Introduction: Automatic Card Shuffler

Hello! This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida. ( In this instructable I will guide you through the process of creating an automatic card shuffler. The base components are 3-D printed but the rest of the electronics can be found on

Step 1: Gather the Materials and Tools


3-D Printed parts: 4x Legs, 2x Left Sides, 2x Right sides, 2x Bases, 2x 360º wheels, 2x 45º wheels, Optional Long legs for extra stabilizing (STL files available for download)

4x Motors

2x DC Motor Controllers

1x Rubber Sheet

1x 12 Volt Male connector

1x Off/On Switch

1x LED

1x 220ohm Resistor

1x Potentiometer

1x Black box

1x Bread Board

1x Acrylic sheet, Cut into 11cm X 12mm (2x Front and Back panel) 9.5cm X 8cm (2x Inside panels) 8cm x 10cm (Bottom removable)

1x Arduino Uno R3

8x AA Batteries


Soldering Iron

Hot Glue Gun

Exacto Knife

Wire Strippers

Screw Driver

Circular Saw (For acrylic)

Step 2: Wire Electronics

The first step in the electronics is soldering the motor controllers to each motor. Make sure to leave the wires from the motor controller to the motors at least 10 inches. Then add wires to access the power supply on the bread board and Arduino outputs. Next I would solder the LED and resistor together and combine them into one, then add wiring for the Arduino. Simply solder the input and power for the potentiometer as well. Add additional wiring on either the positive or negative terminal from the batter pack to add the switch to.

Step 3: Test Arduino

Before going further I would recommend testing the motors with the Arduino code. The code reads a value from the potentiometer, that value corresponds to a certain speed the motor should run at. It also sets the rate of the LED to blink. More information on how the code works can be found in the comments of the code itself.

Step 4: Putting Together the 3-D Prints

Now cut out and wrap the four 3-D wheels in rubber, I used hot glue to hold the rubber to the wheel. For the next several steps focus on one side only. First hot glue the wheels to the motors and then glue the 360º wheel to the bottom edge of the 3-D base. Second glue the 45º wheel directly behind the first wheel with enough room for them to booth freely spin. Now take the left side 3-D print and put two small dabs of hot glue where the base will rest and then gently press the base onto it. Let dry for 2 minutes and continue with the right side. Insert the front legs into the assembled top. Follow the same steps for the other side.

Quick Notes:

  • When the base and sides of the 3-D prints come together they should form an even small slit for the cards to slide through.
  • The slot in the center is where the motor wheels will slightly protrude above the surface of the base.
  • The size of the base is only slightly larger then the side length of a card

Step 5: Getting the Black Box Ready

Now that the card shuffler is assembled, lets ready the black box. Pick a side to be the front, then drill a 1/4in hole 3/4 of the way up the box, this will be the hole for the potentiometer. Directly above the potentiometer on the top surface drill a 5/32in hole for the LED to shine through. On the right face of the box approximately 2in from the front side drill a 25/32in hole for the switch. Next make the lines in which the two front legs will be glued down on. They should be 1.5cm from the outside edge and 1cm from the back ledge. Once the legs are marked drill a 1/4in hole right next to one of the leg markings for the wires to feed into.

Step 6: Final Assembly

Unscrew the bottom of the black box and glue all the electronics down. Add additional lengths of wire if necessary. First hot glue the LED to the box just barely sticking through the hole. Next glues the potentiometer and the ON/OFF switch to their respective holes. Desolder one side of the leads for the motors and feed them through the hole. Finally place the 3-D model card shuffler in its respective place and hot glue it down. Now take the acrylic pieces and glue them to their respective places. To make the slot removable, simply glue the bottom and front perpendicular to each other. This will make a free standing piece that can be removed once the deck has been shuffled.