A group of students at Carnegie Mellon University have developed a combined hardware-software system designed to take full advantage of natural light sources to regulate artificial illumination in buildings.

GreenLight system makes the most of available natural light

Most buildings are equipped with artificial lighting systems which light entire rooms by electricity. This kind of energy use is clearly inefficient when there are also sources of natural light available. Now four students from Carnegie Mellon University in Pennsylvania, USA, have developed anenvironmentally-friendly lighting system which takes full advantage of natural light, thus saving both energy and dollars. The GreenLight system monitors the light level in a room and then adjusts the brightness of the artificial light sources so as to automatically maintain a comfortable ambient light level by taking full advantage of available natural light and reduce the amount of energy required to illuminate a room.

Regulating artificial light according to natural light levels

The system comprises two separate hardware components equipped with sensors, plus an Android web app. The sensor placed in the room reads ambient light levels using a photocell and sends this data over WiFi to the GreenLight server, which calculates the appropriate amount of artificial light needed in the space, based on the ambient light readings from the sensor, also taking into account the user’s stated light preference settings, and then sends this information to the dimmer switch, which adjusts the artificial illumination accordingly. The GreenLight system allows you to edit the default light level in your room, adjust the system remotely and also create customized lighting schedules. In addition, the mobile app makes use of a Bluetooth Low Energy connection to notify users whenever they enter a GreenLight-equipped room so that they can immediately adjust the settings via their mobile devices. One of the main advantages of the system is that it is wireless and can work off any existing WiFi network. In addition, it costs less to install and can easily be retrofitted into older buildings.

Smart energy management

GreenLight also provides software that enables administrators to monitor and compare electricity consumption and cost metrics over time. The system also computes energy savings into dollar savings. These metrics can be viewed at the individual room level, or aggregated to the level of the entire building. The developers estimate that the GreenLight system should pay for itself (purchase price plus installation cost) in one year. The project caused quite a stir among a large audience when it was unveiled at the inauguration celebration to welcome Dr Subra Suresh as ninth president of Carnegie Mellon University and again at the university’s annual Information Systems Senior Project Fair. In fact other influential players in the ICT sector are becoming increasingly interested in home automation systems and connected objects that enable smarter energy consumption management – Google’s recent acquisition of California-based Nest Labs being a prime example. Meanwhile, GreenLight, which enjoys strong support from Carnegie Mellon, is expected to launch in the near future.

By Manon Garnier