A couple of months ago, a neighbor in the middle of a house remodel stacked a ton of wood in his driveway, free for the taking.
I’d been thinking our coffee table was long-in-the-tooth — legs squeaked every time we touched it, and not very mobile – wouldn’t it be great to have it on casters so we could wheel it out of the way to play Kinect games?
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 Instructables.com, 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…
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:
What to do on a rainy weekend? Hey, I haven’t built a model for 30 years! None to be found at the local five and dime (OK, Target, Longs, etc.) Models just aren’t a “thing” anymore. Made some phone calls and found one of Berkeley’s well-kept secrets – the Ace Hardware on University has an entire huge basement downstairs packed to the gills with models and hobbyist stuff. Dusty boxes stacked floor to ceiling, some of them dating back to when I remember building models as a boy (though I couldn’t find the lunar lander or Banana Splits Banana Buggy models I remember building). But we did find Dr. Zira of Planet of the Apes. No, Miles has never seen Planet of the Apes, but it did give us a good opp. to talk about reverse evolution. Model glue is hard to come by these days, but we did find a box of the incredibly stinky enamel paints. Ooooo oooo, that smell! Came out pretty well, but I think he thinks Legos are more challenging.