# 200KV Capacitor Uses Cake Pan and Bowl

[PhysicsGirl] posts videos that would be good to use in a classroom or homeschool environment. She recently showed a 200KV capacitor made from a cake pan, a bowl, and some other common items (see video, below).

One of the most interesting things about the project was how they charged the capacitor. A PVC pipe and some common hardware made a wand that they’d charge by rubbing a foam sleeve up and down against the dome formed by a metal bowl. We might have used a cat, but there’s probably some law against that.

To discharge, they used the end of the wand and were able to get a 10 cm spark. Based on the dielectric constant for air, they estimated that equated to a 200KV charge. They also discharged it through someone’s finger, which didn’t seem like a great idea.

We’ve talked about [PhysicsGirl’s] videos before. Granted, a lot of this won’t help the experienced hacker, but if you work with kids, they are a great way to make physics interesting and approachable. We wish she’d spent more time on the actual construction (you’ll need to slow it down to see all the details), though. If you really want a capacitor for your high voltage mad science, you might find these more practical. We’ve seen many homemade capacitors for high voltage.

# Electric Train Demonstrator

If you ever want to pique a kid’s interest in technology, it is best to bring out something simple, yet cool. There was a time that showing a kid how a crystal radio could pull in a radio station from all the way across town fit the bill. Now, that’s a yawner as the kid probably carries a high-tech cell phone with a formidable radio already. Your latest FPGA project is probably too complicated to grasp, and your Arduino capacitance meter is–no offense–too boring to meet the cool factor criterion.

There’s an old school project usually called an “electromagnetic train” that works well (Ohio State has a good write up about it as a PDF file). You coil some bare copper wire around a tubular form to make a tunnel. Then a AAA battery with some magnets make the train. When you put the train in the tunnel, the magnetic forces propel the train through the tunnel. Well, either that or it shoots it out. If that happens, turn the train around and try again. There’s a few of these in Internet videos and you can see one of them (from [BeardedScienceGuy]) below.

# Air Quality Sensors in Every Classroom

One of the first electronics projects for the aspiring hobbyist is wiring a sensor of some sort to a microcontroller, and then doing something useful with the new information. [Brock] has taken this type of gateway project and turned it into a way to get his students involved and familiar with electronics. His take on an air quality meter accomplishes both of these goals, and hopefully helps turn all of his students into the next generation of hackers.

The bill of materials is pretty straightforward. Instead of the go-to Arduino, [Brock] has gone with a Particle Photon which has the added benefits of various wireless connectivity options. The air quality sensor is a Shinyei PP42ns which interfaces easily with the Photon. The only thing that might be out of reach of most public high schools (at least in the United States) is the 3D-printed enclosure, although if you have access to one, [Brock] put the files on the project page so anyone can use them.

Of course, we’re big fans of projects that get students involved in anything beyond standardized tests, and this project goes a long way towards teaching students more than how to pass a test. There are many videos and instructions on the project page if you want to try this on your own, but if the cost for the materials is the only thing scaring you off from doing this in your own classroom there are a few other options. You could use ATtiny chips, or try a different style of sensor, or maybe just try out a different project altogether.

# One Dollar Board Targets Students

The Raspberry Pi was made to be inexpensive with an eye toward putting them into schools. But what about programs targeted at teaching embedded programming? There are plenty of fiscally-starved schools all over the world, and it isn’t uncommon for teachers to buy supplies out of their own pockets. What could you do with a board that cost just one dollar?

That’s the idea behind the team promoting the “One Dollar Board” (we don’t know why they didn’t call it a buck board). The idea is to produce a Creative Commons design for a simple microcontroller board that only costs a dollar. You can see a video about the project, below.

# Hacking Candle Extinguishing

Anyone can put out a candle by blowing on it. According to [Physics Girl], that method is old hat. She made an educational video that shows five different ways to put out a candle using–what else–physics.

You might not need alternate ways to put out a candle, but if you are looking to engage students in STEM (Science, Technology, Engineering, and Math), this video along with others from [Physics Girl] might spark interest.

# Open Source Tracked Robot Supports STEM in Africa

A lot of hacker projects start with education in mind. The Raspberry Pi, for example, started with the goal of making an affordable classroom computer. The Shrimp is a UK-based bare-bones Arduino targeted at schools. We recently saw an effort to make a 3D printed robotic platform aimed at African STEM education: The Azibot.

Azibot has 3D printed treads, a simple gripper arm, and uses an Arduino combined with Scratch. Their web site has the instructions on how to put together the parts and promises to have the custom part of the software available for download soon.

You know you can ‘freeze’ drops of water in mid-air by flashing a LED at the right time, right? Well, according to this video you don’t even need a strobing light; just use the frame rate of the camera. Much cooler if you don’t know how it works, in our humble opinion.

#### Now do Junkyard Wars!

[James Cameron] and [Mark Burnett] (the guy who created Survivor) are bringing Battlebots back to the Discovery Channel. The new show is called Robogeddon and calls upon the current talent in the fighting robot world. Our prediction? Someone is going to build an amazing piece of art that will be completely destroyed in the first round; a wedge with wheels will take the championship.

#### A steam engine made out of rocks

[Hansmeevis] just spent 230 hours hand carving a steam engine out of gems. It’s called “Dragon’s Breath” and it’s an amazing piece of work: the cylinder is carved out of quartz, while the flywheel, mount, and base are carved out of jasper, onyx, zugalite, and other semi precious gems. Amazing artistry and it works.

#### Don’t lose a finger on all that science over there

[Dr. W] is a science teacher in Saint-Louis, France. Next year, his students will be learning about reaction propulsion and impulse conservation. To demonstrate these properties, [Dr. W] hacked up an old vacuum cleaner in to a jet engine and built a Pitot tube to measure the 140 km/h wind speed. Google translation.

#### Circuit bending a Sega Saturn

Making cool glitched-up graphics from Ataris and Nintendos is old hat, but not much has been done with circuit bending slightly more modern consoles. [big pauper] found his old Sega Saturn in his grandma’s attic and wondered what secrets this forgotten box held. It turns out he can make some pretty cool sounds and even cooler glitched out graphics. The pic above is from Virtua Fighter; done correctly these glitched low-polygon graphics could easily find themselves in a very stylistic indie game.