Rube Goldberg Gumball Vending Machine

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Hello there! In this informative step-by-step guide, I will take you through the procedure done by me and my team in order to develop an effective and fun Rube Goldberg Gumball Vending Machine. Whether you're reading this to pass some leisure time or are attempting to build a Vending Machine of your own, I hope this guide leaves you very informed and that executing this project was as much fun for you as it was for me and my team!

Step 1: Gathering a Team

The first order of business for any team is to make sure everyone is assigned a part in the project. The following is how our team was organized:

  • Stella Bagno:

.Team Leader

.Math Specialist

.Contributor to building the machine

  • Andrea Castillo:

.Video Producer

.Voice-over narrator

.Contributor to building the machine

  • Kiara Vargas:

.Painter

.Author of this awesome booklet

.CAD specialist

.Contributor to building the machine

Step 2: Bill of Materials

The following materials is what my team and I used to build our vending machine (keep in mind that these were the materials that worked for us and your machine may have/not have some materials listed below):

  • Bumper switch (1)
  • LED lights (8 ft chord)
  • Light switch
  • Spring
  • Yarn string (8 feet spool but not all of this would be used)
  • Scrap cardboard pieces
  • Duct tape
  • Limit switch (1)
  • Plastic fish bowl (we got ours at the dollar store)
  • Small basket
  • Lever (1)
  • Thumb tacks (pack of 20)
  • Plastic Funnel
  • 1 yard of cotton fabric
  • Wood planks (sizes vary)
  • Gumballs
  • A small pulley
  • Plastic tubes (made out of scrap plastic pieces with varying sizes)
  • Motors (2)
  • Hot glue gun
  • Hot glue sticks
  • Acrylic paint
  • Paint brushes
  • X-acto knife
  • Scissors
  • Metal rods measuring 7 inches (4)
  • Small metal hook
  • Saw
  • A small triangular object
  • Sand (226.8 grams)
  • Scale (newtons)

Step 3: Procedure and Design

Procedure:

  1. Buy and gather the materials at a clear work space
  2. Make frame of the vending machine with cardboard and hot glue (be sure to add snack dispenser on the bottom right and a coin slot on the right side piece)
  3. (optional step) paint the back panel.
  4. Make spiral out of plastic scrap pieces and attach to frame
  5. Make an inclined plane out of a wood plank and attach to machine according to diagram above (repeat another 3 times)
  6. Attach tubes corresponding to diagram
  7. Attach funnel
  8. Place thumb tacks above the funnel to guide the gumball
  9. Attach gears one and two
  10. Attach pulley
  11. Place lever/fulcrum in the corresponding to diagram
  12. Wire the motor and attach it to the rotating disk for the spiral
  13. (optional step) line the frame with LED lights
  14. Fill fish bowl with gumballs
  15. Attach bowl to the corresponding spot

Step 4: Switch-Spring Mechanism

Materials used:

  • Cardboard
  • Scissors/ x-acto knife
  • Light switch
  • String
  • Spring
  • Hot glue

Build Instructions:

  1. Cut cardboard pieces to construct the box (one piece measuring 10.16cm x 17.78cm,one piece measuring 5.08 cm x 12.7cm, two pieces measuring 5.08cm x 17.78cm, and two pieces measuring 1.27cm x 17.78cm).
  2. Cut two pieces of string measuring 20.32cm.
  3. Punch a tiny hole on each side of(one big enough to loop the string through) the 5.08 cm x 12.7 cm piece (1.27 cm away from the ends).
  4. Loop one string through each hole.
  5. Make a box around the light switch, attaching the pieces with hot glue (the 10.16cm x 17.78cm piece on the back, 5.08cm x 17.78cm on the sides, and the 1.27cm x 17.78cm pieces on the front).
  6. Attach the spring 2.54cm above the box-switch mechanism.
  7. Tie the stringed cardboard piece to the spring and make sure the piece stays right above the light switch.
  8. Attach the switch-spring to its place with hot glue.

Calculation:

  • F(force):

F_1(weight of the box)

F_2 (weight of the spring)

F_3 (weight of the box plus a quarter)

  • m (mass)
  • a (acceleration)
  • g (gravity)

F= m*a

F = 3 newtons and F_1 = 3 newtons

F_3 = F_2 + 1 newton = 4 newtons

Since F_3 overpowers F_1, the Switch-Spring mechanism will work with the activation of a quarter.

Step 5: Rotating Dish Plate Mechanism

Materials needed:

  • X-acto knife
  • Hot glue
  • Cardboard

Building Instructions:

  1. Cut two cardboard circles with a radius of 2".
  2. Cut a cardboard ring with a radius of 2.2"
  3. On one circle, cut a rectangular hole measuring 1" x 1", 0.5' away from the end of the piece.
  4. On the ring and the other circle, cut an opening 60 degrees wide about the center.
  5. Glue the ring to the circle, alining the openings.
  6. Place the circle with the ring on top of the other circle.
  7. Attach the the plate in its place with hot glue.

