Ultimate Touch Free Dollar Bill Gadget

Even before the Coronavirus Pandemic, dollar bills have always been known to the common person that they are one of the dirtiest objects you can touch on a daily basis. This means that especially in this period of the pandemic, it is even more crucial to be extremely cautious about the places you put your hands on. You never know when you forget you can't touch your face whenever your eye itches, you need to wipe your mouth after eating, or you got a little something stuck up your nose (Fun Fact: You touch your face more than 16 times an hour!).

When designing the product, part of the reason I created an attachable gadget instead of creating a whole new wallet was because it isn't convenient to the consumer. What person would get out of their way just to buy another wallet that they already own? However, something like the Touchless Dollar Bill Gadget that can be easily attachable to the current wallet you already own can create a lot more buyers. Similar to how people buy phone cases, pop sockets, or a phone credit cardholder.

Putting it in simple terms, the design of the Touchless Dollar Bill Gadget has multiple extendable grabbers that are controlled by a string attached to a servo motor. The servo motor would spin in a certain direction which would cause the string to loosen or tighten up. Because the extendable grabbers have a rubber band holding potential energy that is constantly forcing the grabber to pull out, loosening the string would make the grabber pull out and tightening the string would make the grabber close back in.

Some critics might say, why don't you just wear gloves to avoid getting the germs on your hands? Think about it. Where do you often use cash the most? Not the groceries because a person usually spends a lot of money and it's better off to scan a credit card. How about eating out? Yes, nobody wheres gloves on when they eat, therefore, it is simply inconvenient to go through the hassle to put gloves on after you eat, not to mention taking them back off to drive away. Furthermore, some people don't take the precaution to take gloves off the correct way. If you touch the outside of the glove, the steering wheel and any surface you touch in the car can be infected. So why not solve this money and germ problem from the very start with the Touch Free Dollar Bill Gadget.

Steps for Building:

Building the Extendable Grabbers:

1. Download and 3D print the files located at the bottom (short stick, long stick, right grabber, and left grabber)

2. Watch this video to learn how to assemble the gripper: https://www.youtube.com/watch?v=kSzZVy1kScY

*Instead of using wooden sticks demonstrated in the video, screw in your 4mm M2 screws (look at the photo below for good references to better build the grabber).*

• Look at the grabber's joints to see which stick is under which stick
• Note to have the right and left gripper's bumps facing towards each other and the "long stick's claws" pointed upward when assembling.
• When screwing the final screw at the top, loop through a thread (doesn't matter how long because we can trim it off at the end) and screw the screw in normally.
• Lastly, wrap a rubber band around the claws of the "long stick" (I double wrapped my rubber band, but it depends on how big of a rubber band you are using).

3. Don't screw the very bottom joint quite yet because we will attach that to the cardboard money divider.

Building the Money Dividers:

1. Get our your cardboard and cut out five 1.5 cm by 21 cm strips of cardboard(Keep in mind every wallet is different, so the length may differ. Measure the length of your wallet and size it proportionally.)

2. On the five sheets of cardboard, drill small holes 5.2 cm away from the edge of the cardboard. Drill another small hole 4.5 cm away from the edge of the cardboard.

Later on...

• The string will loop through the hole 4.5 cm away from the edge
• The bottom joint of the extendable grabber will be screwed into the cardboard to secure the grabber tot he money divider

Attaching Extendable Grabber to the Money Divider:

1. Carefully examine in the photo the way each grabber is "sandwiched" between the 5 sheets of cardboard cut-outs. After matching the grabber's bottom joints with the holes 5.2 cm away from the edge, use the 8 mm screw to screw the grabber in place. Lastly, loop the string attached to the grabber through the hole beside it (the hole 4.5 cm away from the edge).

- *Alternate sides each time you finish screwing in the grabber in place.*

2. When testing the grabbers out, the grabbers often got stuck between themselves when being pulled up or down. Therefore, in order to make that not happen again, cut out 12 pieces of 2.2 cm by 1 cm cardboard and hot glue 4 stacks of 3 cardboard to each other.

3. Use the hot glue gun again to glue the cardboard in the location seen in the photo below:

4. To make life easier later on throughout the project, take your sewing needle and loop each of the strings through the hole (located at the bottom middle of wallet) in which most bi-fold wallets have.

5. Use tape or hot glue to tighten up the edges, so it's easier to fit in the wallet.

Building the Servo Holders:

1. Get out your cardboard once again, and use an Exacto knife to cut out a 68 mm by 90 mm rectangle

2. About 4.2 cm away from the left edge of the cardboard, make four 2.25 cm by 1.15 cm rectangular incisions.The four rectangular incisions should be separated or spaced by around 3.5 mm.

(See photo below to guide you)

3. Get out your acrylic sheets and use your Exacto Knife to cut four 1.5 cm by 3 cm rectangles.

4. Mark with a pen the middle of the of your cut out.

5. Get out your lighter and heat the middle of each acrylic sheet, so that you can bend it into the proper shape as seen in the photo below (Don't bend it so the sides are completely parallel. Make sure there's somewhat of an angle to it). I recommend using tweezers to hold the acrylic sheet, so the heat doesn't burn you. (*Be Careful*)

6. Superglue the face of an edge of the acrylic sheet to the back of the cardboard cut out (the side that has a larger surface area)

7. Because continuous 360 servos are a little expensive, we will be hacking a normal, cheap micro servo. Watch this video to get full instructions on how to hack a micro servo into a continuous 360 servo:

(The main take away from the video in hacking the micro servo is disconnecting the potentiometer and cutting off a piece of plastic connected to a gear to allow full rotation.)

