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.

The Joy of Sketchup (CAD for Free)

sketchup_logoI am learning to weld.  I am making a metal frame, and am cutting, drilling and welding stainless steel tubing.  I’d really like the results to be precise, so it seemed like a good idea to model the project before actually laying hands on the metal. I went searching for a cheap (hopefully free) product that would allow me to visualize the project before getting started.  There are a number of free CAD programs available and after reading several reviews, I downloaded a trial version of AutoCad.  It comes with a free 30-day trial period and current students may obtain the program for free.  The software is extremely powerful but challenging to learn, with far more options than I was planning to use.  Since my needs were simple – the design contains only straight lines – I went looking for something easier.

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