I started this project due to my parents constantly nagging me about forgetting my house keys.

RFID (Radio Frequency Identification) and NFC (Near Field Communication) are old technologies, but they are just starting to be used in new innovative ways. Today RFID and NFC devices can be found anywhere; phones, offices, even schools. An RFID/NFC system consists of two major components: the reader and the RFID/NFC device. The chip consists of a thin wire connected to a small chip capable of storing a very small amount of data. These chips come in a variety of shapes and sizes such as cards, keychains and even surgically implanted capsules. The reader transmits a small, low power electromagnetic field. When a chip is placed near a reader, it gets just enough power for the it to detect the stored data. Each RFID/NFC chip has a unique code, similar to a serial number.

To make this project I used an Arduino, servo, and an Arduino compatible RFID break out board. I decided to go with a break out board instead of a shield so that it would not look bulky on one side of my door. I started by first finding out what my unique code was, then I wrote a very simple code. The code consisted of a simple “if else” statement, followed by commands for the servo. I had to add a delay into the code for the servo, so that I would have enough time to open the door, walk in and then close the door before the servo moved back to its neutral position.

My door lock is not a typical lock which you turn a handle or pull down a lever. Instead, all you have to do is pull a tab on the side of the lock. This made the project a whole lot easier.

Here you can see the servo is tied to the tab with wire. From there, the servo is connected to the Arduino which is powered by a five volt battery. The wires going to and from the RFID reader underneath the door.  This is shown in the picture below:

Here is the RFID reader on the on the other side of the door:

I chose to keep the reader at the bottom of the door so that I could easily scan my shoe which contained an RFID device.

Here is a video of it in action: