Automatic Food Slicer

This device slices fruit that is placed on it. There is a DC motor that has a knife attached to it which is made from two pieces of cardboard with razor blades between them. A servo motor with an “arm” attached to it is used to push the food towards the knife. There is also a button that is extended by a 1” piece of a popsicle stick that is accessible and can be pushed to speed up the device. A pressure sensor on the top left of the device is used to activate it. The Arduino/breadboard and most wires are kept within a cardboard box to make the device more presentable. When the pressure sensor picks up any amount of force, an if-statement in the code begins to run, activating the device. An arm attached to a servo motor begins by rotating to the set angle (angle is initiated at 0 degrees), followed by a DC motor spinning counter-clockwise for three seconds and then clockwise for three seconds. This DC motor has the knife attached to it so that as it spins the knife is either cutting down on the fruit or coming up. After each cycle, as long as there is still pressure applied on the sensor, the angle of the servo will be incremented, pushing the food further along its path. If the user finds this to be too slow or that the pieces are too thin, there is a button that is easily accessible that will cause the device to move faster and slice thicker pieces. Using an if-statement, if the button is pressed the DC motor spins for less time and there are smaller pauses between each iteration of the code. The initial angle is also incremented by twenty degrees instead of ten, when this button is pushed, resulting in thicker slices of fruit being produced.

Quantity: 1

Price: $3.23

Total Cost: $3.23

Asin: B0051XQEGK

Quantity: 6

Price: $0.01

Asin: B098T17GBX

Quantity: 1 

Price: $5.19

Total Cost: $5.19

ASIN ‏ : ‎ B08BTR93YV

Quantity: 1

Price: $1.11

ASIN ‏ : ‎ B0868QV9D6

Quantity: ½  (Order was split)

Price: $3.97

Quantity: 1

Price: $0.89

Asin: B0854Q9WV2

Popsicle Sticks

Quantity: 6

Price: $0.03

Arduino 

Part Number: 1050-1024-ND

Vendor: Digi -key

Price: $20.90

Quantity: 1

Breadboard

Part Number: 79X3922

Vendor: Newark

Price: $2.71

Quantity: 1

Mini DC motor 1.5-12VDC 1350 Rpm

Part Number: 2209094

Vendor: Jameco

Price: $1.25

Quantity: 1

Micro Servo Positional Motor

Part Number: SER0006

Vendor: Dfrobot

Price: $3.30

Quantity: 1

Tactile Switch Push Button

Part Number: 155380

Vendor: Jameco

Price: $0.35

Quantity: 1

100k Ohm Resistor 

Part Number: 100kQBK-ND

Vendor: Digi-key

Price: $0.01

Quantity: 2

Wire Kit

ASIN: B07PQKNQ22

Vendor: Amazon: Austor

Price: 2.17

Quantity: 1

3-Wire Extension

Part Number: 1568-1930-ND

Vendor: Digi-Key

Price: $1.35

Quantity: 1

Cut out a 6.5” x 11” rectangle from one of the cardboard boxes, this is the base

On another cardboard box (call this one Box 1):

Cut off the edges on the side that folds on top and acts as the top part of the box so it looks like Step 3, item 1

On the right face of the box: cut out a 1cm x 1cm hole 1 inch from the top, ¾” from the side. (hole 1)

On the left face of the box: cut out a 1cm x 1cm hole 1 inch from the top, ¾” from the side (hole 2) Cut out a 1 ½” cm x 1 ½” cm hole 2 inches from the bottom and ¾” from either side (hole 3), and another 1 ½” cm x 1 ½” cm hole 3 inches from the bottom but ⅝” from the left side (hole 4).

On the front: cut out a 1cm x ½ cm hole 1 ½” from the left side and 2” from the top (hole 5). cut out a 1cm x 1cm hole 3” from the right side and 1 ½” from the top (hole 6).

Tape the breadboard to the Arduino such that the breadboard is on the side closest to the USB port, but not the same side as the USB port (perpendicular side) then tape this inside of Box 1 such that the plug for the USB and the other outlet corresponds with hole 3 and hole 4, respectively.

On the back face of box 1, Tape the battery pack to the bottom left corner of the box, make sure that the on/off switch is facing out and is accessible.

Cut a .75” x 3 popsicle stick (stick 1), center this on the servo motor, and tape it onto it. Cut a .75” x 2.75” rectangle from another popsicle stick (stick 2). Cut a .75” x 3.5” third popsicle stick (stick 3), Step 3, item 4

On the right side of stick 1, tape stick 2 on it so that it is only extending out in one direction. Tape stick 3 so that its ends match up with the ends of stick 1 and stick 2. 

Cut out a 4” x 1” rectangle from the cardboard boxes and bend it into an L-shape with the crease happening 1” from one of the sides. Use tape to make sure it stays bent. Step 3, item 2

Cut a small hole that is 2cm wide and as thin as you can make it 1 ½” on the long side of the L-shaped cardboard.

At the point where stick 2 and stick 3 meet, wedge this part into the hole made in the part above, and with glue or tape securely attach the cardboard to the popsicle sticks.

From the spare cardboard boxes, cut out two rectangles that are 8” x ¾” and cut out the bottom right corner from each so that it looks like Step 3, item 5.

Starting at the top, place a blade between these rectangles such that the blade tip is even with the top. Either glue or tape this blade securely between the cardboard pieces.

Centered at approximately ⅜” above the bottom, make a tiny hole such that the DC motor’s metal rod can be attached through the incision and that the blade can be glued securely to the rod.

From the remaining popsicle sticks, cut out two small rectangles that are 1” x ⅛” and tape two together. Glue this onto the button so as to extend the button by an inch. Connect the button to the breadboard such that this inch extension comes out of hole 6

Place the cardboard box with the Arduino on the top right part of the base, at a 45-degree angle. Tape/Glue the box to the base

Tape/glue the DC motor to the base with the blade part facing away from the box. Connect the wires to the breadboard through hole 1. The wires can be extended by intertwining the metal tips of two wires and wrapping them in electrical tape

The servo motor and arm should be attached to the bottom right part of the base, with either glue or tape. Using a three-wire extension and three wires connect the wires to the breadboard through-hole 2

The pressure sensor should be connected to wires by intertwining them together and wrapping them in electrical tape, and they should be connected to the Arduino through hole 5. Tape/glue the pressure sensor to the top left corner of the base where it will be easy to access.

With the remaining boxes, cut out five small rectangles that are 1.75” x 3” and tape them together. Glue these onto the base under where the arm will push the fruit but before the blade. This will raise the fruit so that the arm will push it and not just go over it. Step 3, item 3.

Glue the Aluminum foil to the exposed areas of the base as well as the part of the arm that makes contact with the food. (Optional) You can also wrap all of the exposed cardboard/wires with aluminum foil to make the device look better.

The following code was uploaded to the Arduino

Item 1: Box 1

Item 2: L-shaped arm

Item 3: Raised Surface

Item 4: Popsicle sticks

Item 5: knife

(The pictures are available to download)

Drawn circuit diagram