Brian Krenz

User Experience Designer


Moodlighting Personal Informatics System

About This Project

Time of Project
  • Jan 2012–Apr 2012
Skills Applied
  • Sketches
  • Wireframes
  • Mockups
Technology Used
  • Whiteboard/sketches
  • Adobe Illustrator
  • Peter Andrews
  • Killian Escobedo
  • Jeannette Schroeder

For a personal informatics course, my team and I designed and built an Arduino-based prototype for tracking light exposure. We plotted this data against various mood measures – primarily, level of sleepiness – and created a visualization showing the correlation between these two measures.

The impetus for this project was research on Seasonal Affective Disorder, which indicates that low-light exposure can lead to depression in some people. Our goal was to provide people who may be suffering from depressive symptoms a system for assessing how their daily light intake might factor into their overall mood.

The Prototype

My teammate took the lead on building the prototype and assembling the Arduino code. The images below show the completed device. The device contains two sensors – a luminosity sensor and an RGB-color sensor. We paired the light data with an hourly, one-question survey asking the user to report level of sleepiness.

The prototype, closed, with the light sensors exposed
The prototype, closed, with the light sensors exposed
The prototype, opened, revealing the circuitry
The prototype, opened, revealing the circuitry


Early sketch I made of the visualization

To the right is an early sketch I made, showing what this visualization and UI might look like.

Below is an image of the final visualization. The top line shows sleepiness; greater amplitude indicates feeling more awake. The bottom line shows luminosity; greater amplitude here indicates greater brightness. The darker the shade of blue, the more blue light the user received. Some studies have found that exposure to more blue light is positively correlated with mood. Finally, the top of the visualization depicts cloud cover.

The data below is real data that was collected over the course of a day. We were happy to see a correlation between level of tiredness and light exposure. Click the image to be directed to an interactive version.

Real-World Concept

As a final stage in this project, I envisioned what this device might look like if actually brought to market. I explored many options, including a watch, a necklace, an earpiece, and more. All of these were deemed problematic as clothing or hair could easily cover the sensors, rendering the device useless.

The solution that my team and I settled on was a pair of glasses, which I mocked up to further flesh out the concept.

Concept for real-world design of light tracking system

Poster Presentation

My team and I also presented at a School of Information-run event. The poster of our presentation can be viewed here (PDF).

Portion of poster presentation at School of Information
Poster presentation and demo at School of Information