Building LED Flashlights in Altoids Tins

I spent a couple of hours with my son’s fourth/fifth grade classroom today, teaching them to build LED flashlights in Altoids tins. This project was both simpler and more complicated than last year’s Bristlebots project – fewer parts to manage, but we went deeper into electrical and electronics concepts. The students learned about voltage, insulators, conductors, circuit load, diodes, polarity, and various types of switches. And had a great time! Every single kid finished with a working flashlight. Some even enjoyed the process so much they stayed after school to build a second one.

I started with this recipe from, but modified it a bit (we used a single LED and battery to reduce wiring and to eliminate the need for resistors, though we did talk about resistance).

One of the biggest challenges for me was figuring out how to drill clean holes in aluminum – every attempt with a punch or standard drill bit resulted in sharp, ragged, non-round holes. Finally figured out that what I needed was a “graduated” drill bit. Happily, I found one from the 1940s in a toolchest that I had inherited from my grandfather. So not only was the bit we used ~70 years old, but I later learned that my grandfather made all his own bits! He would have been proud to see us using his tools this way.

Sorry I didn’t get more photos of the process – no shots here of drilling or soldering, or of the kids playing with their finished flashlights in a dimmed room,  but was bit busy…

View the Flickr set with captions, or check the slideshow version below.

Visit to The Crucible

Awesome day – I was invited to join a group of journalists as they explored and covered Oakland’s metal and glass foundry / learning center The Crucible. Incredible place – blacksmithing, glass blowing, grinding, enamel work, all forms of welding and cutting, wood shop, Arduino and electronics…. would love to attend, but classes are really expensive. They do have scholarships for the kids classes though!

Embedded gallery below, or check out the Flickr set

As we were wrapping up, one of the old-timers came out of a room with this amazing quadrocopter, which he flew all over the place:

Bristlebots in the Classroom

A year ago, Miles and I made our first Bristlebot – a small robot made from a toothbrush head, hearing aid battery, and the vibrating motor from a cell phone – which skitters around on flat surfaces in chaotic patterns.


The experiment didn’t end well – Miles grabbed a hot soldering iron by the shaft when I wasn’t looking and we had to segue into burn control. When that subsided, we had great fun racing the bot across the floor.

I just volunteered to help his entire second/third grade classroom build their own bristlebots this April. We’ll also try a variant with mint tins and paper clip legs. We plan to build a “sumo” ring they can push each other out of, and may also try our hand at bristlebot painting:

Chris Cerrito’s Vibrobots on Paint from Anderson Miller on Vimeo.

Found a good source for a battery + motor combo pack, which I’ll be ordering in bulk. Now just need to get my hands on a lot of toothbrushes!

Sow, grow, harvest, cook

I’m very taken by the mission statement of the East Bay School for Boys:

By the time he graduates, each boy will:

Examine and acknowledge his own learning strengths and weaknesses and set personal learning goals; collaborate in a community-oriented, project-based internship experience; conduct a conversation in a foreign language about something that he reads in that language; disassemble, diagram, rebuild, and write instructions for something electrical or mechanical; write a cogent persuasive piece on a matter of personal importance; analyze a meaningful passage of another’s writing and declaim it with passion and from memory; sow, grow, harvest, cook and eat his own vegetable; solve a challenging problem in a team; take a leadership role in a project, event or activity of significance; By performing the appropriate research, determine whether a statement by a public official is true; assess media coverage of an issue or event from various perspectives; hold and care for a newborn baby; demonstrate by something measurable a commitment to creating a more sustainable future; conduct a scientific experiment, collect and record empirical data, and produce a written summary of the results with sound scientific conclusions; participate in a physical team competition; mentor another boy in something in which he feels confident; and produce or perform a work of art.

Imagine what the world would look like if every boy and girl in the United States (or world?) could graduate saying he could do all of these things. How would things be different than they are today?

What Makes Finnish Kids So Smart?

Wall Street Journal: In the international PISA test, Finnish students rank as among the smartest in the world. Yet they don’t start school until age 7, have no classes for the gifted, no standardized testing, have plenty of “fruittari-hoppari,” and don’t agonize over college (since it’s free).

Finland’s secret? Not much. Basics. Pride. And, oh yeah – small class sizes and teachers with masters’ degrees. Another interesting difference – a much narrower gap between the highest- and lowest-performing students (4% in Finland, 29% in the U.S.) That’s because in Finland, none of the students move on until the slower students have caught up. Rather than pushing advanced students forward, they’re invited to help the slower ones. The thinking is that they can do so without harming their own progress.

“In most countries, education feels like a car factory. In Finland, the teachers are the entrepreneurs.”

There are good reasons (see article) why it would be hard for the U.S. to emulate Finland’s educational performance, but surely we can learn something by observing? Let’s start with smaller classes, better teachers, and and end to No Child. That seems pretty fundamental.

Music: The Hold Steady :: Cattle And The Creeping Things

Creationist Diorama-Rama

1Stplace Utne Reader, on a Creationist Science Fair that recently took place inside a shopping mall in Roseville, Minnesota, including a diorama explaining how a broken motor disproves evolution, plus fossil evidence that people lived at the same time as dinosaurs.

The projects all used classic high school science language: Start with a hypothesis, move on to testing, and then draw a conclusion. The problem was that much of the science was backwards. In good science, you start with a piece of evidence and try to find a truth. With creationist science, you start with a truth (the Bible), and try to find the evidence.

Music: Isaac Hayes :: Going In Circles