CODING

Tutorial
STEP BY STEP
ROB ZWETSLOOT
Tinkerer, sometime maker,
other-times cosplayer, and
all-the-time features editor
of The MagPi.
magpi.cc / @TheMagP1
PISPY CAM
Set up a motion-activated spy camera in your room to find out
You’ll
Need
> Pi Zero
> PIR motion
sensor
magpi.cc/
2gCQKPj
> Raspberry Pi
Camera Module
magpi.cc/28IjIsz
> Pi Zero camera
cable adapter
magpi.cc/
2gT2KwE
> Portable battery
if anyone’s coming in when you’re not there
W
e’ve all been there. You’ve gone out for the day
and you know you closed your bedroom door,
but you come back and it’s slightly ajar. Who’s
been in there? Were they friend or foe?
>STEP-01
Connect up the camera
Attaching the camera to the Raspberry Pi Zero is easy,
and if you read our camera beginner’s guide you’ll
already have an idea. You’ll need to first switch out the
cable in the Camera Module with the adapter for the
Pi Zero. Gently pull down on the clasp that keeps the
ribbon on the Camera Module attached and remove
the cable. Take note of the orientation of the silver
A very simple Fritzing diagram
just to make sure you know
how to wire up the sensor
connectors on the cable you removed, and make sure
your adapter cable is the same way round when you
insert it. Put the other, smaller side into your Pi Zero,
with the silver connectors facing towards the board.
>STEP-02
Wire up the circuit
The circuit for this is fairly simple, especially as the
PIR doesn’t need a resistor as part of its setup. The PIR
comes with three connections: VCC, GND, and OUT.
VCC needs to be connected to a 5V power pin, GND
needs to go to a ground pin, and then there’s the OUT
wire which will be our input. We’re connecting it to
pin 8, also known as GPIO 14.
If your Pi Zero has GPIO pins attached, you can do
this via a breadboard; otherwise you can loop the wire
around the pin holes and use a bit of Blu-Tack to keep
them in place, or a dab of glue from a glue gun on a
low setting. Soldering is also an option.
>STEP-03
Get the code
Write up or download our code for this project. This
code uses two libraries: GPIO Zero and the standard
picamera library. GPIO Zero can be used to get a
reading from the PIR motion sensor very easily, which
can then be tied into the picamera code so it takes a
photo when motion is detected. We make sure the
photo is given the time so you know when it was
taken, and it then waits five seconds before seeing if
it should take another photo. Save it as spy.py in the
default home folder.
>STEP-04
Final preparations
You can run it first to give it a test. You might want to
change the sensitivity, which you can do by adjusting
62 January 2017
raspberrypi.org/magpi