Business Card Exchanger

Impress your potential employers by adding a theatrical element to the business card exchange.


This project takes you through the steps of how to create a box that will light up and open when it hears a specific knock.


There is an internal button that will allow you to reprogram the knock.


Here is a video to support the design:



Important Notes:

  • This box does not guaranteed job placement. It only attempts to create a way to leave a lasting impression through the business card exchange.


Step 1: Tools, Supplies, and Skills



Based on your level of experience this project could take several hours to complete.



To complete this project you should have a working knowledge of:

  • Soldering
  • Reading a wiring schematic
  • Working with Arduino and code
  • Working with Rhino



  • Solding iron and solder
  • Heat shrink
  • Wire stripper
  • Safety glasses



  • 1 Arduino
  • 1 stepper motor and motor drive
  • Leds
  • Wire
  • 1 Piezo speaker
  • 1 red led
  • 1 green led
  • 1 Transistor 2222
  • 1 2.2k ohm resistor
  • 1 10k ohm resistor
  • 1 1M ohm resistor
  • 1 small piece of perf board
  • 1 9 volt battery clip and 9v battery



This case was 3d printed, but you can make a box out of any material. I have outlined the steps of how to do the 3d modeling in step KP and also include the .stl file below. You can use the .stl file to directly output to a 3d printer. If you do not have access to a printer you can have it out sourced to companies like Shapeways.


Step 2: Program the Arduino


First, you should open up the Arduino program and attach your microcontroller to your computer. We are uploading the sketch first so that we can test the electronics during each step up the wiring set up.


#1: Download the sketch

Download the file xxxxx.pde at the bottom of this section, copy it to your sketchbook and upload to your Arduino.


Code overview:


Step 3: Lay Out and Test the Circuit


This step will outline how to breadboard the electronics. I have provided a schematic to diagram the breadboard. Since the code is already uploaded to the Arduino, you can test each element as you go to see if you did it correctly.


#1 Wire the Piezo Sensor

Connect the Piezo speaker between Analog pin 0 and the ground. Make sure to interrupt the connection with a 1M ohm resistor.


#2 Wire the LEDs

Connect the red LED to digital pin 4 and the green LED to digital pin 5. Make sure to put a 560 ohm resister in line with each of the LEDs.


#3 Wire the programming button

Attach the button to your breadboard and connect one side to 5v. The other side should be connected to digital pin 2 with a 10K resistor inline to the ground.


#4 Wire the stepper motor


Step 4: Model the Case

Next I will take you through the steps outlining how to model the case. If you do not want to use my box design, I have also attached a drawing that illustrates how the case functions so that you can apply the mechanics to another material. I have also attached the .stl file so that you can print the box yourself.


Step 5: Assemble

Now that your circuit is assembled and box printed, all you have left to do is put it all together.




Final Project Ideas

I have two ideas that I have been thinking about for the final project in Making Studio:

Idea 1:

Revisiting my plush lamp assignment that used the dancing cubes and 3d printing them.  Then I would put LEDs and a controller inside the print so that every time you rotate the cubes the color of the LEDs change.

Idea 2:

Would consist of revisiting my innovation switch assignment that was titled, “secret knock.”  I see it as a business card holder and in order to exchange my business card with some one they would have to perform the secret knock on a box, which would trigger a door to open and reveal a single business card.

SHHHH Secret Knock

For my innovation switch project I used an Arduino to detect a sequence of knocks that would then power a toy motor.  “But wait once you show someone your secret knock isn’t it no longer a secret?!”  That’s not a problem because there is a button that you can press which allows you to program a new secret knock.

The sound is registered by a piezo speaker.  There is a green led that blinks when the correct knock is made and a red led that flashes when an incorrect knock is made.

I 3d printed a custom connected to attach the motor to the padlock.  The first round was unsuccessful because the motor I was using was too weak.

image1 image2

Screen Shot 2015-11-05 at 5.45.29 PM

The code is really long but here are some highlights:

const int threshold = 4; This controls how sensitive you have to knock and can be adjusted from 1-1023.

const int rejectValue = 25;
const int averageRejectValue = 15;

These two rows determine how accurately you have to knock on a percentage of 1-100

const int knockFadeTime = 150; This set how long to wait after detecting a knock 

const int lockTurnTime = 650; Sets how long the motor will run

const int knockComplete = 1200; Detects time in-between knocks 

const int maximumKnocks = 20; This sets the maximum number of knocks 

image3image2  image4

The toy motor was not powerful enough to turn the deadbolt.  I acquired a 12v motor with more torque, 3d printed a new connected and it worked!

Here is the video:

Plush Lamp

Below are a series of images with descriptions that outline my process towards creating an object for the plush lamp assignment.


First I designed and cut out a series of box templates.  These would then be folded into cubes.


This is a process shot of my desk


After constructing all the cubes I measured and cut fabric for the faces of the cubes.


Cutting fabric with my dog Q-Tip!


After attaching the fabric I put felt of the outside and sewed the edges to make the transition between fabrics more seamless.


This is the finished cubes unattached


After making all the cubes and attaching the fabric I created ‘invisible’ hinges using packing tape.

     But it didn’t work and I decided to take it all apart and start over.image3




I discovered a new way to create a hinge system and round two worked out better.


Here is a video in slo-motion!

Tear Down – Motorola Droid Phone

This is my post for the teardown assignment.  My teardown object of choice was a Motorola Droid cellphone.


Taking apart the phone was relatively simple.

image1-2 image2

The tiny screws gave me some trouble, but it was the tiny tiny screws that were the most difficult.  I could not find a small enough screw driver, so I tried drilling it with a dremel.


I wanted to remove the LCD screen.  After failing to remove the screws, I tried prying it off and that is when I cracked the screen.  This is when I began to consider my safety and called the tear down complete.

A list of the removed parts (with pictures):

image1 image2





Hard drive with ram?


This is the part that housed the MicoSD card and Sim card


Micro SD card


Sim card


Some other misc. parts

This was a fun project.  I enjoyed taking an object that was once precious to me and just tearing it apart and destroying it (for educational purposes).