LED lighting – meshed Bluetooth transforms lighting controls networks
From lighting control to the Internet of Things
The transition from existing lighting solutions towards LED lighting is occurring in three distinct phases, each with its own unique characteristics.
The first phase is characterised by replacing traditional light sources such as incandescent light bulbs or fluorescent light tubes with LED-based solutions. The key goal was to reduce the operational cost by means of lower power consumption and longer life time of LED light sources compared to their traditional counterparts.
LED-based lighting uses approximately 75 percent less energy and lasts 25 times longer than traditional incandescent lighting. The US Department of Energy estimated that the full transition to LED lighting could save about 348 TWh of electricity in the United States alone. This is the equivalent of the annual electrical output of 44 electric power plants (1000 MW each) and represents cost savings of more than 30 billion US Dollars at today’s electricity prices. 
The second phase of this transition focuses on the combination of LED lighting with sensors and controls to further optimise energy efficiency and user convenience. Three main control mechanisms are used for that:
- Occupancy sensors allows turning off the light automatically if it is not needed. This is especially beneficial for larger office spaces where individual areas might not be used all the time;
- Ambient light level sensors can adjust the brightness of the indoor lighting based on the amount of available ambient light (so-called daylighting). This is especially beneficial for buildings with large glass fronts where lots of ambient light is available;
- Defining maximum brightness settings for dimmable lights (so-called task tuning) avoids overly lit areas and optimises the light level for individual areas.
To meet these use cases, LED control based on standardised wireless technology is the most effective choice due to quick installation and easy upgrade with minimal interruption. Wireless has increased in popularity in the last decade due to advances in radio technology and the emergence of standards, which enables seamless communication between different devices.
The third phase is characterised by lighting systems becoming a data backbone for IoT applications. There, the lighting system continues to provide traditional lighting; in parallel however it generates and transports a wide variety of sensor data to the cloud.
Taking the example of a lighting system with occupancy sensors, the basic functionality continues to be controlling the light. In addition however, the occupancy sensor data can be used to determine the space utilisation of the office. Furthermore, the wireless network established between the light sources can be used to transport sensor data which is not directly related to lighting control, e.g., temperature, humidity or air quality sensors.
Analysing this data can yield a range of insights, which can be used to make your smart lighting respond to factors such as ambient light, humidity or CO2 levels. You can also use the data to count people, log events, deliver marketing messaging at the right time or help manage crowds.
Wireless protocols and mesh networks
Several wireless protocols exist for wireless lighting controls and for communication in a building automation system.
The energy harvesting wireless or so called EnOcean standard is one of the most established ones. It is defined by the EnOcean Alliance, a consortium of international companies from the building automation industry. The wireless communication in the sub 1 GHz radio band which combines high range with low radio interference due to the absence of Wi-Fi or Bluetooth devices in this band.
Bluetooth Low Energy (BLE, or Bluetooth Smart) is a more recent innovation, created for the Internet of Things. Its first big selling point is that you’ll find it in virtually every smartphone and tablet made in recent years – and it’s the only low-power radio technology that can boast this. You can therefore set up and control a BLE smart lighting system directly, using most existing devices. This makes BLE-controlled systems simple and cost-effective to deploy and run.
One of the companies to leverage this technology is Casambi. Casambi’s wireless lighting control software platform empowers users of smart devices to interact effortlessly with modern lighting around them. The award-winning Casambi solution delivers everything from a basic, individual lighting-fixture control to industrial-scale solutions with cloud-based remote control, monitoring and data logging. Casambi’s technology can be easily integrated at low cost into lighting fixtures, drivers and modules.
Bluetooth based lighting not only enables direct control and configuration from your smartphone, but also new lighting features such as proximity sensing (also known as Beacon technology). There, the Bluetooth network detects the location of individual Bluetooth nodes based on the received signal strength in the individual nodes.
Bluetooth based networks are ideally suited for proximity sensing since the radio range of the individual nodes is – unlike for other protocols such as EnOcean radio protocol – very low. It is therefore possible to determine the location of a transmitter very accurately based on a dense receiver infrastructure.
The location information can be used to Implement proximity-sensitive smart lighting: Automatically activate a preset scene when someone enters a room, or create lighting that follows a person as they move through a building, for example.
It can work in other ways, too: Imagine a light over a shop or museum display, with a beacon built-in. As someone walks up to it, the beacon could trigger the museum’s/retailer’s app on the visitor’s smartphone to show information about the exhibit.
For any wireless device, the aspect of power supply becomes an important topic. The traditional approach of using primary or secondary batteries is not desirable in large-scale commercial buildings where maintenance and downtime are key cost driver.
To understand the challenge, one needs to consider that large office buildings have more than 10,000 individual sensor or switch nodes making maintenance (battery exchange) highly undesirable. Energy harvesting sensors and switches have established themselves for many years as ideal solutions to this problem.
EnOcean, developer of energy harvesting wireless technology, has been deploying such devices since 2003. In October 2016, PTM 215B, the first energy harvesting switch module for Bluetooth Low Energy systems, was introduced. More recently, EnOcean launched wireless and self-powered Easyfit wall switches for Bluetooth lighting systems for worldwide usage.
Combined with self-powered Bluetooth lighting systems from Casambi, Easyfit wall switches offer lighting installers the benefits of maintenance-free, easily positionable and ready-to-use solutions, allowing flexible control as well as intuitive usage.
These self-powered switches use the kinetic energy of the button press to generate a wireless signal for controlling and dimming. In addition, self-powered sensors can be added to address use cases where line power is not available at the desired sensor location.
New lighting solutions based on Bluetooth Mesh networks can provide a new infrastructure for IoT applications. They enable integration and visualisation of different sensor data thus providing much deeper insight into building parameters. These solutions can be easily controlled and configured via mobile phones and tablets making them very intuitive to use. In addition, the possibility to use energy harvesting switches and sensors combines maintenance-free operation with free positioning and easy upgrades. With this, lighting is poised to take yet another technology leap forward.
 Source: Office of Energy Efficiency & Renewable Energy, online article “LED Lighting”, https://energy.gov/energysaver/led-lighting