Hypercinema
Physical Computing
Computational Media
Physical Computing
Week 05-06 : Midterm Project
Midterm Project
The main reason the three of us formed a team is our shared interest in human interaction. When given the Halloween theme, which primarily focuses on "horror" for the midterm project, Jiyou thought of using a heart rate sensor. Me and Jenn then joined, and we began developing the concept.
[ Intro ]
We decided to create a fear that gives people unpredictable elements by incorporating aspects of traditional Asian ghosts into the Western Halloween setting. As foreigners, the American subway is a dark, damp place that always makes us tense and scared. We placed typical elements of Asian horror, such as a virgin ghost, a snake, and talismans, in the subway setting, with a manually operated effect of the virgin ghost's eyes moving. In the center, we placed an unknown object with a straw shoe texture, inside which we positioned a sensor to create an unsettling feeling for people.
Halloween evokes images of children collecting candy and the phrase "trick or treat!" We wanted to share candy and fun with those viewing our Pcom project, considering how to incorporate Pcom elements. Simply measuring heart rate through a sensor and distributing candy seemed boring, so we decided to add a game-like element where doors automatically open and close based on the measured heart rate, encouraging people to control their heart rate. We chose to use three servo motors to classify heart rate levels into High, Mid, and Low, with corresponding rewards for each level.
For the Halloween atmosphere, we designed a small subway-shaped stage with layered forms to provide an immersive experience for the subjects. To create a floating ghost effect, we hung elements from the ceiling and attached a separate device to move only the eyes.
Functionally, the most important considerations were:
- Hiding places for servo motors and breadboards
- Positioning for the subject's hands
- Sensor location
- Candy dispensing area
The most challenging part was connecting the candy dispensing area with the servo motors and concealing the connection. We utilized elements like benches, trash cans, and ticket machines, designing them to rotate and reveal hidden compartments containing candy for the subjects to retrieve. The input was installed in a location where people's hands could easily reach and view the entire stage, ensuring our intentions were fully reflected.
[ Fabricating Process ]
- Before building the set, we started with simple hand sketches and 3D modeling to establish the scale of the set.
- Our goal was to rescale the large space of a subway station into a more manageable set size while finding the most effective layout that could contain all necessary components.
- By using a 1:1 scale model, we aimed to minimize potential sizing errors during the actual set construction.
- Referring to the model, we used foam board to construct the main structure of the set.
- After creating the images needed for each surface, we printed them and attached them to the foam board.
- To capture the essence of a subway station, we used actual images of subway elements.
- By layering features like pillars and ceiling protrusions, we aimed to give the set a sense of depth and space.
- To visually link the output of each sensor to the subway environment, we used a 3D printer to create objects commonly found in subway stations, such as benches, trash bins, and ticket vending machines.
- We needed a sensor house large enough for people to put their hands in.
- We cut string with a straw-like texture and attached it to the outer surface of a wireframe house.
- Inside the house, we added slippery-textured toys to create a sense of discomfort when people reached inside.
- After creating the circuit, we attached it underneath the set.
- The heartbeat sensor was placed on top of the set, and the servo motors were installed below.
- After installation, we tested whether the servo motors worked properly in response to the sensor input.
- We attached the 3D-printed subway elements to the motors.
- Below the motors, we built and installed a candy dispenser in the form of a box.
- When the servo motor rotated 90 degrees, it revealed an opening where people could take candy from the dispenser.
- We attached the heartbeat sensor to the top of the set.
- Since people might have difficulty finding the exact sensor location when placing their hands inside the sensor house, we thought it would be helpful to make a guide.
- Using clay, we molded a guide to help people place their fingers in the correct position.
- Finally, we installed all the fabricated elements onto the subway set.
- To enhance the atmosphere, we added details like ghosts and talismans to the background.
- We also made the ghost’s eyes move manually to add a more creepy effect.
[ Technical Process ]
- Heart rate sensor(MAX30105) testing
- Decoupling 3 Servo motor
- Combine 3 servo motors as an output and a sensor as an input
- Scaling the sensor range and adding State variables and functions for interaction
- State variables: Stabilization period, Per-person quotas
- User testing and adjusting input range of Low, Mid and High.
- Use the average value of the heart rate in the first 2 seconds after sensing the person's heart rate.
- Each person can have only one candy
- Each servo motor: 220µF (decoupling x3)
- Entire power supply line: around 1000~1200(470µF x3)
[ Arduino Code ]
Link -> https://app.arduino.cc/sketches/521a936f-f60c-406b-97cb-316bb80b4f7e
[ Troubleshooting ]
Doing jumping jacks in place to test the servo motor triggered by a high heart rate…