Welcome to my first instructable! I apologize in advance for my poor level in English.
In this step-by-step guide I am going to teach you how to build a simple and very cheap NFC Ring Lock Box !
Step 1: What you'll need
Ok first, the idea was to create a box locked from the inside. Many different designs were described and easy to make with Instructables but I decided to create mine.
It had to be the cheapest possible and be able to fit in the top of the box. Also to not take too much storage space.
Cheap Box. I used an unfinished wooden box because you can paint and decorate it however you want. There are many wooden boxes here. But it was too expensive for me so I went here.
Inside system lock. Mine.
Battery and its MicroUSB/USB cable. Mine. It has to be a 5V battery that can be charged and deliver power simultaneously.
Arduino Nano and its MiniUSB/USB cable. Very cheap.
Servo SG90. Very cheap.
PN532 Elechouse NFC. Best One
NFC RING to unlock the box. Official
Micro USB Female to USB Female Adapter. Like this one.
And for sure you'll also need some Basics Tools: 3 Hands, Screwdriver, Driller, Soldering kit ...
Step 2: Connect the NFC reader/writter and the Servo SG90 motor to the Arduino Nano
If you received the same SERVO as me, the 3 pins are stuck together. You must detach them from themselves before continuing.
Connect the red wire to the 5V of the Arduino Nano.
Connect the black to the ground GND.
Connect the white wire to the Digital 3.
For the PN532 you can read this but I will tell you everything you need to know to make it work ;)
First you need to put your PN532 into the I2C mode.
Solder the 4 pin connector.
VCC connect to 3.3V, ground to ground, and Analog 5/SCL and Analog 4/SDA.
Just look at the picture.