Tatiana P.

My name is Tatiana, and I am rising senior at The Chapin School. This summer my intensive project was a 3D printed gesture control hand and my starter project was the mini pov 4. Through these projects I challenged myself to learn and problem solve independently.

Engineer
Tatiana P.
Areas of Interest
Mechanical Engineering

 

Biomedical Engineering

 

Chemical Engineering

School
The Chapin School
Grade
Incoming Senior

Reflection

Through my experience at BlueStamp I have learned a lot about myself as an engineer. Coming into this program I was completely sure that I wanted to study biomedical engineering in college, but after working with mechanical and electrical engineering on my project, I have found that I do not want to go into college with such a narrow field of study. Now I am looking forward to being able to explore different types of engineering and not having to specify my studies right away. I have really enjoyed the BlueStamp environment where even if we all had different project the students were willing to help each other and where the instructors set you in the right direction but encouraged you to find out the answers for yourself. I was able to problem solve and think independently. I wanted to push myself to persevere through these challenges, so that when I was able to solve problems in my project I had a greater feeling of accomplishment. My greatest challenge I faced while at BlueStamp was my project not working the day of my presentation. One of the servos stopped working because I did not have a voltage regulator in my circuit, and it was overloaded. That day I had to figure out what a voltage regulator is and how to use it in a circuit. When I presented and my project finally worked I was so proud that I was able to overcome this challenge. Another challenge I faced was trying to implement NRFs in the circuit. I was able to complete the circuitry and code but unfortunately there was not enough time to debug it and figure out why the NRF attached to the glove was not transmitting. I hope to continue to work on the NRFs after BlueStamp is over. It is hard to believe that my time at BlueStamp is coming to an end, but now I am excited for all that I will be able accomplish with engineering in the future.

Final Project

For my final milestone I have added a voltage regulator to the circuit. A voltage regulator lowers the voltage input from the battery so that the servos are not overloaded. Now instead of 9.6V going to the servos the voltage regulator changes the voltage to 5V. This step is important to my project because without it my servos could be fried and stop working. I did not have the part until yesterday and one of my servos stopped working so I had to replace it and put in the voltage regulator. I had to figure out how to add the voltage regulator into my circuit with out the help of a specific schematic. I had to research this voltage regulator and find out how it works in a circuit to find out how I should implement it in mine. First I put the voltage regulator in a breadboard to make sure that the circuit would work. I checked with my instructors as well before transferring the voltage regulator to a PCB board. The voltage regulator requires to capacitor in its circuit as well as a heat sync so that it does not overheat. The positive end of the battery is connected to the input of the voltage regulator as well as the VIN input in the Arduino. The servos each have their own ground which are all connected to the ground of the voltage regulator and the ground on the Arduino. The servos also each have their own positive end which are connected to the output of the voltage regulator. This connection is how the servos receive the changed voltage. Through this process I learned a lot more about how to connect circuits and how to add on to existing circuits. My next milestone will hopefully include a modification. I am hoping to make the hand count either by typing one into serial monitor or by saying one into a speaker or to use nRFs and make the connection wireless.

Documentation

Schematics

Final Presentation

Second Milestone

For my second milestone I have finished assembling the hand, and I am able to control it with my glove. While assembling my hand I ran into several different challenges because this hand is slightly different than the hand that I was originally supposed to assemble. This first challenge that I found was that there was only space for four servos instead of five. After coming up with several different solutions, I went to my instructors to see if any of my solutions would work. With the help of my instructors, it was decided that the best way to solve this challenge was to connect the pinky and the ring finger to a single servo. Another problem that I found was that the cover for the forearm section did not fit into the arm. I had to file the part down so that it would be able to fit into the arm. The servos also had to be filed because they did hit each other when they turned. The thumb channel was another challenge that I found because the string would not go through from the joint to the bottom of the hand. I had to drill a hole in the back of the hand in order to make the string go though. Throughout assembling the hand I learned a lot about different ways to solve problems and that there is never one solution, but that one might just work better than another.

First Milestone

For my first milestone I have attached the servos and the flex sensors to the Arduino, so that if I bend a flex sensor it moves one of the servos. This part of my project is important because it is what will be responsible for moving the fingers of the 3d printed hand. When the flex sensors are bent it changes the resistance which then changes the voltage. This is the analog voltage that Arduino reads as an input. The microcontroller of the board has a circuit inside called an analog to digital converter, or ADC, that reads the analog voltage and converts into digital value, a number that the servos can understand. My first step was creating the flex sensors circuit with the Arduino. I then changed the output numbers of the ADC so that it would be easier to make my improvements in the future. I changed the range from 0-760 to 0-180. Next, I followed the schematics from my instructions in order to create the circuit for the servos and attach them to the Arduino. At first I used breadboards to make sure that everything was correct, but then I used this circuit board and soldered the flex sensors to it. In order to complete this milestone I had to solder, read a schematic, put together circuits, and code with Arduino. Before this project I had only used Processing which uses Java, so I had to learn Arduino’s language. While completing this milestone I also learned more about circuits and how all the components work together such as the flex sensors and the ADC. My next steps for this project are to connect everything to the glove and assemble the hand.

Starter Project

My starter project is the Mini POV 4. POV stands for “persistence of vision,” which refers to the ability of the human eye to see objects in one spot even when the object is moving.  When the Mini POV 4 is waved back and forth, the LEDs show a pattern of my design. The Mini POV 4 is powered by a 4.5V source. The two different capacitors work together to stabilize the current and filter out noise. The potentiometer, also known as a variable resistor, controls the amount of current that flows to the micro controller. The potentiometer changes the input to the micro controller, which results in the output changing as well. This is how the mini pov 4 controls the LED blinking speed. The 2.2k resistors limit current flowing to the 3 transistors. Because the micro controller’s signal is not strong enough to communicate with the LEDs, the transistors amplifies the signal so it can. Each LED has it’s own 47 ohm resistor that prevent the LED from overheating. In between the resistors is a ceramic resonator which acts as the board’s metronome and makes sure that the LEDs blink at a consistent rate. The board also has two diodes to make sure electrostatic discharge does not occur. Last, is the USB type B port that allows the user to customize the image on a computer. One challenge I faced while building my starter project was that I attached one of the LEDs incorrectly in the circuit. I had to desolder the LED in order to remove it from the circuit and the put it in the correct way. Through my starter project I learned how to solder and how to connect different parts to a circuit. I also learned about the software program processing because I had use this program to add new designs that I wanted the Mini POV 4 to show.

Leave a Comment

Start typing and press Enter to search