Shopping List - Painting Electric Circuits

This has gotten to be a bit of an obsession over the past few days. Using paint to create electric circuits.

Seriously, it is all I can think about. I am making a lot of  "this sweater is OK, but it would be awesomer with some LED light bulbs" statements that make my children hover between interest and a deep tween embarrassment that only mothers can induce.

It started with a CNN article on Pens that can be used to draw circuits. I know, great idea.

Except they are from the UK, and kind of pricey (12 pounds which is about $18 today). And according to my sources on twitter the conductivity isn't great once it is dried over long distances. That said the site has some nice classroom kits that include thumbtack batteries. There has been a hollow empty void in my life that is filled now that I know thumbtack batteries exist - you know what I mean?

Also according to the website these pens are available in Radio Shack, so good for those of us stateside.

Think Geek Conductive Paint

For about $30 you can get a 50ml tub of paint from Think Geek. I have visions of renumbering the computers in my lab using this ...possibilities are endless.

This appears to be the same company, so it is probably the same stuff that is in the pens, but it is a better price point for just the paint.

I also found a video describing how to make copper based conductive paint. Sounds fun, but given my overall free time...I might just head to Radio Shack.

MIT also has some resources listed:

• A Kit of No Parts has a great list, including sources

One of the main reasons I am interested is the application for wearable electronics. I am curious to see if the paint can be used to attach conductive thread to the power source. I'll let you all know if it works.

Need more inspiration? Here is a video of interactive wallpaper made with conductive paint. It plays music.

We do some very simple circuits and logic gates in the APCS Principles class suing play-doh. The play-doh works well because it can be changed and experimented with very easily, but the stuff dries out so nothing can be taken home. This paint would make a nice extension, especially if they can make something to take home. Prototype in play-doh then paint for permanent.

Make an Inside Out Computer

For the end of the year my AP students are working on projects. This year I left it very open ended, use anything in the lab and just make something awesome.

They can make with code or something physical. I have students doing everything from a scratch version of Doom to building a cell phone signal amplifier.

One of my favorites at this point is this - the Inside-Out Computer. The parts are all recycled from a couple of old 486s that were donated. Once we can find a non USB mouse the plan is for them to load Linux on it.

I'm pretty excited about having this in the lab next year when we need to teach hardware. 

I am particularly excited about this for next year when we go over computer hardware. Having a running computer while you point out all the various parts and pieces seems like it will be very helpful.

Basically they're attached all the parts to an old plastic crate using zip ties. The have booted it up several times and it works perfectly, except for the no mouse thing.

We have five weeks from the AP exam until the end of the school year, which is a lot of time to fill. In order to get grades on the books I give them a daily Ted Talk to watch and respond to on a discussion board. More on that later.

Update: Another student turned in their final project today. It is a bike with a chainsaw motor added to make a moped. Did all the welding themselves. I was kind of expecting a poster, then they rolled this in:

Amazing!

Computer Science Recipe: Sidewalk Chalk Prototyping

We do this while the kids are working on their Programming Portfolios in the APCS Principles class. We pick a sunny day early on when they start this portfolio and head outside.

Ingredients:

• Markers
• Blank Paper
• Sidewalk chalk - feeling crafty? Here's a recipe
• Sidewalk

Steps:
The Portfolio for Programming is a partner project. A lot of the writing they will have to do will analyze how the program came together. It is helpful for teh students to stop and draw out the program so they have a clear mental piture of what it is supposed to do.

At the beginning of class I give each pair some paper and markers.  I ask them to draw a picture of what their program does. They can illustrate it anyway they want, but no words.

I then have them do an elevator speech and present their drawing to the class. They have 30 second to give a snapshot of what they are working on.

Towards the end of class we head outside. For this drawing they are illustrating how they will create the program they described. I do not give any structure to this.

We then do a chalk walk and each team describes how they plan on solving the problem.

The main point is to get them really describing what the program does and how they intend to get there.

Play - Doh Logic Gates

Still working on Logic Gates in the Cs Principles class. Today they constructed logic gates using play-doh.

OR Gate

We started we watched this video connecting logic gates, AND and OR gates to binary numbers.

Before we did the logic gates I gave them a few challenge problems. I gave them a truth table and they had to construct a logic gate to produce the result. We used the logic.ly website to demo. Want to try one? Here you go:

Then they made logic gates with play-doh. The materials are fairly cheap. The most expensive part are the batteries and the battery holders (these run about $3). The good news is this activity works well with groups of 3 - 4 students, so you don't need a lot of these.

Materials:

• Play-Doh 
• LED lights
• Battery Holder (I use rechargable AA batteries)

I personally do not use the insulating play-doh. I am sure it would be helpful, but I barely have time to cook dinner for my own kids this week, much less make craft supplies.

I left the instructions very open ended. Each group got two battery packs, an LED and some play-doh. The instructions were to make an OR and an AND gate, and take a picture of each.

Post on PlayDoh circuit Ted Talk