Author Archive

Arduino upgrade

March 3, 2009

For those of you who are working with the Arduino Duemilanove, you might be interested in this announcement from Arduino about a processor upgrade.

“We’re very happy to announce that the Arduino Duemilanove has been upgraded to a more powerful microcontroller: the ATmega328. It’s fully compatible with the previous ATmega168, but with twice the memory. That includes flash memory for storing sketches (32 KB instead of 16 KB), RAM for holding variables (2KB instead of 1KB) and EEPROM for saving data when turning off the board (1 KB instead of 512 bytes). We’ve also raised the speed (in the bootloader) for uploading new sketches from 19200 baud to 57600 baud.

“Thanks to some tough negotiating by Gianluca Martino of Arduino and Smart Projects, this won’t raise the price of the board. Look for distributors to roll out the upgraded boards soon. Current Duemilanove or other Arduino boards can be upgraded by replacing the ATmega168 with a bootloaded ATmega328 (you’ll need to buy a pre-bootloaded one or use a hardware programmer). Be sure to select “Arduino w/ ATmega328″ from the Tools > Boards menu.”



Recap of February 4, 2009 meeting

February 5, 2009

The evening began with Nick recounting the earlier colloquium by Andrew Ng of Stanford about Intelligent Robots. As members arrived we discussed various aspects of AI and robotics.


Recounting last meeting’s coverage of the Kreg pocket hole jig, Jon showed us a Kreg jig in a carrying case that he purchased recently and a shelving project that he did for his wife. He talked about the challenges and successes of putting together melamine shelves.


Also recounting last meeting’s coverage of mold making and casting, Ken showed an acrylic project. Using a small plastic film canister and easily available casting acrylic (fiberglass casting resin, readily available at home centers is tinted grey and will not work for this, so Ken recommended Clearlite casting acrylic available from TAP plastics, Ken has preserved wedding cake for his two son’s weddings as a memento. (Pictures to be posted



Ken also spoke about the use of polymer clays (Fimo or Sculpey) as a modeling tool for making parts. Polymer clay works well for non- functional, decorative items, such as moldings or frills, but for practical parts such as knobs or handles it is too fragile. Instead, sculpt the item you wish to create in polymer clay, fire it at 250 degrees for 20-25 minutes per ¼”, and use the resulting object to cast a negative mold. Then recast the object in acrylic (clear or dyed, or paint it afterwards) and you can create multiple, sturdy items.

Alternatively we also talked about using polymer clay as a one-shot negative mold for casting acrylic or plaster items. Once the medium has set up the polymer clay can be ablated away, leaving the cast object.


Nick showed us the results of his tube-casting, which utilizes the tube mitering template software that he designed.  After creating a complex design of mitered tubes, printing out the templates, taping them together using card stock, and then bracing the tube-template-mold in sand, he filled the tubes with plaster.  There were some voids, and as it turns out the mold was somewhat tilted, but he ended up with a post-modern sculpture which could be a desk ornament or a hat rack. One thing he has learned from this casting experiment is that due to the fine nature of plaster, all of the seams, tape and even some minutely raised lettering on the cardstock were imprinted in the plaster.


New member Walter brought us news of a DIY group in Philadelphia called The Hacktory They have a shared space for working on projects, meet once a month, offer a variety of classes, and … have just received a 3D printer from a fellow inventor.

Walter told us tales of putting this thing together and making it work, and then filled us in on his own Arduino/LED matrix projects.

His goal, to make an Arduino driven 90×90 LED matrix that displays monochromatic grey scale full motion video. As part of his project he is exploring the design and manufacture of sub-components that can be daisy-chained together.


Many of us have expressed interest in a “field trip” to Philly to visit The Hacktory.


Rob has suggested that he will bring in a discarded (but working) B&W television next meeting for us to experiment with, and if Ken can find it, he will dig up his Timex/Sinclair to produce RF output for the TV.


November 14, 2008

While honing our soldering skills at the recent lab conducted by Nick Johnson at Make:Princeton, we began discussing the dangers inherent in working with lead solder (fumes, lead leaching/poisoning, burns) and commented on the concept of dangerous projects in today’s litigation conscious world.

Even the recent best selling book “The Dangerous Book for Boys” by Conn Iggulden and Hal Iggulden is mostly innocuous. Oh, to be sure, there are chapters on tying knots, building a treehouse, making a bow and arrow (“You’ll shoot your eye out, Ralphie!”), and hunting and cooking a rabbit, but these few “dangerous” chapters pale in comparison to boys publications of a century ago.

Take, for example, this opening sentence from a 1913 Popular Mechanics article. “Fortunate indeed is the boy who receives a stock of glass tubing, a Bunsen burner, a blowpipe and some charcoal for a gift, for he has a great deal of fun in store for himself.”

