Nuts and Volts - September 2017

Rick has training in mechanical engineering; I have training in electronics and programming; and when we combine our respective skills, magic frequently happens. We have created some really fun things — including a DEFCON Uber badge that was on display in the Smithsonian Institution (my contribution to that project was just a bit of code, but I was thrilled to do it). Through our technical collaborations, Rick has become one of my very best friends. I have a similar relationship with my friend, Matt who — like Rick — creates amazing things and sometimes asks for a code or circuit assist. I love collaborating with these two friends/artists, and with many others as well.

Another friend, John, whom I’ve known since our days at Parallax, recently asked about upgrading a project from a BASIC Stamp to the Propeller. I’m always happy to do that! The meat of the project is controlling a stepper motor. I looked in my Propeller library and to my surprise ... no stepper motor object!

Steppers are easy. So simple, it seems, that I have taken them for granted and not bothered to write more than a few lines of embedded code for them. It’s time to fix that.

Stepper Basics

For review, a stepper motor is a special form of brushless DC motor that uses a magnetized rotor (the spinning part) and electromagnetic coils attached to the stator (the stationary case). To turn the rotor, the coils are engaged in a specific sequence which causes the motor to “step.” Have a look at Figures 1, 2, and

3. These are simplified illustrations of the basic methods used to turn the rotor.

Stepping Up to Help Friends

My friend, Rick and his lovely wife, Geanie host wonderful parties. Rick is a special effects engineer who got his big-screen start by building dinosaurs for the first Jurassic Park movie. Over the years, he's built an amazing shop filled with wonderful tools that really is a maker's heaven.

During parties, he gives tours of the shop and shares the things he's working on. There was a point in the middle of one of these tours — between the oohs and aahs of his guests — when he turned to me and said with a smile, "The great thing about our lives is that if we want something, we can just build it!"