Our ART device, Coherence, generates user-controlled laser patterns on a screen as users interact with it. The device is presented as a portal-like “universe simulation experience” and provides a chance to “practice aligning the two dimensions of cosmic destiny” by changing the speeds of the two motors that control the pattern drawn by the laser.
The device itself is an octagonal box with a dark, round screen on top. In operation, the laser is projected onto the back of the screen from inside the device, and a glowing ring of light surrounding the screen pulses with different colors/frequencies to indicate the passage of time. The laser bounces off two mirrors before being projected, and each mirror is attached to a motor shaft at a slight angle to oscillate the laser beam’s path. When the motor speeds are integer multiples of one another, the pattern drawn seems to stand still on the screen, creating a multi-lobed flower shape. The user has four controls throughout the experience:
1. Clapping twice, to begin. At the base of the screen is a glowing set of clapping hands, which blink to show the user to clap. This is our non-contact input.
2. A large lever on the left side of the device, which the user moves forward and backward as a throttle for the first motor. Its position is read by a potentiometer, making it our analog input.
3. A large, heavy wheel on the right side of the device, which controls the second motor’s speed. The wheel is mounted on ball bearings and has a printed encoder pattern on the inside face, which is read by an IR sensor. The signal is then filtered with a Schmitt trigger and its frequency controls the second motor’s speed. This is our primary large-scale motion input.
4. A button at the base of the screen allows users to save/hold the wheel’s speed reading, and release it later. This gives users a chance to focus on fine-tuning the motor speed ratios using the lever, instead of having to keep the wheel turning. When the wheel’s speed reading is being held constant, the button glows a steady green.
Welcome Mode:
When the user first approaches Coherence, a blinking, internally-lit headphone stand beckons them to pick up a set of headphones and put them on. A computer-generated recording of a woman with a British accent plays on repeat, from an Adafruit sound board, with calm background music, welcoming the user to Coherence and asking them to clap twice to begin. Throughout the welcome mode, the laser is turned on with one motor running, creating an egg-shaped green outline on the screen to pique users’ curiosity and beckon them. The glowing time-passage indicator ring slowly pulses red.
The user then claps their hands twice (the non-contact interaction). A proximity sensor facing the user ensures that the ART device only responds when a user is standing in front of it, which prevents other ambient noises from spuriously triggering it. A sound sensor board and signal conditioning circuitry then convert the two claps into a digital signal that causes the ART introduction to begin.
Introduction Mode:
When the device detects two claps, the laser turns off and another computer-generated recording plays for 15 seconds, explaining how users can practice aligning the dimensions of cosmic destiny by using the various controls. The message finishes with, “You will have 45 seconds. Good luck.”
Running Mode:
When the 45 second experience begins, the laser turns back on and the time-passage indicator ring starts slowly pulsing blue. Music is played to the user through the headphones. When the user “unlocks” one of the steady flower patterns, the music changes (this is our user feedback).
The frequency and color of the time-passage indicator ring change as the 45 second period ends. First, at 30 seconds, the lights change from blue to purple and the frequency increases slightly. Then, at 40 seconds, the lights change from purple to red and pulse even more quickly. At 45 seconds, the lights and laser turn off and the device enters Reset Mode.
Reset Mode:
In reset mode, the computer-generated voice thanks the user for participating, bids them enjoy the rest of their time on this earth, and asks them to hang up the headphones when they leave. The device then waits through a reset period, which allows the laser to cool down, and enters welcome mode again.
Team 18: Coherence 