it ain’t pretty but it worked!).
Thanks to RadioShack for the opportunity to produce something fun with RadioShack.