Energy efficiency is a hot topic in today's energy crisis
discussion. With recent technology advancements in energy efficient
technologies, new ultra-low power microcontrollers (MCUs) are helping
to reduce overall energy consumption while also creating a cost
effective solution for wireless applications.
Many of us have experienced temperature differences in our
home, when one room's temperature is noticeably warmer or cooler than
the rest of the house. The reason for this disparity is that the
central air conditioning thermostat only monitors temperature at one
location. However, a simple and easy solution for an intelligent
temperature monitoring system exists and can create a more energy
efficient home simply by monitoring temperature wirelessly across
multiple rooms in a house. This method of wireless monitoring
ultimately means no more messy wiring and the ability to quickly
identify which part of the home is not the ideal temperature.
To achieve this type of energy efficient home, small sensors
are mounted around the home and continuously transmit temperature
levels wirelessly to a personal computer, providing timely and accurate
information regarding the current temperature levels. With this type of
data, areas of the home that may require improvements can be easily
identified. Knowing which areas of the home are unable to maintain
desired temperature levels can be an indication that the insulation in
the home is no longer effective. A quick, simple inspection can offer
feedback on whether the home needs an upgrade in insulation. In this
case, installing new insulation in parts of the home is much more cost
effective versus replacing insulation in the entire home.
To further increase energy efficiency, the use of intelligent
home automation technology can manage air-flow by controlling motorized
vents that dynamically open or close based on temperature levels. This
technology can even wirelessly control window blinds based on sunlight
levels, eliminating the need for expensive window tinting.
This type of home automation system can easily be deployed by
using Texas Instruments' eZ430-RF2500 low cost, ultra-low-power
wireless tool (Figure 1). This tool consists of TI's highly integrated
MSP430F2274 microcontroller coupled with TI's CC2500 2.4GHz wireless
transceiver. The MSP430 MCU has many built-in peripherals including an
internal temperature sensor, eliminating additional external
components. The $49 eZ430-RF2500 tool is not only a wireless
temperature sensor, but also offers a complete development package for
users to create their custom wireless solutions. The tool is small and
discreetly mountable in any part of the home, and can drastically
improve home energy efficiency with only a small upfront cost.
on image to enlarge.
The tool's firmware is pre-loaded to wirelessly monitor
temperature with an included temperature monitor graphical user
interface (GUI) to allow customers to quickly start the development
process. The firmware is built upon TI's proprietary SimpliciTI
wireless network protocol, which allows central access point networking
with multiple range extenders and end devices to expand the wireless
temperature monitoring network anywhere in your home (Figure 2).
(SimpliciTI can be downloaded online at no extra cost.) To expand the
wireless network additional wireless modules are required, which can be
purchased for around $20.
on image to enlarge.
With an upfront cost of approximately $169 ($49 + 6x $20) "
covering three rooms, one living room, two bathrooms and one kitchen "
a user can have a fully functional, monitoring system in their home.
These wireless modules are also ultra-low-power devices since each
module requires only 2 AAA batteries that can last up to three years
with every second of transmission. Such low-power operation can be
achieved through the MSP430 MCU's intelligent low-power-modes. These
modules periodically wake up from low-power-mode every one second
through a timer generated interrupt to sample the room's temperature
and transmit a packet to the access point. After the transmission, the
modules go back to low-power-mode as illustrated in Figure 3.
on image to enlarge.
Just a few years ago, having an intelligent home monitoring
system required a lot of effort. But now through the use of wireless
technology and the eZ430-RF2500 tool, expensive intelligent monitoring
systems with messy wiring are a thing of the past. Now, users have the
flexibility to create custom wireless solutions that meet their home