Keer Zhao
Intro to Physical Computing
----------- 1.0 Story background -----------
You are an explorer, waking up in the middle of the desert. You realized that you just lost consciousness after many days of walking in this endless desert. Right now, you feel extremely exhausted and thirsty. All of the sudden, a flower bud catches your eye. The flower bud looks so mysterious and the beauty just seems so unreal in this monochromatic desert environment.
You slowly approach the flower bud, saw a dried paper lying next to the flower bud, it says:"only when she wakes, what you wish may become true...."
----------- 2.0 Concept -----------
We want to actually set up this 'desert' scene and build this 'mysterious flower bud'. We intend to set three different types of sensors and encourage people to figure ways to make the flower blossom.
----------- 3.0 Overview -----------
----------- 4.0 Design plan -----------
Basically, there are three stages until the bud can be fully open.
We will start by making the flower paddle, which is a combination of wire + tissue paper. Then, a fish wire will be attached to tip of the paddle and linked with a servo. Once paddles are made, they will be somehow wired together to be a flower.
The hard part of this project will be:
1. Making the flower and the entire setup
2. Calculate the angle the servo needs to move in order to pull the paddle
----------- 5.0 Our Progress -----------
Kristina and I start with making the flower. The flower is made of two parts: a central bud and three pairs of paddles. We use wires to make a paddle shape, then wrapped with red paper, finally twisting the remaining paper to its stem and use the glue gun to glue them.
The central bud will remain the same position, the other three pairs will be tied to a servo and being pulled outwards.
This is what the flower looks like in the end. We all agreed that the bare wires are not so good-looking, so we use green threads to cover the stem part. The whole flower stands in a pile of foams, which allows the stability for it to stand, as well the flexibility to open.
While searching for treasures on the junk shelf, we accidentally found a yoyo, which is perfect for placing our FSR. We decided to make a circular 'hat' for the yoyo, put the FSR under it. For decoration, we used green wool thread.
We tested other covers, such as a plastic small plate, foam and some other materials, but the analog value read is not very good. Some pamterials may be too soft or too strong, at the end, we chose wool.
When we set a test run, we realized that the initial circular FSR we used cannot provide a good analog reading (the state of 'release' and 'presses' have close readings). So we have to switch to another square FSR, which reads below 300 when not pressed, and around 800 when pressed.
In order to adapt this new FSR, we set an if condition “if (analogvalue > 300), servo.write".
Prior to that, in the setup, I have set a condition when analogeValue < 300, servoes will stand by at the midpoint, which is the 90 degree. This makes sure that each servo starts at the same degree, and turned to the same angle degree.
Unfortunately, the day before the presentation day, our yoyo was missing. We searched everyplace, but we just could find it. Finally, we decided to use a round plastic piece as the holder for the FSR, and cover it with the 'green hat'.
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Breadboard setup test
Initially, I was worried that the power from the Arduino board alone may not be strong enough to make 2-3 servos move at the same time, but luckily it worked.
Basically, on a white 3D-printed 'half sphere' we found from the junk shelf, we set the flower in the middle, surrounded by three servos in three different directions. Fish wires connect each servo to one of the outer petals and will execute two separate pulls to make the flower bloom.
The servo position must be pre-determined and glued to that exact position so that it prevents the servo itself from being pulled if the servo is not standing strong. The fish wire part is tricky. We adjust it many many times because the servo's position is always changing and the wire itself is hard to handle (although they are strong, they are also slippery and hard to tie together).
Hard-working Kristina is gluing the servo
Final Setup
When the memory fades like a hand of sand
Sweetness and bitterness dyes
Into the blueness of shy
Upon the time together we stand
That's when the last bit of green is kissed
And when the stars are blissed
I shall be there
My love
In order to guide our audience, we also created a piece of the poem as a hint to encourage people to touch the green button and watch the day change from day to night.
My blog talks mainly about the flower part. The whole wheel setup is done by Zoe. That's a really cool project, see more details please check out her blog : )
----------- 6.0 Our Codes -----------
Our codes are simple and straightforward.
There are three servos connect to the Arduino as 'digital output'.
In the setup, I also wrote an if statement for all servos to turn to 90 degrees before the game starts.
The second and third if statements will make servos move when the FSR is pressed.
Our first few tests show the pulling of servos is too sudden, not very elegant. We then wrote a for statement to make the servo slowly pull petals bit by bit.
In the end, we also incorporate a Serial. read that puts servo back to the initial position.
----------- 7.0 Challenges -----------
1. Servo Motion
I tried a long time to figure out why the servo turns more when I enter Servo. write(20) than Servo. write(40). Initially, I thought my codes are incorrect, but it turns out to be: this is just how servo works.
Servos have a set of degree angles built-in. It will turn to a certain degree, rather than turning by a certain amount of degree.
2. Detecting the changing state of a LED light
What we planned to do was when the last star lights up, it triggers the bloom of the flower. We tested to detect the voltage as an analog input, but the reading alternates quickly from 0-1023. Therefore, we put a switch in the circuit, when Zoe is done rotating the wheel, she can click the button.
3. Computer shut down when running Arduino
My computer sometimes just suddenly shuts down whenever I try to run/upload the Arduino codes.
----------- 8.0 Conclusion -----------
I learned a lot throughout this project. The outcome is not exactly what I envisioned at the beginning, but I am happy that we made the flower finally bloomed! I really appreciate how much time Zoe and Kristina put in. We together hunted a lot of treasures from the junk place (in fact, all materials other than servos and breadboard used in this project are from the junk shelf). Special thanks to my friend Shuang Cai for proofreading my poem and made it even more romantic!