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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3D Printed No-Carve Pumpkin Decorations for Halloween

3D printed goggles make the minion.
3D printed goggles make the minion.

I love Halloween for its spooky and amusing decorations and am always amazed by the creativity people put into making jack-o-lanterns.  However, it’s frustrating to put hours of creative work into carving a pumpkin, just to have it rot after only a few days.  The simplest solution is no-carve pumpkin decorating.  You can find articles on painted and embellished pumpkins online, however, I haven’t seen any that explore the possibilities that a 3D printer adds.  So, I thought I’d bring a little high-tech to my arts-and-crafts projects.

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Making MeArm

Fully built MeArm
Fully built MeArm with custom controller.

MeArm is an open-source robotic arm kit by Benjamin Gray and Jack Howard.  They published design files for their robot on Thingiverse and a set of instructions on Instructables.  You can 3D print or lasercut the parts, or you can order them as a kit which includes all servos and screws from Adafruit.  If you create the parts yourself, you’ll need to purchase four 9g servos and assorted lenghts of M3 screws to complete the assembly.

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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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Pi-Bot, an Affordable Arduino Robot

Pi-BotI was recently forwarded a link to the soon-to-be released Pi-Bot robot kit.  The Pi-Bot’s Kickstarter campaign is fully funded and is estimated to ship this June.  This robot kit has many similarities to other Arduino-based robots, but at $75, it is much cheaper than anything I have seen.  This fully complete kit comes with an Arduino-compatible board, light sensor, ultrasonic sensor, breadboard and comprehensive instructions.    It seems like a great follow up for kids who’ve already mastered Mindstorms robotics and are looking to move on with their skills.  If you’re looking for an introduction to programmable robotics at a reasonable price, it’s definitely worth checking out.

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.

A Soft-Circuit Potentiometer Makes Music

I recently received some e-textile components in the mail from an Italian company called Plug and Wear (  In the interest of full disclosure, I should state that the company had seen my past posts on e-textiles and sent some sample products free of charge.  Free or no, e-textiles are pretty cool, and I’ve been enjoying experimenting with the items they shipped.

Soft Circuit Elements
Soft circuit elements sent by Plug and Wear

I received the five different items shown at left.    I was particularly interested in the conductive tape, which comes in a range of bright colors.  I was hoping to use it in lieu of conductive thread for a colorful project, but needed to know its conductivity before determining what to do with it.

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3D Printers with Kids – Part 3 (Printrbot Prints!)

Printrbot printing.
Printrbot printing its first successful job.

After last week’s frustration with the Printrbot Simple, we were on the verge of returning it and looking for a different model.  Research revealed, however, that there was no other 3D printer for a comparable price that is ready for delivery now.  The 20% restocking fee for Printrbot returns was an additional deterrent.  So, I took a deep breath and submitted yet another support ticket.

We had isolated the problem as a  faulty power supply, whose fluctuations resulted in the printer frequently and unpredictably disconnecting from the computer.  Two days after the submitted ticket, I received another e-mail from Dave from the support team.  He apologized for the issues and shipped another power supply, which he assured us had been tested.  It arrived two days later.

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3D Printers with Kids – Part 2 (Printrbot Problems)

The travails of our Printrbot assembly continue (see previous post for background).  On about August 20, I’d contacted Printrbot via the support page on their website about the faulty cable to connect the thermistor (heater for the extruder) to the circuit board, and the AC/DC adapter that had a loose piece wiggling around inside it.  We were unable to complete the assembly without replacement parts for both.

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3D Printers with Kids – Part 1

PrintrBot Simple Assembly
Printrbot Simple Assembly
Assembling the PrintrBot Simple base.
Assembling the Printrbot Simple base.

My middle son shares my passion for all things technical.  He begged for a LEGO Mindstorms robot when he was 7, and though we held out until he was 8, it’s been one of his favorite and most-used possessions ever since.  Buying him birthday presents is always fun, particularly when I get to play with his new “toys”.  Two years ago he became the only kid on the block with his own Van de Graaf generator.  This year, we’d been discussing 3D printers and how cool the technology is.  I figured that in a few years they would be commonplace enough to buy one.  Well, it turns out that the prices have dropped precipitously as a number of 3D printer manufacturers have entered the market.  My son turned twelve a week ago, and a 3D printer seemed like the perfect present.

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