wearable light timer
duration ⇾ 3 weeks
​tools ⇾ adafruit feather, neopixel ring, flex sensor, gym glove, bread board.​
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the wearable represents time as a gradual accumulation of light on a circular NeoPixel ring.
the timer is controlled entirely through hand posture using a flex sensor.​
flex sensor
paused state
restarting
time running
code
this prototype uses a flex sensor to switch between three interaction states: run, pause, and reset.
it maps elapsed time to a 16-pixel NeoPixel ring.
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key parameters:
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FLEX_ON (6000)
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starts the timer when the wrist is flexed upward (high plank)
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FLEX_OFF (9000)
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pauses the timer when the wrist returns to neutral
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RESET_ON (15000) + 3-second hold
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resets the timer when the wrist is flexed downward and held
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using two thresholds for running (FLEX_ON and FLEX_OFF) prevents rapid switching caused by small sensor changes, keeping the timer stable.
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how does time become light?
elapsed time increases while the plank posture is detected, the lit pixels is proportional to time:
lit_pixels = int((elapsed / DURATION) * RING_PIXELS)
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running
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newly lit pixels are assigned random colors and stay consistent
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paused
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lit pixels turn red to indicate stop
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complete
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the ring blinks green twice, then resets
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prototyping
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breadboard prototype of the wearable system used to test flex sensor readings and validate LED timer behavior before final integration.
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mapping discrete LED pixels to continuous time
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adjusting brightness to maintain clarity without glare
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sensor placement and threshold tuning were critical to ensuring reliable posture detection during physical movement.
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calibrating flex sensor values for high plank, neutral, and reverse flex positions.
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to stop the timer from rapidly switching between running and paused due to small hand movements, I used two different threshold values which creates a buffer that keeps the state stable.
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testing hold-based reset detection.
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full demonstration of the final integrated wearable
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the flex sensor embedded at the wrist of the glove, showing posture-controlled activation
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LED time progression during high plank, pause in neutral position, and reset through reverse flex hold.
interaction demonstration & insights
in the demonstration:
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the timer begins when the hand enters high plank position.
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LEDs progressively fill as posture is sustained.
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returning to neutral pauses the timer (red state).
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holding reverse flex for three seconds resets the system.
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completion triggers a double green blink.
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this project demonstrates how wearable interaction can shift time perception from numeric tracking to embodied experience.
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by removing screens and numbers, the device reduces cognitive load and emphasizes physical engagement as the mechanism of control.
