IoT-ready smart lighting manager ICs feature
multi-sensor support
Lee Goldberg - May 20, 2015
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Ams's new Smart lighting manager ICs bring a precious bit of sanity to a market where the very
term "Smart Lighting" is so over-used and under-defined that it's in danger of becoming
meaningless. Like many other MCU-based connected lighting controllers, the AS7211 and AS7221
devices support network-commanded dimming, daylighting and other basic smart lighting functions.
They can also run in an an autonomous mode which only relies on a local or remote host for
configuration and exception handling. Unlike most of their counterparts, both controllers are
equipped with highly-accurate integrated light sensors which enable precise daylighting, lumen
maintenance, and, in the case of the AS7221, color tuning. In addition, the same sub-$10 solution
that drives the lighting system can also serve as a low-cost platform for many other Smart Building
services.
network-commanded dimming, daylighting and other basic smart lighting functions. Unlike most of
their counterparts, the controllers can also function in an autonomous mode which only relies on a
local or remote host for configuration and exception handling. Equally important the same sub-$10
solution that drives the lighting system can also serve as a low-cost platform for many other Smart
Building services.
Fig.1: The ams AS7211 Smart Lighting manager controls single-color LED lights and constantcurrent fluorescent lights.
The AS7211 is intended for use in florescent and single-color LED lamps and luminaires. It is
equipped with embedded digital ambient light sensors (ALS) to provide single-device, closed-loop
and automatic adjustment of the brightness of the light source they're driving, enabling them to
maintain constant Lux in response to available daylight. AMS claims that, when used with an
infrared filter, the ALS's photopic response allows an accurate approximation of the human eye
response to visible light. This enables highly accurate Lux readings, even in the presence of high-IR
sources such as sunlight or nearby incandescent fixtures.
Fig.2: The ams AS7221 is intended for variable CCT and spectrally tunable lighting
applications.
The AS7221's tri-color mixing/sensing abilities are best suited for human-centric lighting
applications where high quality light is achieved by combining the output of two or three different
LEDs. The lighting manager incorporates an embedded digital tri-stimulus true color nano-optic
sensor providing direct CIE1931 XYZ and CIE 1976 u’v’ coordinate mapping for closed-loop,
autonomous adjustment of variable CCT and spectrally-tunable LED lamps and luminaires.
Despite their differences, both devices share a large common core of networking, control, and socalled "cognitive lighting" capabilities which enable lights to be “aware” adapting to their
surroundings to autonomously manage lighting to meet esthetic, quality and energy efficiency needs.
While Cognitive Lighting may sound like just another fancy buzzword it is a useful shorthand term
for how the ams architecture pushes sensing, intelligence and decision-making abilities as close to
the network edge as possible. In other words, these controllers don't just generate data and push it
to the central controller, they are capable of using it locally to make decisions about managing
lighting parameters without remote intervention.
These same abilities also make it possible for the lighting manager to act as a sensor hub, providing
ultra-low-cost IoT connectivity for distributed sensors, such as occupancy, temperature or
smoke/CO. Since their smart lighting platform provides open, flexible and "virtually free"
connectivity for multiple sensor networks, it's easy to see why Tom Griffiths, Sr. Marketing Manager
at ams says that "lighting with integrated controls will become the sensor hub of the IoT."
Fig.3: The ams Smart Lighting architecture enables deployment of "virtually free" IoT-based
sensor networks.
The AS72XX platform uses standards-based interfaces wherever possible to insure interoperability
and easy integration with existing products and systems. For example, "dumb" luminaire control for
the AS7221 is accomplished through 0- 10V compatible dimming input, plus 3 direct PWM channels,
one of which can be optionally enabled for 0-10V analog dimming output. Both devices are also
compatible with standard dimmer controls and occupancy sensors.
The manager's smart lighting control functions are equally simple and can be accessed through a
simple UART serial interface, making it easy to connect to network hardware clients for protocols
such as Bluetooth, WiFi and ZigBee. The managers accept a straightforward Smart Lighting
Command Set (SLC) which uses text-based AT-style commands to control and configure a wide
variety of functions such as on/off(ATON/ATOFF) dimming (ATDIM=50), and Lumen maintenance
(ATLUXTARG=400). The software development kit includes a rich library of so-called "configuration
elements", pre-written SLC command scripts which define preset scenes or transitions between
different types of spectral presets, including the time and transition speed as well as initial and final
illuminance levels.
Fig.4: A simple application interface makes the AS7211/AS7211easy to program and configure.
Pricing for the AS721x Autonomous Daylighting Manager family is less than $3 in quantities of 5,000
pieces. Selected high-volume customers are testing sampled devices now, with production devices
available in Q3 2015. Ams expects that a complete, ready-to-integrate lighting management solution
will cost "comfortably less than $10 in low-to-medium volumes and is expected to add $5 or less to
the BOM cost of very high volume applications. This is an excellent deal for a lighting manufacturer
if you agree with recent market studies which indicate that the features these devices make possible
add roughly $75 to the value of a typical fixture.
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