LED Matrix Handbag 2.0 – Coming Soon

I recently made a simpler and more attractive version of the LED Matrix Handbag to bring to the Bay Area Maker Faire.  It is far easier to sew than the original, with more streamlined and compact electronics.    Hackaday spoke to me at the Maker Faire about the handbag, and published the interview. If you’re interested in making one yourself, I plan to have a project write-up finished within the next few weeks as soon as I can get to it.  It’s here!  In the meantime, here are some pictures and footage of the latest LED Handbag:





Tweet My Purse! (LED Matrix Handbag)

Handbag displaying "hi"
Handbag displaying “hi”

My goal with this project was to create a wearable electronics project that incorporated the electronics in an organic and subtle way.  The end result is a handbag containing a programmable 10×6 LED matrix hidden inside the lining, with the LEDs visible from behind metal eyelets.  The LED matrix is controlled by a Teensy 3.2,which connects to an iPhone via an Adafruit BlueFruit BLE UART Friend.  The Adafruit Bluefruit App on the iPhone subscribes to a MQTT feed (from Adafruit.io in this case), which streams data culled from Twitter via IFTTT.  Any tweets with the hashtag “#wearables” have their Twitter handle displayed on the handbag’s LED  matrix.  Video demonstration below:

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Entering the IoT with CheerLights and Adafruit Huzzah

CheerLights with Huzzah showing blue.
CheerLights with Huzzah showing blue.

It’s hard to avoid the Internet of Things (IoT) these days.  I thought I’d join the trend by starting simply.  I was inspired by the CheerLights project, which uses a Twitter feed to synchronize the color of lights around the world.  I first saw it through a link to an implementation by Dr. Lucy Rogers, who made a color-changing Christmas tree to adorn the cast on her arm.

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EtchABot: a CNC Etch A Sketch

The EtchABot - a CNC Etch A Sketch
EtchABot – a CNC Etch A Sketch

EtchABot turns your Etch A Sketch into a CNC (Computer Numerical Control) drawing machine.  I’m really excited about this project because of its versatility and its well balanced combination of entertaining and educational aspects.  It’s always fun to hack a toy to do something above and beyond its original intent, and if you build the EtchABot and run the example Arduino sketches, you can make:

EtchABot Gallery

There is an EtchABot Arduino library, so it’s also easy to program it with your own ideas.

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Making Uncanny Eyes

Spooky eyes blink, move and even dilate their pupils.

My middle son and I have a tradition of incorporating electronics projects into our Halloween costumes. This year we saw the tutorial for Uncanny Eyes on Adafruit, written by Phillip Burgess, and instantly decided that we had to make them. The project uses two TFT or OLED screens to create realistic moving and blinking eyes controlled by a Teensy 3.1. This post documents our build process and how we’ve each decided to use the eyes differently in our Halloween costumes. It will make more sense if you’ve read the tutorial on Adafruit, however, you should still be able to follow along even if you haven’t.

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YAWP – Yet Another Wall Plotter

 The Inspiration:

I’ve been very slow to create posts these last few months.  I like to think it’s not due to laziness, but just that I’ve been so busy playing with other projects.  I’m pushing myself to write up the more interesting ones.  These days I’ve been obsessed with machines that draw.  The biggest of these projects has been my wall plotter, nicknamed YAWP (Yet Another Wall Plotter).

A wall plotter (also known as V-plotter or polargraph) works by moving a pen around a vertical (or slightly angled) drawing surface by means of two motors attached to string or a timing belt.  Although wall plotters are really just very slow, low resolution printers, the potentially unlimited scalability and numerous variations in the output make them compelling to watch.  Because of their simple design and because it’s fun to watch a machine drawing with a pen, they are far more engaging than a typical desktop printer.

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Halloween Photoresistor Circuit

Spooky skeleton’s eyes glow when it gets dark out.

Here is a simple project we made for Halloween.  We used a photoresistor and a couple of LEDs to make a spooky skeleton with eyes that light up when it gets dark out.

The Parts:

  • Small rubber skeleton (Party City)
  • Tiny breadboard (I cut a larger breadboard into pieces)
  • Resistors (68 Ω and 82 KΩ or similar)
  • 2N2222 Transistor
  • Photoresistor (eBay)
  • Two red LEDs
  • One double “AA”  (or “AAA”) battery box – as long as the output is 3V
  • Small piece of insulated wire

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Squishy Circuits – Color Mixing with Light

A color-mixing squishy circuit.

A Math/Science activity night is coming up at my kids’ elementary school, requiring a 30 minute class project. I decided to check out squishy circuits. They consist of two kinds of play-dough, one conductive and the other resistive, which can be integrated with other electrical components to make interactive (and squishable) circuits. The instructions for making the dough and some different ideas for types of circuits can be found at the University of St. Thomas’s website.

I made three batches of conductive dough in red, green and blue, and an equal amount of the resistive dough in white.  Most of the squishy circuit examples online showed ways to hook up several LEDs in parallel and series.  I thought I’d try to demonstrate how the resistance of dough increases along its length by mixing colors with an RGB (Red, Green, Blue) LED.

Finding Fritzing

A Fritzing diagram of a breadboard layout with an Arduino Nano.
A Fritzing diagram of a breadboard layout with an Arduino Nano.

I’ll be running a hands-on Arduino workshop this Saturday, where the attendees will be assembling simple circuits and connecting them to an Arduino board.  Recently I’ve been trying to write up clear wiring instructions for a handout.  This is one of those situations where a picture is worth a thousand words.  I’ve seen circuit diagrams in other people’s projects on the internet, but assumed I’d have to purchase some expensive CAD software to create my own diagrams, or just take really good photos of my circuits.  Fortunately, I was browsing an Arduino tutorial on Push Buttons when I noticed that their circuit diagram caption said “image developed using Fritzing“.

It turns out that Fritzing (available at fritzing.org) is open source software for producing professional looking circuit diagrams, breadboard layouts and blueprints for PCBs (printed circuit boards).  You can start with a breadboard layout of your project and use Fritzing to turn it into file for PCB production (see tutorial here).  It’s easy to use, and includes a large number of standard parts (including all of the Arduino boards) to drag and drop into your breadboard layouts.

I downloaded the Windows version of the software and spent last night playing around with it.  It’s very easy to produce great looking breadboard layouts and circuit diagrams.  For educators, designers or anyone who’d like to be able to share their electronics projects with others, Fritzing is a great tool to have.