Calculations:

0/t = 120 degrees / 3 seconds = -40 (or clockwise 40) degrees per second

The dish makes one full rotation every 9 seconds.

Step 6: Inclined Plane (Object 3)

Materials needed:

  • A saw (the type may vary depending on how thick your wood is)
  • A wood plank

Building Instructions:

  1. Cut the wood to measure 30 cm.
  2. Attach the plane to its place.

Calculations:

vf^2 = 2as

vf^2 = 2(9.8 m/s^2 sin 70 degrees)(0.3 meters)

vf^2 = 5.5 m^2/s^2

vf = 2.35 m/s

The gumball will be going at a velocity of 2.35 meters per second.

Step 7: Tube (Object 4)

Materials needed:

  • Cardboard tube pieces
  • Hot glue
  • Scissors

Building Instructions:

  1. Make the tube shape out of cardboard tubes, putting the pieces together with hot glue.
  2. Attach the tube to its place with hot glue.

Calculations:

vf^2 = 2as

vf^2 = 2(9.8 m/s) (0.08)

vf^2 = 1.57 m^2/s^2

When the gumball is free-falling, it is going at 1.25 meters per second

vf^2 = 2.05

vf^2 = 2(9.8 m/s^2 sin 90 degrees) (0.02)

vf^2 = 0.2 m^2/s^2

When the gumball is going at a curve, it is going 0.45 meters per second

Step 8: Funnel Mechanism

Materials needed:

  • Plastic funnel
  • Hot glue

Building instructions:

1. Attach the funnel in its correct place.

Calculations:

  • 0/t = 360 degrees/ 3 seconds = 120 degrees per second
  • 0/t = 360 degrees/ 2 seconds = 180 degrees per second
  • 0/t = 360 degrees/ 1 second = 360 degrees per second

Step 9: Gears

Materials needed:

  • 1 yard of fabric
  • Metal rod
  • Cardboard pieces
  • Hot glue

Building instructions:

  1. Place the metal rods corresponding to its placement on the diagram.
  2. Measure how much fabric will be needed for it to circle around the rods, keeping it slightly loose.
  3. Once measured, cut the fabric to the correct measurement for each gear,
  4. Make 64 1" x 1.5" rectangular cardboard pieces.
  5. Glue the pieces onto the the fabrics accordingly.
  6. Glue the ends of the fabric pieces when the cardboard pieces are dried.
  7. Place the fabrics gears onto the metal rods.

Calculation:

Gear 2 is 1.5 times faster than gear

5 m/s*1.5 = 3.5 m/s

If gear 1 spins at 5 meters per second, gear 2 spins at 3.5 meters per second.

Step 10: Inclined Plane (Object 15)

Materials needed:

  • A saw (the type may vary depending on how thick your wood is)
  • A wood plank

Building Instructions:

  1. Cut the wood to measure 8 cm.
  2. Attach the plane to its place.

Calculations:

vf^2 = 2as

vf^2 = 2(9.8 m/s^2 sin 30 degrees)(0.08 meters)

vf^2 = 0.78 m^2/s^2

vf = 0.88 m/s

The gumball will be going at 0.88 meters per second.

Step 11: Lever/Fulcrum

Material needed:

  • Wood plank
  • Triangular object
  • Saw
  • Cardboard
  • Sand
  • Hot glue
  • A scale (newtons)

Building instructions:

  1. Cut wood plank measure 6 cm.
  2. Make a box of 1 x 1 x 1 without closing off one side (making the attachments with hot glue).
  3. Fill the hollow box with sand. Make sure it weighs 10 newtons by checking with the scale.
  4. Close off the open side of the box with another cardboard piece and hot glue.
  5. Place the triangular object in its correct place.
  6. Place wood plank on top of triangular object.
  7. Place box in its correct place.

Calculations:

Weight of the box = 10 newtons

Weight of the gumball = 2 newtons

Upward force: 2(10) newtons = 20 newtons

20 newtons - 2 newtons = 18 newtons.

The total upward force required is 18 newtons.

Step 12: Pulley

Materials needed:

  • Pulley
  • Basket
  • Weight
  • Small hook

Building instructions:

  1. Attach the small hook to the "roof" of the vending machine.
  2. Attach the pulley to the hook.
  3. Attach the weight at the longer end.
  4. Attach the basket at the shorter end.

Calculations:

F_1 = weight (5 newtons)

F_2 = weight of the basket (4 newtons)

F_3 = weight of gumball (2 newtons)

F_2 + F_3 is enough to overcome F_1

Step 13: Spiral

Materials:
  • Cardboard tube pieces
  • Hot glue
  • Scissors

Building Instructions:

  1. Make the spiral shape out of cardboard tubes, putting the pieces together with hot glue.
  2. Attach the tube to its place with hot glue.

Calculations:

0/t = 360 degrees / 2 seconds = 180 degrees per second

The gumball will rotate at an angle of 180 degrees per second.

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