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Build an NFC-powered door lock

TUTORIAL

Forget keys and codes; secure your private hackspace with fob access!

Build an NFC-powered

door lock

ven if it’s completely unnecessary,

there’s always something quite

exciting about adding extra layers of

security to your workspace entrance,

harking back to childhood days of

asking “what’s the secret password?”

before letting your friends into your den. If you’re

anything like us, your space will have some pricey toys

and expensive equipment in it, so it can certainly give

you some extra piece of mind to have it protected by

an additional barrier from any would-be intruders!

This is a great first project if you’re just getting

started in the world of hacking and Raspberry Pi, as

we’ll learn not only about accepting input to the system

from something other than a standard keyboard

and mouse, but also about operating a relay switch

to control an entirely separate (and higher voltage)

electrical circuit.

Before we get started we’re going to assume that

you already have your Raspberry Pi all set up with the

latest version of Raspbian installed and up-to-date.

With that all ready, start by connecting up all the

hardware components.

First, plug in the RFID reader to any of the USB

ports. This type of reader is especially easy to work

with as it acts just like a keyboard, in that the operating

system sees the data contained in any fob presented

to it getting typed in, followed by a new line. To see

this for yourself, open up a text editor and then hold

each fob to the reader in turn; you’ll see a string of

numbers getting quickly typed in followed by a newline

character each time.

GPIO PINS

Next, connect your relay to the GPIO pins. It’s a 5 V

relay, so the positive pin (which will be labelled either

Paul Freeman-Powell

Paul is a technology

enthusiast, geek,

writer, presenter, video

producer, YouTuber,

drummer, husband, and

father to three children,

including twins. You

can find his website at

switchedonnetwork.com

E

Above

The finished build

with all components

connected. The

Electronic Door Strike

is powered by a

separate 12 V power

supply and switched

by the relay switch

@paulfp