Home automation: Engineering a home with eyes, ears and plenty of smarts

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This article looks at how leading-edge innovation and electronic component technologies are supporting advanced smart home security and monitoring solutions.

By Paul Golata, senior technical content specialist, marketing,, Mouser Electronics

My third daughter recently graduated from college with an art degree. I have had the opportunity to see her artwork displayed in areas made to resemble a museum. Besides the artwork on the wall, museums always make me think of security. If you are a fan of heist movies, you know that the plot always requires that the thieves employ ingenious efforts to get in and snatch the priceless treasure. They must manoeuvre through all sorts of security arrangements—laser beams, motion detectors, pressure sensors, and the like. How awesome it would be if our homes had the same technical advantages?

Home automation has evolved into the ‘connected home’—a broad system of home electronics that has so much intelligence it can quickly repay owners for the upfront investment costs through savings stemming from efficiency, all within a relatively short period of time. The connected home promises to bring further automation into the home, linking together disparate technologies, appliances and devices, to coordinate them into a synergistic platform that serves home owners, all within the control of their fingertips. As a simple and fully integrated system, home automation offers home occupants’ peace of mind, which in today’s chaotic and turbulent world is of enormous economic value.

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One aspect of home automation that ensures peace of mind involves home security and monitoring systems. This article looks at how leading-edge innovation and electronic component technologies are supporting advanced smart home security and monitoring solutions. These advances stem from new developments in electronics, technology, and design areas involving power, sensing, compute and control, as well as communications. Home automation is remaking the home environment—making it safer and more convenient (Figure 1).

Figure 1 This image illustrates the details of an intelligent home security system

Security and monitoring
Consider that you have a home automation system that could provide security and monitoring along with a wide variety of entertainment options. This home would incorporate infrastructure that can transmit and receive secure high-speed internal and external communication. It would do so in a manner that both optimises and minimises consumption of resources such as power, water, gas, and data. This automated home would have the intelligence to allow it to act as its own steward for low-end tasks within the home, operating in a manner analogous to a well-intentioned house sitter. This type of automated house would be both smart and connected.

Today’s electronic components have become more affordable while simultaneously increasing performance capabilities. Also, communication infrastructure and services have become wonderfully standardised, convenient and ubiquitous. The integration of both passive and active semiconductors to produce these complex infrastructures has brought forth a network so powerful that it equates to a personal, 24/7, around-the-clock, electronic butler in your home or on your property.

Automated homes—multiple separate systems that one integrates to work together
In its simplest form, one might envision an entire network as being connected in the manner shown in Figure 2.

Figure 2: Connected homes host a network of devices (Source: AVX)

Since our focus is on security and monitoring, we will avoid further discussion on the three other blue blocks in Figure 2. The three areas that we will not discuss in this article include:

  • Smart heating, ventilation, and air conditioning (HVAC) and smart lighting control
  • Smart meters for utility monitoring
  • Communications and entertainment

Before the development of the smart home, false alarms of intruder detection could account for up to 98 per cent of security triggers. This high level of false-positives is expensive and ends up producing a syndrome similar to the Aesop’s Fables classic, ‘The Boy Who Cried Wolf’.

Smart sensors now have wireless capabilities, allowing for their optimal placement around the home. Many smart sensors have the requisite intelligence to ascertain what a true positive-alarm trigger condition is, thus avoiding false-positives. Programming options through improved command and control products, like microprocessors, allow for custom tailoring of sensors, especially for specifications such as sensitivity and multiple-confirmation triggers that assist with improving accuracy when identifying a legitimate alarm trigger.

Occupant health monitoring is a growing area of development due to the creation of powerful accelerometer monitors and motion/temperature sensors. The sensors available now include those for monitoring water (H2O) leaks, carbon dioxide (CO2) and carbon monoxide (CO) build-up, and other volatile organic compounds (VOCs). Likewise, there are other important solutions that monitor the health and efficiency of HVAC systems, relative to their specifications.

Power
Turning our attention to the four key technology-related design considerations of power, sensing, command and control, as well as communications, which enable home automation security and monitoring, let’s start by examining how power management technology advances are accelerating the process.

Power management is a key design challenge in every Internet of Things (IoT) and home automation security product. The capability to cater to high-peak current demands and very lengthy, low-power system standby times requires solutions that extend battery life.

Electronic component manufacturers focus on offering a wide variety of products in which electrical energy gets efficiently used and distributed where it is essential.

Non-isolated direct current to direct current (DC-DC) and point-of-load (POL) power supplies function in security and monitoring applications. On the input side, power may come in via wired-power options, often through 12V DC, or by using a battery-powered option (with the possible inclusion of super capacitors—a type of high-capacity capacitor) or often, in the form of electric double-layer capacitors (EDLCs).

DC-DC power converters that adjust the input voltage to what the system needs to output are often in operation. Designers working on such power converters may consider high-quality, synchronous buck converters, as they are compact and easy-to-use. These parts may provide ample efficiency advantages over low-dropout (LDO) regulators.

When home automation systems use battery-powered devices, designers often employ step-down converters. These assist with battery based applications, as they are capable of drawing very low quiescent currents (IQs), guaranteeing that the part will draw low currents from the battery when in a wait state.

