WEBVTT

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In the next few lessons, you are going to learn how to detect movement with a Pir sensor and your Raspberry

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Pi.

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But before that, let's get a bigger picture of where we are right now in the course.

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At this point, you already have a good foundation with Raspberry Pi, Python three and the Gpio.

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This foundation is extremely important and will help you in the future.

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From now on with each section, you will discover new functionalities and fun features that you can

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implement on your Raspberry Pi.

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And then at the end of the course, we will do a nice project together where you will use all the knowledge

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you got from all the sections from this course.

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So for now you have basics in Raspberry Pi in general in Python three and Gpio.

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What we are going to do is to focus on using a Pir sensor to be able to detect some movements with your

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Raspberry Pi.

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And first, what is a Pir sensor?

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Pir means passive infrared.

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We as human are emitting some infrared light which depends on the temperature of our body.

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We cannot see the infrared light with our eyes, but the Pir sensor can detect it.

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And in fact, the Pir sensor will detect variations of that infrared light, which means, in other

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words, movement.

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So basically a Pir our sensor will measure the infrared radiation in front of it and detect movement.

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Note that the Pir will not be able to specifically detect if there is someone inside its range.

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Okay, if you are in the range of a Pir sensor and you don't move, then the Pir sensor won't detect

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you.

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You have to make some movement so that the Pir sensor detects something in real life.

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Pir sensors are used everywhere, and you have probably seen some of them to automatically turn on a

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light, to trigger an alarm, etc..

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And so this is the Pir sensor we will use here with this photo.

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And the model reference is HC-SR5 hundred and one.

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It might look like a complicated name, but it's actually a super common component and it will be quite

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easy to use.

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So the output of this sensor is very simple.

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It is a binary output.

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Either there is a movement which has been detected or not.

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We will use Gpio to control the sensor.

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And you will see that if you know how to read data from a push button, then reading data from the Pir

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sensor will be quite easy.

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And at the end of this section, you will be able to connect the Pir sensor to your circuit to read

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and interpret the component data in your Python program.

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Let's get started.