Bionic limbs are replacements for normal limbs that may have been lost. Bionic limbs use modern technology to help the human regain movement again with an artificial/mechanical limb. There are numerous reasons for losing limbs; tragic injuries, cancer, defects at birth. For anyone who loses a limb, life is very different. Not having a natural set of limbs impacts peoples lives incredibly strongly. Thankfully, bionic limbs were the solution that was invented to help/ Bionic technology is constantly being improved and innovated for the better, now working with AI (artificial intelligence), which is a huge addition to bionic sciences.
This project was focused on the creation and building process of bionic limbs. Creating the singular bionic finger using Arduinos gave an insight to which ways bionic limbs can move.
Components needed
- A 3D printed finger
- A sheet of transparent overhead plastic
- Fisherman's wire
- Ardunio board and laptop/computer
- A USB cable
- An SG90 microserver
- A 2.2" Flex Sensor
- Batteries + battery case
- A glove to attatch the Flex Sensor to
- A wooden board OR any hard, sturdy surface
- A hot glue gun
How to assemble
- Cut out strips of the plastic and fold it up so that it fits flexibly between the gaps in the 3D printed finger. Use hot glue to secure it. Make sure the length is that of a normal finger.
- Use the nylon wire and thread it through the holes in the center of the seperate parts of the finger. Secure the wire to the tip of the finger with hot glue as well.
- Tie the other end of the wire to the furthest hole in the microservo. Secure with hot glue if needed.
- Attach the wires from the microservo to the digital pins in your Arduino board. The number will change depending on the the number of the pin in your code, but make sure they are the same. The brown wire has to attach to G, the red wire has to attach to V, and the yellow wire has to attach to S, if you're using the nanoboard.
- Attach the wires from the flex sensor to the analog pins in your Arduino board. Again, the number will change depending on the the number of the pin in your code, but make sure they are the same. It doesn't matter which colour of wire is connected to which, but they have to be attached to G and S.
- Use the USB cord to connect your board to your laptop. Code will be provided in the next section as well as an explanation.
- Attach the finger to the edge of the wooden board using a hot glue gun. Once that has set, place the microservo on the board so that it gets rid of as much slack as possible, but still allows the finger to return to a straight position. Secure the microservo on the wooden board.
- After you have coded and calibrated, use a hot glue gun to attach the flex sensor to the glove.
- Prepare the batteries and attach it to the Arduino board.
- Once you are happy that the flex sensor is properly calibrated, attach the rest of your compenents (apart from the glove) to your wooden board.
The code - just copy and paste!
//Include Servo library
#include
Servo myservo; // create servo object to control a servo
void setup() {
myservo.attach(6); // attaches the servo on pin 6 to the servo object
// Configure flex sensor pin
pinMode(A0, INPUT_PULLUP);
Serial.begin(9600);
}
void loop() {
int flexSensor = analogRead(A0);
/*Values from sensor are about 380 -> 550;
we need to convert this to about 0 -> 170
since my finger is too short to be affected
when the servo moves 180 degrees*/
int angle = (flexSensor - 380) / 1;
Serial.println(angle);
myservo.write(angle); // set servo position
}
What It will do
This code will allow the finger to move using the flex sensor, and will make it easy to move at the user's will.