Robotic Hand

Today we are going to learn how to build a working robotic hand for math and computer tech class.

The supplies you need to assemble the robot hand is:

• Styrofoam
• Professional(optional) Fishing line
• Glue gun
• Marker
• Elastic bands
• exacto knife
• Arduino uno
• Arduino nano
• paper clips
• ruler
• Sander
• wires
• plyers
• needle
• Data USB cable

For the two codes we used for math, this one is to find the total volume of the rectangular prism that we are about to make in the next step and to do this you need to know the volume of a rectangular prism, truncated cylinder, and hemisphere. Once you had figured that out you would then you would start the code off with import math because you will be needing pi to find the truncated cylinder and hemisphere, then you would need find the cylinder with hemisphere and to that you would add the volume that you had already made for the truncated cylinder and the hemisphere.

After you would put how to find the total volume which is rectangular prism subtract the cylinder with hemisphere.

For the second code that we used for math, this one is to find the volume for the three section of one of the fingers and to find the total volume of the whole finger (after being sanded).First you would need to start the code off with again import math because you will need to find pi for the truncated cylinders and you would need to have measured the diameter, height1 and height2 of the three sections of the cut out finger. and apply that to the code (shown in pictures). After you would need to know the volume of a truncated cylinder and write it three times for each finger and you should probably number the fingers, so that you have the top of the finger as 1, the middle part of the finger as 2 and so on.

Then you would need to find the total volume of the full finger, so then you would put the next line as them being added all up.

Once the two codes for math is finished, you have to grab most of your materials to start on the actual build for the hand.

Since we are starting with the fingers you would need to get the Styrofoam, a pen, the exacto knife, a ruler, and most importantly the model for the hand.

Next you would put the one of the models fingers and trace a rough sketch on the styrofoam to see how long or short you need to cut it, into a rectangular prism and make sure to cut it a little bit bigger than the actual finger. After you grab the exacto knife and use it to cut a rectangular prism with the rough sketch that you had made before hand.

Then you would measure the rectangular prism by measuring the length, width, height of it by using a ruler.

Lastly you would continue doing the same steps for each of the fingers.

First the materials you will need is a sander, the rectangular prisms you cut in the second step, and again most importantly the models hand.

After grabbing the materials you need to sand the fingers in a upward motion to make a cylinder which means sand to the top of finger to resemble a semi circle as the tip of the finger. As you are sanding the finger to look more like a real finger use the models hands to see if you are close to resembling the same finger as their own.

Once you think the finger looks good enough/ looks more like the actual models finger you would measure the cylinder by measuring the diameter then divide by 2 to get the radius and lastly the height.

Do that for each finger to complete the look.

Now that you have sanded all the fingers to resemble the models fingers you would then need to cut the fingers into 3 pieces per finger using your finger joints and to do this task you would follow the marks on your models fingers.

There is a specific way to cut it to make the fingers curl, what you have to do it cut the fingers on a angle in order for it to curl. (shown in pictures) And when you do the thumb you only need to cut it into two instead of three.

To make the palm and forearm you would need to grab your styrofoam and make sure that it is a big piece and has a long length to it. Then you would grab your models hand and place their palm close to the top of the styrofoam.

Then trace the palm and the forearm and make sure it is long enough to put your servos on.

Next you would need to grab the fishing line, the needle, scissors, the paper clips, plyers, the palm and forearm, and the 3 pieces for each finger (I would recommended to go one finger at a time).

Once you have gathered the materials you need to put one of the fingers that you chose next to the forearm and palm and grab the fishing line to measure it across and make sure you make it longer than the actual length of the forearm and palm, so you can sew it through the fingers into the hand.

After cut the length of the fishing line to how you think would be enough for you to sew it through and have an extra length too.

Now that you have gotten the length of the fishing line, you would grab the needle and put it through the fishing line and tie one end of the line.

Then you would grab the top section of the finger that you chose and poke the needle into the tip/top of the finger and let the fishing line go through the top section of the finger and as you are pushing the needle through one end of the string, it might get stuck mid-way so to find it pull one string and see if it moves the finger and if it doesn't then that is the one that needs to be pulled all the way through.

Then you do sew it through the top section of one finger, and then you do each section for the finger (make sure to sew it through the top of the finger section) and then tie the other end of the line.

Then you do sew it through the top section of one finger, and then you do each section for the finger (make sure to sew it through the top of the finger section) and then tie the other end of the line.

After you have sewed all 3 sections of a finger into the fishing line, you would then grab the palm and forearm and since you had marked the places where you want the fingers to go in you would take the finger that is sewed in together with the needle and poke it through the palm in a slanted motion so that it is turning upwards, you need to be able to see the needle coming out.

Then pull the string that is on the needles side through and if it gets stuck again mid-way you would do the same thing I said before.

Lastly, to keep the fingers tight you would need to get the paperclips and push one part of the inside of the paperclip so one half sticks out, then grab the plyers cut one side of it so its in a arch. Do that multiple times so then you can put it all down on one string for one of the fingers (make sure to pull tightly while you put the paperclips in it, but not too tight

Finally, you would do that for each one of the fingers.

First you need to grab the elastic bands, glue gun with glue sticks for it, the hand (with the fingers attached/sewed in). Also it would be better to start off with one finger at a time.

You need to make the fingers line up straight for the tech code to work in general, so you would flip around the hand so that the fingers are at the back.

Then you would need to straighten the fingers out and make sure that the glue gun is ready to be used.

