3D Printed Robotic Hand

A 3D printed hand that mimics human hand movements through flex sensor readings on a glove. A glove that is worn by the user is used to control the movements on the hand.

Engineer:

Parth

Area of Interest:

Electrical Engineering

School:

Cupertino High School

Grade:

Rising Senior

Schematic Diagram for the Final Product.

schematic-for-robotic-hand

Final Presentation/Reflection

In retrospect this project was tough but extremely rewarding. I refined the knowledge I already had(Computer Science, Electrical Engineering), and learned a multitude of new skills(Mechanical Engineering, sewing). Regardless, I realized that the world is a complex place, and that I have so much more to learn. My arm is a perfect starting level project because I scraped the basics of most engineering fields. My next project idea would be something more complex, such as an exo-arm, which requires a deeper knowledge of Mechanical, Electrical, and programming concepts. Additionally, it was interesting building this hand because it taught me that theory often times differs from reality, and components that look perfect may not function well in real life.

Milestone#3: Getting the final project completed.

My third milestone was to get the final project completed and functioning. The final project consists of the arm with servos and fishing line. Each finger on the hand has two fishing line pieces running through it. One of the lines pulls the finger forward and the other pulls it backwards. The servos move according to the amount that the corresponding flex sensor is flexed. One of my biggest challenges in completing this milestone was getting the fishing line crimped onto the servos. The crimp tubes I was using were very small and I had to spent significant amounts of time adjusting them to make the fishing line fit through them.

Milestone#2: Getting the Flex sensor circuit onto the glove and PCB.

My second milestone was getting the entire flex sensor circuit onto the PCB and getting that onto the hand. I realized that the arm piece can only hold four servos, so I attached 4 flex sensors to all the fingers except the thumb. The thumb will move when the pointer finger moves. I used generous amounts of solder to connect one end of the 15k resistors to ground. I connected the other end of the resistors to the signal input wires. Those input wires were then connected to the ground wires that connect directly to the flex sensors. I also used solder to connect the power wires together to connect them onto the 5V pin on the Arduino.  The other end of the power wires go straight to the power side of the flex sensors.

Milestone#1: Getting the Servos and Flex sensors Working.

My first milestone was getting the Servos and Flex sensors working together. I used a breadboard to test out my circuit before soldering it onto a PCB. Additionally, the flex sensor is essentially a variable resistor that changes resistance as you bend it. This is connect in series with another resistor to create a voltage divider. As the resistance of the flex sensor increases, the voltage drop over the flex sensor increases, giving a lower voltage input into the Arduino. The analog voltage input can be mapped to a certain number of degrees(0 to 180) that the servo can move to.

Starter Project: Terror-Min

My starter project is a Terror-min circuit kit that makes a buzzing noise when it is exposed to low light environments. It was created using a Sparkfun kit, and it contained a simple PCB, a couple transistors(NPN and PNP), a capacitor, a resistor, and a buzzer. Batteries were used to power the circuit and a switch was used to turn the circuit on and off accordingly. One hindrance I encountered was with the description that the kit provided. It stated that the buzzer should “scream” when it was exposed to a lot of light, however, after checking the circuit multiple times it was apparent that the kit provided buzzes only when exposed to low amounts of light. Overall I thought this was an interesting project because I ended up learning a lot about how electricity, voltage, and circuits play a huge role in the everyday devices we use such as phones and laptops.
Showing 2 comments
  • Rishabh Shah
    Reply

    Wonderful project, fellow HSIB!

  • Kumaran Akilan
    Reply

    Hopefully you can put that hand to great use!

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