How One Maker Turned a Cheap Smart Home Display Into a Dynamic Office "Mood Ring"

When consumer tech writer Adam Davidson’s children bought color-changing mood rings over the summer, it sparked an unusual idea for his home office. Rather than relying on traditional, button-heavy smart home dashboards, Davidson decided to build his own ambient status display. By repurposing a popular, low-cost microcontroller board and integrating it with his existing Home Assistant setup, he created a dynamic office "mood ring" designed to convey vital daily information at a glance.

The project centers around what the maker community calls a Cheap Yellow Display (CYD). Priced at roughly $15, the CYD is an ESP32-based development board featuring an integrated touchscreen display. By utilizing ESPHome configuration files that compile directly into custom firmware, users can program the hardware to execute a wide variety of tasks.

Davidson’s CYD already served a primary role in his home office as part of a custom music discovery workflow. Operating alongside his audio streaming setup, the display showcases album artwork for a weekly generated discovery playlist. Tapping the screen allows him to save specific tracks to a shortlist, while a secondary playback cycle lets him add entire albums directly to his Apple Music library with another tap. However, looking for a way to maximize the utility of the screen during periods when music was not playing, Davidson sought an alternative to standard data dashboards. Rejecting the typical layout of boring text and numerical grids, he chose a more experimental, visual approach inspired by childhood novelty jewelry.

The Weather Sets the Colors

The foundation of the office mood ring is driven by current and forecasted meteorological conditions. Leveraging the OpenWeatherMap integration within his Home Assistant server, Davidson pulls real-time local weather data into the system. The platform exposes various conditions, including sunny skies, partly cloudy intervals, rain, fog, and overcast environments.

To translate these conditions visually, the CYD displays a shifting color palette arranged in a ring pattern. Strong yellows represent sunny weather, while softer yellow hues indicate partly cloudy skies. Blue patches signify rain, and muted blue-gray tones reflect fog and heavy cloud cover. As atmospheric conditions shift outside, the display updates automatically, allowing Davidson to assess the weather at a glance. A simplified text label—such as SUN, SUN/CLOUD, or RAIN—accompanies the visual graphics in the center of the display.

To give the interface a more organic feel, the weather pattern incorporates subtle motion whenever office music is playing. While the animation does not analyze audio frequencies or match musical beats, it causes the color patterns to shift gently, making the display feel visually alive without serving a functional notification purpose.

My Calendar Events Change the Ring’s Mood

Beyond tracking environmental conditions, the mood ring integrates closely with Davidson’s personal and professional schedule. The display serves as a visual indicator for upcoming calendar entries, utilizing data pulled from a centralized Home Assistant calendar that aggregates both his work schedule and family activities.

An hour before a scheduled event is set to begin, a small patch of red appears on the ring. As the start time approaches, this red arc expands progressively around the circle. During the final five minutes before the event, the arc begins to pulse, signaling the imminent transition.

To ensure the display remains informative, the center of the mood ring features a numerical countdown indicating the remaining minutes until the event starts, while the event’s title is displayed at the bottom of the screen. Designers of the interface capped the red event arc at 85% of the ring’s total circumference. This deliberate constraint ensures that the underlying weather colors remain partially visible even when an important appointment is moments away.

Sitting for Too Long Puts the Ring in a Bad Mood

The final layer of functionality addresses sedentary behavior during long working hours. Davidson installed an mmWave presence sensor in his home office, configuring a specific detection zone focused exclusively on his office chair. This sensor provides high-accuracy tracking, distinguishing reliably between moments when he is seated at his desk and times when he is away.

The display responds dynamically to prolonged periods of sitting. After 30 minutes in the chair, the ring begins to fade. As the duration reaches 60 minutes, the visual pattern takes on a fragmented, frazzled appearance. By the 90-minute mark, the ring shifts to a dark purple hue edged with jagged red lines.

If Davidson leaves his desk for a brief break of five minutes, the display resets to its normal state. When a sedentary warning is active, the central portion of the screen shows the exact time elapsed in the chair, though upcoming calendar events take priority and replace the sedentary counter when necessary. For Davidson, the visual degradation of the ring serves as an unignorable metaphor for the physical toll of prolonged inactivity, providing a persistent nudge to stand up and move around.

Rejecting conventional smart home interfaces in favor of ambient design, the project reflects a broader philosophy that automation should minimize manual interaction. By transforming an inexpensive ESP32 board into a contextual mood ring, Davidson demonstrated that essential daily information can be communicated through organic visuals rather than cluttered dashboards filled with buttons and numbers.