BUILD IT YOURSELF
MAKE A SMART
Our little town of Manitou Springs, CO takes
its Carnival celebration seriously. It seems like
half of the town is in the parade dressed in
colorful and comic costumes, while the other
half is on the streets partying and having a good
time. Beaded necklaces of all varieties are
traded between the participants and many
people have quite the collections. I knew I had
to come up with something special that no one
else would have for our next Carnival, so I
started thinking about making an electronic
necklace of some kind. I wanted something that
was unique, playful, personalized, and
inexpensive so I could give it away if I wanted
to, and wouldn't feel bad if it got broken during
By Craig A. Lindley
Go to www.nutsvolts.com/index.php?/magazine/article/
july2013_Lindley for any additional files and/or downloads
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Having a basic idea of what I wanted, I searched the Internet and found http://tinkerlog.com/howto/
64pixels where Alex Weber had connected a 64 LED
array to a ATtiny2313 microcontroller to make a circuit
capable of displaying static patterns, text strings, and
simple animations. This was basically what I was looking
for. Subsequent searches turned up another site
( https://sites.google.com/site/tinymatrix), where
tigeruppp (who also referenced Alex's work) built a
5x7 LED matrix and a ATtiny4313 into a necklace which
was exactly what I wanted to do. Both Alex and tigeruppp
provided C code for their projects, so I had a lot of
resources to draw upon.
In the end, I used tigeruppp's hardware configuration
and modified his code to build what I'll refer to as a smart
necklace. So, in this article, I will show you how to:
seven animations and 13 static display patterns available
at the touch of a button. In addition, each necklace can
be customized to display a person’s name or other
pertinent text message.
Prerequisites for building this smart necklace include:
1. Having a PC or MAC for compiling the code.
2. Having some knowledge of C program
development; the ability to edit a C program source file
and run a Makefile from a command line window, for
3. Having a programmer for Flashing the code into
the controller (more on this shortly).
4. Having basic soldering skills for assembling the
1. Compile the C code for the smart necklace for
the ATtiny4313 microcontroller
2. Program (Flash) the microcontroller using an
Arduino Uno board as a programmer.
3. Build the smart necklace.
40 July 2013
When we are finished, you will have a necklace with
After having built a few of these necklaces for my
Mardi Gras friends, I realized they would also make great
gifts for our young nieces and nephews; something they
could show off to their friends. If you make these now,
you will be way ahead when it comes to Christmas
shopping, so let’s get started.