Making Embedded Systems, 2nd Edition

Chapter 14. Motors and Movement

The first time I made a motor move under my software’s control was the moment I fell in love with embedded systems. It is more than blinking lights and sensing the environment. There is something magical about having my code change the world.

Since then, I’ve caused many small fires trying to recapture that rush. If your hardware is good and your software pays attention, perhaps you can learn from my findings instead of recreating them.

Creating Movement

Actuators are what your software uses to make a mechanical impact on its environment. The simplest actuator is a solenoid, which is kind of like a button in reverse. It is an electromagnet that will move a piece of metal: if you set it high, the solenoid is in one position; if you set it low, the solenoid is in another. These are useful for locking things or turning valves on and off.

Haptics are usually piezo buzzers or vibration motors that are used as part of a user interface (like your phone in vibrate mode). While these are often on/off as well, sometimes you can drive them with different frequencies to create musical tones as well as vibration. (Piezos can also be used as speakers, but that’s a bit more complicated.)

However, moving things is a lot more fun if you use a motor that can do more than on/off or buzz a tune.

Whether you are making a bipedal robot or moving a widget along a conveyor belt, motors are where the systems really get to play in the real world. While motors are nifty ...