After you would cut the elastics into small pieces but enough for it to reach to one section of the finger, then grab the glue gun and make two small dots on where you are going to place the elastic bands.

Next you would do the same for the next section of the finger and most importantly use more than one elastic piece for each section.

The code for tech class is used to get the servos to turn to an 180 degrees in order for the fingers to work. We had used this code from our teacher.

#include <Servo.h>


Servo thumb;
Servo index;
Servo middle;
Servo ring;
Servo pinky;


void setup()
{
  thumb.attach(3);
  index.attach(5);
  middle.attach(6);
  ring.attach(9);
  pinky.attach(10);
}
 void loop ()
 {
   start();
   delay(1000);
   stop();
 
   griping();
   delay(1000);
   stop();
   
   rock();
   delay(1000);
   stop();
   
   pinch();
   delay(1000);
   stop();
   
   pointing();
   delay(4000);
   stop();
   
   thumbup();
   delay(5000);
   stop();
   
   peace();
   delay(4000);
   stop();
   
   shaka();
   delay(4000);
   stop();
   
   gun();
   delay(1000);
   stop();
   delay(100000);
 
 }
void warmup()
{
   thumb.write(90);
   delay(1000);
   index.write(90);
   delay(1000);
   middle.write(90);
   delay(1000);
   ring.write(90);
   delay(1000);
   pinky.write(90);
   delay(1000);
}


 void pointing()
 {
  thumb.write(45);
  index.write(0);
  middle.write(90);
  ring.write(90);
  pinky.write(90);
 }
 void pinch()
 {
  thumb.write(0);
  index.write(45);
  middle.write(90);
  ring.write(90);
  pinky.write(90);
  delay(1000);
  index.write(45);
  delay(500);
  index.write(0);
  delay(500);
     index.write(45);
  delay(500);
  index.write(0);
  delay(500);


     index.write(45);
  delay(500);
  index.write(0);
  delay(500);


     index.write(45);
  delay(500);
  index.write(0);
  delay(500);
     index.write(45);
  delay(500);


 }
void thumbup ()
{
  thumb.write(0);
  middle.write(90);
  ring.write(90);
  pinky.write(90);
  index.write(90);
}


void peace()
{
    thumb.write(45);
  index.write(0);
  middle.write(0);
  ring.write(90);
  pinky.write(90);
}
void shaka()
{
  thumb.write(0);
  index.write(90);
  middle.write(90);
  ring.write(90);
  pinky.write(0);
}
void start()
 {
   delay(100);
   pinky.write(90);
   delay(100);
   ring.write(90);
   delay(100);
   middle.write(90);
   delay(100);
   index.write(90);
   delay(100);
   thumb.write(90);
 }
void griping()
{
  thumb.write(0);
  index.write(45);
  middle.write(45);
  ring.write(45);
  pinky.write(45);
  delay(1000);
 thumb.write(0);
  index.write(0);
  middle.write(0);
  ring.write(0);
  pinky.write(0);
  delay(1000);
 thumb.write(0);
  index.write(45);
  middle.write(45);
  ring.write(45);
  pinky.write(45);
  delay(1000);
 thumb.write(0);
  index.write(0);
  middle.write(0);
  ring.write(0);
  pinky.write(0);
  delay(1000);
 thumb.write(0);
  index.write(45);
  middle.write(45);
  ring.write(45);
  pinky.write(45);
  delay(1000);
 thumb.write(0);
  index.write(0);
  middle.write(0);
  ring.write(0);
  pinky.write(0);
  delay(1000);
thumb.write(0);
  index.write(45);
  middle.write(45);
  ring.write(45);
  pinky.write(45);
  delay(1000);


}
void rock()
{
  thumb.write(0);
  index.write(0);
  middle.write(90);
  ring.write(90);
  pinky.write(0);


}


void gun()
{
  thumb.write(0);
  index.write(0);
  middle.write(0);
  ring.write(90);
  pinky.write(90);
}


void stop()
{
  thumb.write(0);
  index.write(0);
  middle.write(0);
  ring.write(0);
  pinky.write(0);
}
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To wire the Arduino you would need to get the Arduino Uno, the Arduino Nano, the data USB cable, the hand, the hot glue gun, the wires, and the exacto knife.

To start you would have uploaded the code by putting the data USB cable into whatever you had made the code into mostly likely a laptop and put the other end into the Arduino Nano which then you would press upload onto the actual code that you had made and it would transfer into the Arduino Nano as it should be also connected into the Arduino Uno (make sure that the Arduino Nano shows a red dot which means it is on). Then you would grab the wires and place them into the spots you had directed them to from the previous tech class code and once it is connected the servos should move (example video).

If it does work then you would start by cutting out a small hole (like a small dent) in the hand to place the servos into, once you have then grab a hot glue gun and use it to place the servo into the hand. Then grab the string for the specific finger that you are choosing and since your servo should have an arm on it with holes, you would then put the strings through at least two holes and tighten it/pull on it but not too hard to the point where you pull the string into the finger and have to re sew it in (recommended to hot glue the string thats coming from the top of the finger that you are using so that doesn't happen).

Finally you would turn back on the Arduino by putting one end into the laptop and the other back in the Arduino nano the n your fingers should move on its own (and if it doesn't try pulling the leftover string that you have and if it moves that means you should tighten your string to the servos more).

Now your fingers should be moving like the example video and your finished hand should look like this (with more servos onto it ((5)).