8. In the package when you receive your servos, get out the smallest looking white, attachable spinners. Use scissors to cut off part of the plastic, so only 2 holes are left on the white, attachable spinners(see photo below for reference).

9. Finally, slowly and carefully fit the 4 servos into the "pockets" made for them. Make sure the white, attachable spinners are closest to the left.

10. Use the rest of your 8 mm screws to secure the servo in place using the holes provided on the left and right of the servo.

11. Fit the Servo Holder into the right pocket of your wallet using the acrylic sheets

What it should look like in the end:

Building the Button Pad:

1. Get your foam and cardboard out and cut out a 4.5 cm by 5.5 cm foam rectangle and cardboard rectangle

2. Use your Exacto Knife and cut 3 slits along each line (Just make sure the slits are in a straight line, no need to precise with the slits). Evenly space them out as well to make it more visually appealing.

3. Get your 8 pushbutton switches out and fit the wires into each slit.

4. Get your soldering iron and jumper wires out and solder the ends of the wires together (To make it easier, use tape to hold the wires down when soldering).

5. Superglue the parts of the cardboard that isn't covered in wire to the foam rectangle. Then superglue the last 2 acrylic sheets on the long side of the rectangular foam.

6. Finally, using the acrylic sheets, fit the Button Pad into one fo the verticle pockets on the right side of your wallet.

ASSEMBLING ALL THE COMPONENTS TOGETHER!

1. Grab your Money Divider and Extendable Grabber and carefully fit it into the Dollar Bill compartment of the wallet.

2. Then, tie each string to an individual servo motor by making a not on the first circle from the center (see picture below).

3. Make sure the wiring is correct by following the schematics.

And You're Done! :)

**Don't forget to check out the Demonstration and Explanation Video at the Top of the Page!**

Schematics:

Code Used:

#include <Servo.h>
int servoPin1 = 13;
int buttonPinPull1 = 9;
int buttonPinRelease2 = 8;

int servoPin2 = 12;
int buttonPinPull3 = 7;
int buttonPinRelease4 = 6;

int servoPin3 = 11;
int buttonPinPull5 = 5;
int buttonPinRelease6 = 4;

int servoPin4 = 10;
int buttonPinPull7 = 3;
int buttonPinRelease8 = 2;

Servo myServo1; //declaring a name for each of the four servos
Servo myServo2;
Servo myServo3;
Servo myServo4;

void setup() {
  // put your setup code here, to run once:
  myServo1.attach(servoPin1);
  myServo2.attach(servoPin2);
  myServo3.attach(servoPin3);
  myServo4.attach(servoPin4);

  pinMode(buttonPinPull1,INPUT); //the buttons are what is used to send the signal to servo
  pinMode(buttonPinRelease2,INPUT);
  digitalWrite(buttonPinPull1,HIGH);
  digitalWrite(buttonPinRelease2,HIGH);

  pinMode(buttonPinPull3,INPUT);
  pinMode(buttonPinRelease4,INPUT);
  digitalWrite(buttonPinPull3,HIGH);
  digitalWrite(buttonPinRelease4,HIGH);

  pinMode(buttonPinPull5,INPUT);
  pinMode(buttonPinRelease6,INPUT);
  digitalWrite(buttonPinPull5,HIGH);
  digitalWrite(buttonPinRelease6,HIGH);

  pinMode(buttonPinPull7,INPUT);
  pinMode(buttonPinRelease8,INPUT);
  digitalWrite(buttonPinPull7,HIGH);
  digitalWrite(buttonPinRelease8,HIGH);

  pinMode(servoPin1,OUTPUT); //the servo recieves data which is why it's an output
  pinMode(servoPin2,OUTPUT);
  pinMode(servoPin3,OUTPUT);
  pinMode(servoPin4,OUTPUT);
  //Serial.begin(9600);
}

void loop() {
  myServo1.detach(); //.detach() makes the servo stay at rest before any buttons are pressed
  myServo2.detach();
  myServo3.detach();
  myServo4.detach();
  
  if(digitalRead(buttonPinPull1) == 0) //will spin the servo in counter clockwise
  {
    myServo1.attach(13);
    myServo1.write(180);
    
  }
  if(digitalRead(buttonPinRelease2) == 0) //will spin the servo in clockwise
  {
    myServo1.attach(13);
    myServo1.write(0);
    
  }

  if(digitalRead(buttonPinPull3) == 0)
  {
    myServo2.attach(12);
    myServo2.write(180);
    
  }
  if(digitalRead(buttonPinRelease4) == 0)
  {
    myServo2.attach(12);
    myServo2.write(0);
    
  }

  if(digitalRead(buttonPinPull5) == 0)
  {
    myServo3.attach(11);
    myServo3.write(180);
    
  }
  if(digitalRead(buttonPinRelease6) == 0)
  {
    myServo3.attach(11);
    myServo3.write(0);
    
  }

  if(digitalRead(buttonPinPull7) == 0)
  {
    myServo4.attach(10);
    myServo4.write(180);
    
  }
  if(digitalRead(buttonPinRelease8) == 0)
  {
    myServo4.attach(10);
    myServo4.write(0);
    
  }
  delay(100);
}