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W03. Movement 03

Last time we discussed basic mechanics and DC motors. Today, we will discuss the control of movement from a signal standpoint. The principle of movement control is a simple process with a complicated sounding name: Pulse Width Modulation (PWM).

In fact, you've already seen it in the first lab, and it's a natural principle for anyone who has driven a vehicle. It's just a formulation of giving something gas: the more "on" something is, the more it goes.

Pre-readings and Videos​

The readings for today focus on signal amplification, which we have to do to control our motors with low-voltage devices like Arduinos.

The Transistor​

Transistors are the foundation of our modern computing era. This video explains the historical positioning of transistors from a time when they were new enough to be exciting.

Transistors as Amplifiers​

This is a good background for mixing higher and lower voltage components, which we do in this class. It's a waste to build our computers to run at high voltages because all of the parts would need to be engineered differently, and would likely be a lot larger and hotter. But we can't make motors move with only 5V. Therefore, we need to use low-voltage logic (5V) to drive high-voltage (12+V) motors.

Pulse Width Modulation (PWM)​

Pulse Width Modulation (PWM) is a fundamental encoding system that we use in this class, and it also teaches you to think of your signals very practically.

Motor Driver Tutorial​

This is a good reference for the motor driver we use in this class.

Metamaterial Computing​

This paper takes the mechanical computer principle and brings it full circle by simulating digital logic gates with flexible 3D printed parts. It helps us question whether computation is actually something that needs to be done by a "computer," or whether it is something more abstract and fundamental.

Summary of the Day​

Learning Goals​

  1. Learn how to wire and program the L298N motor driver.
  2. Understand pulse-width modulation (PWM) and apply the underlying principle to drive output systems like motors.
  3. Design electro-mechanical encoding schemas using PWM as inspiration.