Mechanical Hand

Cardboard mechanical hand for Purdue ECET380.

• Scissors
• Paper
• Marker/pen/pencil
• Chopsticks for wood
• Wires
• Wooden sticks
• Cardboard
• Filament (Monofiliment)
• Balsa Wood
• Hot glue
• Velcro
• Super glue
• Rubber Bands
• Arduino
• LEDs
• Push Buttons
• Zip ties(100 pack)

Make 2 marks on the paper that are parallel with each other and 7 cm apart

On those 2 points, take a coin and trace circles around them, connect the tops of the circles with lines.

Draw a straight line from the inside sides of each circle straight down to the horizontal line you just drew. Freehand a trapezoid on the bottom side that stems from the point that the lines just drawn intersect.

Color in as shown below and emphasize the center point of the other circle side. This will be your outline to cut out joint part shapes to ensure they fit together properly. 

Cut out this shape first. Also put a hole with the tip of the scissors or knife in the center of your rounded part. Make 10 of these.

Cut the same shape but add a hole in the center of the bottom horizontal line in the trapezoid as shown. Make 10 of these.

Draw another horizontal line as shown, approximately 1 cm above the bottom line. Follow by coloring that shape in.

Cut out the flowing shape that fills the uncolored portion. Make 20 of these.

Using the existing sketch, roughly draw these shapes off of the back and front of the body. Using the pre-existing circles to maintain the same radius. This will be the top and back parts of the fingers. Use the coin for the end of the finger radius.

Make a template piece and cut out 10 of each the top and the back part of the finger.

Glue two of the center joint pieces together.

Begin by gluing a 3/4 inch cut portion of a chopstick in the bottom hole. Glue one of the joint top pieces shown to this as well.

Take one of each of the parts shown and glue them together. Once the glue is dry, add glue to the bottom hole and middle and attach it to the existing side.

Add 2 holes to the bottom of one of the longer bottom finger pieces and glue them together.

Glue the following piece to the top and add two 3/4 inch chopstick pieces to the holes.

Create the other side that mates to this.

Attach the two finger sections together with a 1 inch long chopstick in the pivot hole.

Cut out a section to space the tip of the finger as shown. Lay out these three pieces to glue together.

Create the other side of the fingertip.

Add to the full finger assembly with a chopstick joint.

The thumb follows the same steps of creating the finger but only includes 2 sections.

Now that all of the fingers are done we can make the back of the hand at which they will attach to. Cut out the shape of the palm that would be needed to fit and equally space the fingers and thumb, also mess around with it to see if they will interfere with each other when bent.

Cut out the palm and make sure it is sized with the back of the hand and has the space for the thumb to be included. The thumb will be off to the side compared to the other fingers, keep this in mind when placing them.

Once the hand pieces are cut out we can attach the fingers to the main hand. This means you have to cut out and make the mounting points that have chopstick pins in the holes. When the fingers are all attached to the joints on the back of the hand we can then add the palm.

Now we can attach the sting to the tip of the fingers and run it through the hand back to the user. Cut 5, 1 foot strands of 10 pound fishing line and glue one end to the tip of each finger. Push it under the created pin guides and down through the bottom of the hand.

Cut out the sides of the hand that will be roughly 1 inch, this will create space for the microcontroller as well as the filament that controls the fingers to move in. Glue the palm pieces together. Also include the guide for the lines to go into the user hand placement.

Simply make a hand sized cutout and make cardboard rings on the fingertips. The filament will attach to the end of the fingers via glue. At this point tension the filiment correctly and glue to the inside of the hand.

Create the box that the user will have their hand in the glove in. Put 4 holes in the top of the box and feed the filament through. Tie to the fingertips of the rubber dipped glove.

Make the handle that the user will grab onto and mount the breadboard on top of it so that the users fingers can press the push buttons. It will just be a single piece of cardboard that runs over the user's palm.

Add 5 buttons evenly spaced on the breadboard. Add a resistor to the bottom first pin of each push button going to the red power bus on the bread board

Grab your LED and plug each end to a Femal header of the male to female wires provided, ensure you write down which wire has the longer lead of the LED. The longer lead wire of the wire must be connected to the push buttons bottom  second pin while the shorter lead of the LED must connect to the blue ground bus on the Bread board. Connect the GND pin of your arduino to the Blue ground bus of your bread board

Connect the 5V pin of your arduino to the 5 V bus of yourbread board (ensure this is the same bottom hald of your bread board where your Resistors lead to). Connect your ardunio to the Portable powersource and power on.

Download the Arduino IDE Envirement from https://support.arduino.cc/hc/en-us/articles/360019833020-Download-and-install-Arduino-IDE. Create a new sketch and copy the provided code into the IDE. Plug in your ATMEGA 2560 to your computer, then on the upper left side of the screen verify and upload the code. Once this has been successful unplug your arduino

Add the lights to stick out of the back of the hand, one for each knuckle. Place the breadboard on the top of the inside handle and the arduino inside the palm under the filiment.

Attach the microcontroller to the outside of the user hand box and run the wires through the front of the user control box.

Verify that everything functions properly and enjoy. If you want some more aesthetic you can paint and decorate however you wish.