CHAPTER 30

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Pulse-Width Modulation

This chapter explores pulse-width modulation (PWM) using the Raspberry Pi. PWM is applied in motor control, light dimming, and servo controls, to name a few examples. To keep the hardware simple and the software small enough to read, we’re going to apply PWM to driving an analog meter in this chapter.

While the CPU percent-busy calculation used here is a bit cheesy, it is simple and effective for our demonstration. The meter deflection will indicate how busy your Raspberry Pi’s CPU is. We’ll demonstrate this using a hardware and software PWM solution.

Introduction to PWM

The GPIO output signal is a digital signal ...

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