Introduction: Hide-A-Key

This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (

This is instruction on how to make a Lock Bock that is RFID activated.

Step 1: Created a 3-D Model on the Computer

This is a step that requires a lot of imagination. You have to visualize dimensions for the lock box in order for all parts to fit inside but also small enough so it's not too bulky.

There are three components to the lock box. The first is the drawer. This is the piece of hardware that holds the motor, circuit board, RFID sensor, battery, key, and gears. It is the most difficult part to design because there are several different components that go inside. Within the drawer needs to be a pocket were the gear assembly can be placed. In addition there should be a spot where the servo should be attached. Lastly there should be hole in the front for knob to be attached.

The second part would be the casing. This hold the drawer and also has a pocket inside so when the servo is activated the gears can lock the drawer in place. The difficult part here is to dimension the box so it fits the drawer perfectly and also making sure that the walls are thick enough so it stays strong.

The final part is the knob. This is the easiest part. This just makes it easier to open and close the drawer.

My .stl and inventor files are attached.

Step 2: Printing Your 3-D Parts

When printing your parts you need to make sure that you are using the right tools in order for the part to come out right. The part needs to be placed in the correct orientation so that the least amount of supports need to be made. Several supports were needed while created the drawer where the gear assembly goes. The best way to clear that out is with tweezers and a small amount of sand paper.

After printing you need to ensure that all your components fit in the printed parts. Make sure the drawer slides freely. You may have to modify the 3-D computer model several times before you get this perfect.

Step 3: Creating Your Arduino Sketch

The goal when created the Arduino sketch is to be able to scan a card and have it activate a servo. It is important to make the sketch so that each time you scan the RFID it will either open the lock or close it. There are a few libraries that need to be included in the sketch in order for the RFID to work.

The Sketch includes a chart on where to connect everything.

Step 4: Connect Hardware

Connect circuitry as per the diagram shown.

Step 5: Insert Everything Into Assembly

Insert all parts into the drawer and secure with glue. Make sure to cut wire so there is not a tangled mess within the assembly.

The last thing you will do is test and troubleshoot.