The MagPi - February 2020

curl https://get.pimoroni.com/automationhat

| bash

This will guide through setting up for driver
software and examples. You may need to reboot
your Raspberry Pi afterwards.

04

Get sensitive
The PIR sensor has three connectors: one
for 5 V power in (which can be provided by the
HAT), ground, and in the centre is the data line.
Operation is very simple. If the sensor is triggered
by movement, the data line goes ‘high’ (outputs
current). After a period of no movement, it goes
low (no current). Its sensitivity can be controlled
by adjusting one of the potentiometers (the left
one when it’s turned upside down – see Figure 1).
The other potentiometer sets the minimum time
for which the sensor reports movement. We could
connect the PIR directly to the GPIO, but as the
HAT is now in the way, we’ll use its inputs instead.

Pimoroni’s Automation HAT

allows the safe connection of all

kinds of input and output devices

These motion sensors use

infrared to detect heat changes

caused by moving objects

Top Tip

Any buzzer

you like

You don’t have

use a loud siren. If

this is just for fun,

maybe a buzzer

may be better, or

could it play a silly

MP3 recording?

Adding alert

notifications allows

you to keep on eye

on things when

you’re away, and you

can add images too

TUTORIAL

Build an internet-connected room guard magpi.cc 43