Capacitors are key components for efficient power conversion. One common thread among high-efficiency switch-mode power supplies, microprocessors and digital circuit applications is the need to reduce noise while operating at higher frequencies. Specifically valuable for filtering, tantalum capacitor technology has many of the ideal characteristics that DC-DC converters, power supplies, and other applications require. In home automation applications, power supply capacitors should exhibit many of the following positive characteristics:

  • High capacitance retention at high frequencies
  • Low failure rate
  • Wide voltage range
  • Surge robustness
  • Environment (moisture/temperature) resistance
  • Low cost

Power designs require protection against transient voltages. Using a capacitor is a common technique to control transients and protect the circuit in voltage control designs. A capacitor may operate across the line/pin to integrate the voltage and assist in preventing electrostatic discharge (ESD) damage. Engineers often overestimate the performance of a standard multilayer ceramic capacitor (MLCC) because of the capacitor’s significant value drop in case of an applied ESD event. The introduction of supercapacitors, in the place of MLCCs, will actually make a design more robust.

Sensing
Electronic systems allow security and monitoring systems to respond in changing situations, conditions and contexts. Sensors may signal door and window motions, smoke or CO presence, physical disturbances, pressure changes, and more. These connected sensors offer a wide range of uses in smart home security and automation applications. Whether through specific sensor components and the related op-amps employed to enable battery-powered wireless devices or through ESD protection for high-speed signal lines, engineers require a range of products to safeguard their designs. Now, we will examine how sensor components and related solutions lead to excellent security monitoring design.

Sensor devices provide real-time system protection, feedback control, and high accuracy system monitoring. Position sensors enable engineers to determine absolute and relative positions, including angles, presence, proximity, distance, flow, level and velocity. Light and image sensors and sensing analogue front ends (AFE) help designers capture a broad range of wavelengths.

Because the human eye cannot be watching everything, it is helpful to have another set of eyes at your home to ensure extra protection. One option a designer might consider employing is an ambient light sensor. This measures the intensity of visible light. The spectral response of the sensor tightly matches the photopic response of the human eye and includes significant infrared rejection (Figure 3).

Figure 3: Automated security entry systems on the gatepost of a house offer an additional set of eyes for a home owner’s protection (Source: Getty Images)

Still, looking for home intruders is not the only sensing function required in many security monitoring systems. Often a change in the ambient environment warrants monitoring. A change in humidity may indicate that an environmental shift is in progress, which may cause significant damage to valuables within a monitored location. In such a situation, a humidity sensor may do the job. Humidity sensors can provide excellent measurement accuracy at very low-power levels and may also include an integrated temperature sensor.

In isolation, sensors alone may not be able to complete the job. Often, they need a signal boost using amplifiers so that downstream electronics can further manipulate and evaluate the sensors’ electronic information. Ultra-low-power, operational amplifiers are used in sensing applications with battery-powered, wireless, and low-power wired equipment. Such ultra-low-power, operational amplifiers help to reduce power consumption in equipment like carbon monoxide (CO) detectors, smoke detectors, and passive infrared (PIR) motion detectors where operational battery life is critical.

Command and control
At the core of any home automation security and monitoring application, there is a need to have command and control over the electronic signals. A proper command and control system allows home owners to achieve greater energy and operational efficiency in the system. By incorporating products and technology with the brains to better monitor and regulate systems, including lighting, windows, doors, video cameras, and more, a home becomes more safe and secure for its occupants.

An effective way to use the command and control functions is to have a controller—specifically, a microcontroller unit (MCU). Microcontrollers are useful in embedded devices, as they contain the processor, memory and peripherals in one integrated unit. Many of today’s MCUs excel at ultra-low-power sensing and measuring. They allow designers to use a command and control platform from which to coordinate their design requirements. Since they possess internal memory, both random access memory (RAM) and read-only memory (ROM), MCUs are well positioned to deliver fast, flexible and reliable command and control functions without requiring additional off-chip capabilities. Onboard memory and peripherals help MCUs minimise their total power consumption.

Communications
Home automation security and monitoring applications are being driven by the increasing need for wireless connectivity to accommodate the Internet of Things (IoT), and hence require a new dimension of wireless connectivity security. Upon authorisation, only where appropriate, data must undergo proper protection by allowing the right send and receive transmissions.

In home automation security and monitoring designs, wireless MCUs, which fully support Bluetooth, ZigBee, low-power wireless personal area networks (LoWPAN), Thread, Wi-Fi, sub-1GHz, Sigfox, or other protocols, must by design provide highly secure, cloud-ready solutions for IoT accessibility. Additionally, wireless MCUs require an input voltage filtering/decoupling network and an output impedance matching network for the radio frequency (RF) antenna.

Today, wireless MCUs can offer designers access to distinct wireless protocol modes. Wireless MCUs may offer a blend of long/robust range, low power and high data rates. By design, they often consume very low amounts of power, allowing for battery operation. They may come with sensors that help them recognise when they should be active and communicating or when they should be in a sleep or wait state.

Wireless MCUs give engineers greater flexibility, as they can then consolidate the command and control functions with the communication functions, ultimately to offer high levels of integration. Such levels of integration will simplify designs and ensure continuously reliable communication.

Security and monitoring in the field of home automation continues to evolve. New electronic designs and solutions continue to accelerate this trend. Now that many homes are automated, smart, and connected, electronic designers need to continue to offer improvements on issues related to power, sensing, command and control, and communications. A design engineer’s imagination is never automated. Consider how your imagination visualises the future, and continues to make our homes more convenient, secure, and safe.

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