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Fox Grapes:
Overview
Overview
For our final project in Intro to Physical Computing, our team, Fox Grapes, worked with a client on campus named Heidi to design a device that fits into her everyday life. Heidi does a lot of focused work in her office, and people stopping by in the middle of it was breaking her concentration. Our answer to her problem was the
Flow Status Indicator: a light she controls from her desk that tells anyone outside her door whether it is a good moment to come in.
I was responsible for the indoor control unit and the LED looping code, Hayool built the CAD model and housing for the 3D print, and Wendy did the electronics for the outdoor LED and programming the transceiver.
What we built
What we built
The Flow Status Indicator has two parts that talk to each other by radio, so there are no wires running between Heidi's desk and her door. On her desk sits a small glowing button. When she presses it once, it lights up green, and the light outside her door turns green with it. Each single press after that moves both lights to the next status:
Green: come on in.
Yellow: I'm busy, but knock if it matters.
Red: please do not disturb right now.
A quick double press turns both lights off. I wanted the whole interaction to take one hand and less than a second, so Heidi never has to look away from her work to use it.
Both units side by side, showing green.
The First Status
One press from green moves both lights to yellow: busy, but knock if it matters.
One more press moves both lights to red: please do not disturb.
IMG_2808.movThe lights in action
The lights in action
A day with the Flow Status Indicator
A day with the Flow Status Indicator
Heidi gets to her office in the morning and has a report to finish before lunch. She presses the button on her desk once, and the light by her door turns green, so a coworker with a quick question knows they can come right in. When she settles into the hardest part of the report, she presses twice more and both lights move through yellow to red. A colleague walking over sees the red light by the door, decides it can wait, and comes back later. When Heidi is done, one more press takes the lights back to green, and at the end of the day a double press turns everything off. In our first meeting, Heidi walked us through her workday and told us how often people drop by while she is trying to focus. What stood out to me was that she did not want to shut people out; she just wanted a gentle way to say "not right now" without having to stop and say it.
Getting to know Heidi
Three prototypes, three questions
Three prototypes, three questions
We built three quick prototypes, each one answering a single question:
One light with a built-in button: is pressing the light itself a fast and natural way for Heidi to change her status?
Three LED boxes, each with its own button: does a dedicated button for each mode make the status clearer?
A screen display: do visitors need words or a key to understand what the colours mean?
What we learned from Heidi's feedback
What we learned from Heidi's feedback
She preferred something she could use with one hand, and wanted it to be fun to use.
One button worked better than several.
She liked the idea of a clamp on the side, and adhesive or a screw holder would work for mounting.
She chose the retro cube form.
The light should be bright, but diffused well.
She does not mind getting up to reach it, and there are outlets on both sides of her desk.
Building the product
The photos in this section follow the build of the final device, from the first electronics tests through CAD, printing, and assembly. Further down, I go back to where it all started: the interview with Heidi and our first prototypes.
Soldering the electronics in the lab.
CAD of the button enclosure, broken into its parts: the top, the diffuser layers, the base plate, and the frame that holds the electronics.
A render of the enclosure in a clear material, which I used to check how the LEDs would sit inside before printing.
A render of the stacked enclosure layers, showing how the tiers sit on top of each other.
A button and display stacked, to emphasize the sliced retro prism design
The same in green, with my hand next to it.
Schedule
Schedule
Our plan gave Wendy the electronics and programming from October 30 to November 6, while I worked on the indoor control unit and Hayool worked on the CAD. All three of us set aside November 7 and 8 for assembly and testing, ahead of the final critique on November 9.
Final critique and what we learned
Final critique and what we learned
Based on the feedback received during the final critique, the overall response to the Status Light for Heidi was overwhelmingly positive, with reviewers praising its sleek, elegant, and minimal design, intuitive one-touch usability, and impressive long-range wireless sync. Key praise highlighted how clean, simple, and satisfying the physical interaction is, with one reviewer noting it as "such a clean, simple, and thorough solution to a problem" and another remarking that it was a "device that I want... designed for manufacturing."
However, the feedback consistently pointed to two main areas for improvement: accessibility and power/hardware refinements. Multiple reviewers emphasized that relying only on color (green, yellow, red) creates barriers for colorblind users or individuals with visual impairments, suggesting sensory alternatives such as distinct shapes, pulsing lights, or pixel icons or even written labels .
On the technical side, critics recommended exploring long-term power solutions such as battery power or solar charging, fine-tuning light diffusion to reduce visible internal LED spots, and fixing slight internal light alignments to preserve the clean, minimal aesthetic. Moving forward, the key takeaway for out team is to integrate inclusive accessibility principles and refine the hardware enclosure while maintaining the satisfying physical interaction that made the design so successful.
Technical details
Technical details
Each unit runs on an Arduino Pro Micro with an nRF24L01+ radio module. The radios run on 3.3 V, with a 10 µF capacitor across each module's power pins to keep them stable. The desk unit reads its button on pin 2 and drives its LEDs from pin 6 through a 330 ohm resistor. The door unit drives its LEDs from pin 6 through a 330 ohm resistor, with a 1000 µF capacitor across its 5 V supply.
[Placeholder: block diagram, exported as PNG.]
[Placeholder: electrical schematic, exported as PNG.]
Code
Code
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