18-08-2012, 01:42 PM
Automatic Room Light Intensity Detection and Control Using a Microprocessor and Light Sensors
Automatic Room Light.pdf (Size: 696.17 KB / Downloads: 155)
Abstract
In this paper we propose a design using both a
microprocessor and light sensors for automatic room light
detection and control. Our design, the HLCM (Home Light
Control Module) which will be installed in every light fixture
of a family, is made up of four blocks: the pyroelectric
infrared (PIR) sensor circuit, the light sensor circuit, the
microprocessor and the RF module. By using the PIR sensor
circuit, the HLCM detects if a human body enters the
detection area or not. If there is no human body present, all
controlled lights are turned off. If there is, the HLCM detects
the light intensity under the environment and maintains
sufficient light by controlling the number of lights. We have
also integrated an RF module to transmit and receive the data
from each HLCM so we can control different lights in
different regions.
INTRODUCTION
In recent years the energy crisis has become one problem
which the whole world must confront. Home power
consumption makes up the largest part of energy consumption
in the world. In particular, the power consumption of lamps in
a typical home is a factor which can’t be ignored. The typical
user needs different light intensities in different places.
Sometimes the light intensity from outside is sufficient, and
thus we don’t need to turn on any light. But sometimes the
user leaves but forgets to turn off the light. These factors
cause energy waste. Therefore some power management of
light control in a home is necessary in order to save energy.
DESIGN OF THE HLCM
The HLCM shown in Fig. 2 is made up of the PIR sensor
circuit, the light sensor circuit, the RF module and the lowpower
MCU. We also provide a DC power supply from AC
power to every component.
We use the PIR sensor circuit to detect whether someone is
passing through the detection area or not. If a human body
enters the detection area, the PIR sensor receives the
variations of the temperature made by the infrared energy
emitted to the surroundings, and if necessary produces the
variations of electric changes by means of a pyroelectric effect.
Because the electric charges are very few and not easily
sensed by the sensor, we adopt the high-impedance FET to
pick up the signal. Since the output amplitude of the sensors
we measure, about the level of mV, is not large enough for an
MCU.
RESULTS OF THE EXPERIMENT
Fig. 6 shows the implementation of the HLCM. The
hardware prototype circuit of the HLCM is now
implemented on an 8 cm × 6 cm printed circuit board
(excluding the SSR).
The power consumed by the HLCM can be measured
and calculated as shown in Table II.
We compare the change of the value of light intensity
under the same environment between that measured by
our design and that of the traditional design measured by
a digital light meter. We place a digital light meter 200
cm below a light. Because the HLCM is adjacent to the
light, and the light intensity measured by an HLCM is
higher than that measured by a digital meter, we have to
adjust the value measured by the HLCM to make it
similar to that measured by the digital light meter, as
shown in Fig. 7.
CONCLUSION
In this paper we have proposed a design for automatic room
light detection and control. We install an HLCM at every light
of a family for home power management. The HLCM detects
if a human body is present or not by using the PIR sensor
circuit. If there is no human body present, all lights are turned
off. If there is, the HLCM then detects the light intensity
under the environment by using the light sensor circuit and the
system maintains sufficient room light by switching lights
on/off. To realize light intensity support and light pre-control,
the RF technology for light power management has been
integrated. Consequently, the potential of the features of low
cost, small size, low power consumption and power saving
has been shown.
Automatic Room Light.pdf (Size: 696.17 KB / Downloads: 155)
Abstract
In this paper we propose a design using both a
microprocessor and light sensors for automatic room light
detection and control. Our design, the HLCM (Home Light
Control Module) which will be installed in every light fixture
of a family, is made up of four blocks: the pyroelectric
infrared (PIR) sensor circuit, the light sensor circuit, the
microprocessor and the RF module. By using the PIR sensor
circuit, the HLCM detects if a human body enters the
detection area or not. If there is no human body present, all
controlled lights are turned off. If there is, the HLCM detects
the light intensity under the environment and maintains
sufficient light by controlling the number of lights. We have
also integrated an RF module to transmit and receive the data
from each HLCM so we can control different lights in
different regions.
INTRODUCTION
In recent years the energy crisis has become one problem
which the whole world must confront. Home power
consumption makes up the largest part of energy consumption
in the world. In particular, the power consumption of lamps in
a typical home is a factor which can’t be ignored. The typical
user needs different light intensities in different places.
Sometimes the light intensity from outside is sufficient, and
thus we don’t need to turn on any light. But sometimes the
user leaves but forgets to turn off the light. These factors
cause energy waste. Therefore some power management of
light control in a home is necessary in order to save energy.
DESIGN OF THE HLCM
The HLCM shown in Fig. 2 is made up of the PIR sensor
circuit, the light sensor circuit, the RF module and the lowpower
MCU. We also provide a DC power supply from AC
power to every component.
We use the PIR sensor circuit to detect whether someone is
passing through the detection area or not. If a human body
enters the detection area, the PIR sensor receives the
variations of the temperature made by the infrared energy
emitted to the surroundings, and if necessary produces the
variations of electric changes by means of a pyroelectric effect.
Because the electric charges are very few and not easily
sensed by the sensor, we adopt the high-impedance FET to
pick up the signal. Since the output amplitude of the sensors
we measure, about the level of mV, is not large enough for an
MCU.
RESULTS OF THE EXPERIMENT
Fig. 6 shows the implementation of the HLCM. The
hardware prototype circuit of the HLCM is now
implemented on an 8 cm × 6 cm printed circuit board
(excluding the SSR).
The power consumed by the HLCM can be measured
and calculated as shown in Table II.
We compare the change of the value of light intensity
under the same environment between that measured by
our design and that of the traditional design measured by
a digital light meter. We place a digital light meter 200
cm below a light. Because the HLCM is adjacent to the
light, and the light intensity measured by an HLCM is
higher than that measured by a digital meter, we have to
adjust the value measured by the HLCM to make it
similar to that measured by the digital light meter, as
shown in Fig. 7.
CONCLUSION
In this paper we have proposed a design for automatic room
light detection and control. We install an HLCM at every light
of a family for home power management. The HLCM detects
if a human body is present or not by using the PIR sensor
circuit. If there is no human body present, all lights are turned
off. If there is, the HLCM then detects the light intensity
under the environment by using the light sensor circuit and the
system maintains sufficient room light by switching lights
on/off. To realize light intensity support and light pre-control,
the RF technology for light power management has been
integrated. Consequently, the potential of the features of low
cost, small size, low power consumption and power saving
has been shown.