Path: EDN Asia >> Design Centre >> Consumer Electronics >> Making LED lighting intelligent
Consumer Electronics Share print

Making LED lighting intelligent

28 Sep 2012  | David Andeen

Share this page with your friends

Figure 1 shows the placement of an ALS in a luminaire. The sensor must reside beyond the light of the lamp itself to prevent artificial light from affecting the ambient measurement. In this design, the ALS resides on a separate board and receives shade from the beam supporting the lamp. This straightforward design enables the ALS to turn off the lamp when morning light exceeds a pre-programmed value. RGB sensors can add even more "character" to a lighting application. LED systems like the one pictured here that are equipped with RGB LEDs and ambient light sensors can dynamically tune their color output for application-specific requirements, such as mood lighting on a terrace or department store lighting for a display.

Now let's talk about smart communication in LEDs. Ears and a voice are the next most critical features to make an LED light intelligent. By simply networking lights, you can turn them on and off, or dim them, via the network. This operation alone will reduce energy consumption. Communication also provides quick feedback for outages, necessary maintenance, and emergency situations. This information will save overall system maintenance costs. Both wireless and wired communication methods work effectively in various situations, depending on the network size and geography. Wireless works well in small indoor and larger outdoor applications with a continuous line of sight, available frequency bands, and sufficient headroom for transmission power. Powerline communication (PLC) uses the existing powerlines to provide the communication. PLC works extremely well in large municipal-style lighting installations, tunnels, and indoor parking garages where line of sight is not possible because of geography or building walls. In all communication applications, reliability and robustness are critical. If communication fails, the system provides no benefits.

In wireless applications, signals may run over Wi-Fi, ZigBee, or other standard and proprietary protocols often in, but not limited to, the industrial, scientific, and medical (ISM) radio bands. Limiting power consumption provides network flexibility, and is critical if endpoints use batteries. Figure 2 shows a unique application in which a light switch is equipped with an energy-harvesting RF transceiver. The system harvests the energy used to flick the switch, resulting in a usable DC voltage that powers the radio communication over < 1GHz RF to the light fixture. This switch can be placed anywhere in a room, provided that the signal reaches the luminaire. Without the need to wire the light switch, room design becomes more flexible and lighting control more dynamic.

Powerline communication (PLC) control of lighting uses the existing lines that already deliver power, thus making this method a cost-effective choice. PLC eliminates concerns such as sharing communication frequencies, performance in bad weather, and network maintenance, because communication occurs over maintained lines already delivering power. Range, speed, and robustness are the critical design considerations with PLC. Powerlines carry a tremendous amount of noise, which affects system robustness. G3-PLC communication is a new OFDM-based PLC standard that provides communication over power lines. This standard allows for speeds up to 300kbps, mesh networking capability, and robust mode for high-noise situations. OFDM-based, PLC-controlled lighting networks similar to G3-PLC already exist. Figure 3 shows the PLC installation for a tunnel lighting network, by Nyx Hemera Technologies [4]. This system has already saved 25% in energy and 30% in reduction of maintenance. This large-scale installation supports up to 1022 lights on a single system and communicates over distances of up to 3km.

 First Page Previous Page 1 • 2 • 3 Next Page Last Page

Want to more of this to be delivered to you for FREE?

Subscribe to EDN Asia alerts and receive the latest design ideas and product news in your inbox.

Got to make sure you're not a robot. Please enter the code displayed on the right.

Time to activate your subscription - it's easy!

We have sent an activate request to your registerd e-email. Simply click on the link to activate your subscription.

We're doing this to protect your privacy and ensure you successfully receive your e-mail alerts.

Add New Comment
Visitor (To avoid code verification, simply login or register with us. It is fast and free!)
*Verify code:
Tech Impact

Regional Roundup
Control this smart glass with the blink of an eye
K-Glass 2 detects users' eye movements to point the cursor to recognise computer icons or objects in the Internet, and uses winks for commands. The researchers call this interface the "i-Mouse."

GlobalFoundries extends grants to Singapore students
ARM, Tencent Games team up to improve mobile gaming

News | Products | Design Features | Regional Roundup | Tech Impact