What parent today would give their son a gift of glass tubing and a Bunsen burner and say, “Here Bobby, go learn glass blowing.”? And personally, I had extreme difficulty just finding three test tubes for a project I am working on, and searched every toy and hobby store in a 25 mile radius until I found a package of safety glass test tubes in an educational store with very little else in the way of practical chemical science equipment.

But an article on “Glass Blowing and Forming” is just one of the over 700 truly “dangerous” projects for boys found in Popular Mechanics’ “The Boy Mechanic: Volume 1”. This book, beautifully reproduced and hardbound, is available from Lee Valley Tools.

What do I consider “dangerous”? How about How-To’s on:

  • Etching Brass and Copper
  • Electroplating
  • Creating a Jump-Spark coil
  • Creating an induction coil
  • Generating hydrogen for your own working Zeppelin model
  • Creating an Ammeter and static machine
  • Generating Acetylene gas (where does one readily get pieces of carbide?)
  • Creating a 110 volt transformer
    • and the one that really blows me away:
  • Creating a Lead Cannon

    “Any boy who has a little mechanical ability can make a very reliable cannon for his Fourth-of-July celebration by following the instructions given here:”

Lee Valley Tools has published the four volumes, complete with illustrations, covering 1913 (vol. I), 1915 (Vol. II), 1919 (vol. III) and 1925 (vol. IV) for about $22 each. But you can look at volume 1 and print off your own How-To articles such as “How to Create Your Own Metal Foundry at Home” by visiting Project Gutenberg. Even the images are faithfully reproduced in the PDF version of this book.


Part of being a Maker is exploring this “dangerous” zone and revitalizing the hands on skills of the past. These books will help you explore these skills without protecting your from litigation with the phrase:


The projects you are about to read were conducted by amateurs with years of inexperience …
which is how they learned not to touch a hot soldering iron.



Soldering Lab recap

November 13, 2008

With childlike euphoria I rushed home to show my wife and son what I made, I MADE! With the smell of flux fumes still in my nostrils I hooked the thumb sized circuit board up to a set of batteries and gleefully displayed the two blinking LEDs.


It certainly isn’t the prettiest little contraption (my soldering skills have a long way to develop), but thanks to the knowledge and patience of Make:Princeton leader Nick Johnson, I and two other soldering lab attendees were able to get these simple devices to work.


Nick Johnson explains the schematic

Nick Johnson explains the schematic

Nick began the lab with a schematic drawn on the chalkboard. He described how the circuit would work and added a diagram of the circuit board layout. He then showed us the basic tools needed (soldering iron, solder, snips, strippers, etc.) and after a brief demonstration of soldering technique, he handed out the components and we launched ourselves into our projects.


I had suggested the lab to Nick at a previous Make:Princeton meeting, explaining my deficit of talent and experience in this area. In the 70’s I had attempted building one of PAiA’s simple electronic synthesizers (which ended up in a shoebox under my bed, non-functioning) and later in the 80’s I built a Sinclair ZX-81 computer (which was replaced by the manufacturer with a WORKING model after I sent it back with another $30), so my track record with electronics was dismal.


Jon inspecting his handiwork

Jon inspecting his handiwork

But Nick has patience and loads of supportive enthusiasm. With through-mounted soldering techniques we assembled the 555 IC, two resistors, a diode and two LEDs to a small chopped up piece of Radio Shack Universal PC Board. One by one, Rob, Jon and then I were delighted to see our handiwork light up and blink (not without first learning how to de-solder, wick and clean up our mistakes).


In all it was a very pleasant evening. I intend to pay Nick (and Make:Princeton) back with a lab on metal etching sometime in the next several weeks. If you have an idea for a lab, or want to share a project technique that we could all benefit from, please contact Make:Princeton at


We hope to see you at our next meeting.




Meeting recap

October 30, 2008

Last night’s meeting (October 29, 2008) was held at the Small World Coffee Shop due to the fall break and unavailability of University rooms. Nick and Ken began a brainstorming conversation about a collaboration on an interactive light table. When Rob joined us, an idea was sparked about a table where a servo driven magnet mounted below a box with a light layer of sand would drag a steel ball through the sand to draw pictures. The three agreed to pursue this idea as a collaboration.

Rob showed a hand held version of a vortex cannon (a vortex pistol?) that he built with his 5 year old son. He also showed a prototype of a compact, foldable camping grill to be used by back-packers.

Ken showed his “ThinkWell”, a solid state USB memory farm built in a Steampunk style.

Nick showed pictures of his completed concrete bench with lighted interior cavity.

More detailed posts on these projects to come.

The meeting wrapped up with a discussion of possible future “hands on” demonstrations, such as metal and circuit board etching, acrylic casting, TIG welding, and robotics. We will likely put together an etching demo in the near future.

Come to the next meeting, scheduled for November 12th.