MODULE-2
IOT Sensing and Actuation
1 Introduction
➢ The basic science of sensing and actuation is based on the process of transduction.
➢ Transduction is the process of energy conversion from one form to another.
➢ A transducer is a physical means of enabling transduction.
➢ Transducers take energy in any form (for which it is designed)—electrical, mechanical,
chemical, light, sound, and others—and convert it into another, which may be electrical,
mechanical, chemical, light, sound, and others.
➢ Sensors and actuators are deemed as transducers.
➢ Example: Public Announcement System
1.1 Sensors
➢ Sensors are devices that can measure, or quantify, or respond to the ambient changes in
their environment or within the intended zone of their deployment.
➢ They generate responses to external stimuli or physical phenomenon through
characterization of the input functions (which are these external stimuli) and their
conversion into typically electrical signals.
,➢ For example, heat is converted to electrical signals in a temperature sensor, or
atmospheric pressure is converted to electrical signals in a barometer. sensor is only
sensitive to the measured property only.
➢ It is insensitive to any other property besides what it is designed to detect. (e.g., a
temperature sensor does not bother about light or pressure while sensing the
temperature).
➢ a sensor does not influence the measured property (e.g., measuring the temperature
does not reduce or increase the temperature).
Simple outline of a sensing task:
, 1.2 The various sensors can be classified based on:
➢ 1) power requirements,
➢ 2) sensor output, and
➢ 3) property to be measured.
Power Requirements:
➢ The way sensors operate decides the power requirements that must be provided for an
IoT implementation.
➢ Some sensors need to be provided with separate power sources for them to function,
whereas some sensors do not require any power sources.
➢ Depending on the requirements of power, sensors can be of two types.
➢ 1. Active 2. Passive
➢ Active:
➢ Active sensors do not require an external circuitry or mechanism to provide it with
power. It directly responds to the external stimuli from its ambient environment and
converts it into an output signal.
➢ For example, a photodiode converts light into electrical impulses.
➢ Passive:
➢ Passive sensors require an external mechanism to power them up. The sensed
properties are modulated with the sensor’s inherent characteristics to generate
patterns in the output of the sensor.
➢ Example: Thermistor.
➢ Sensor Output:
➢ The output of a sensor helps in deciding the additional components to be integrated
with an IoT node or system.
➢ Digital sensors can be directly integrated to the processors.
➢ Sensors are broadly divided into two types, depending on the type of output generated
from these sensors, as follows.
➢ 1) Analog
IOT Sensing and Actuation
1 Introduction
➢ The basic science of sensing and actuation is based on the process of transduction.
➢ Transduction is the process of energy conversion from one form to another.
➢ A transducer is a physical means of enabling transduction.
➢ Transducers take energy in any form (for which it is designed)—electrical, mechanical,
chemical, light, sound, and others—and convert it into another, which may be electrical,
mechanical, chemical, light, sound, and others.
➢ Sensors and actuators are deemed as transducers.
➢ Example: Public Announcement System
1.1 Sensors
➢ Sensors are devices that can measure, or quantify, or respond to the ambient changes in
their environment or within the intended zone of their deployment.
➢ They generate responses to external stimuli or physical phenomenon through
characterization of the input functions (which are these external stimuli) and their
conversion into typically electrical signals.
,➢ For example, heat is converted to electrical signals in a temperature sensor, or
atmospheric pressure is converted to electrical signals in a barometer. sensor is only
sensitive to the measured property only.
➢ It is insensitive to any other property besides what it is designed to detect. (e.g., a
temperature sensor does not bother about light or pressure while sensing the
temperature).
➢ a sensor does not influence the measured property (e.g., measuring the temperature
does not reduce or increase the temperature).
Simple outline of a sensing task:
, 1.2 The various sensors can be classified based on:
➢ 1) power requirements,
➢ 2) sensor output, and
➢ 3) property to be measured.
Power Requirements:
➢ The way sensors operate decides the power requirements that must be provided for an
IoT implementation.
➢ Some sensors need to be provided with separate power sources for them to function,
whereas some sensors do not require any power sources.
➢ Depending on the requirements of power, sensors can be of two types.
➢ 1. Active 2. Passive
➢ Active:
➢ Active sensors do not require an external circuitry or mechanism to provide it with
power. It directly responds to the external stimuli from its ambient environment and
converts it into an output signal.
➢ For example, a photodiode converts light into electrical impulses.
➢ Passive:
➢ Passive sensors require an external mechanism to power them up. The sensed
properties are modulated with the sensor’s inherent characteristics to generate
patterns in the output of the sensor.
➢ Example: Thermistor.
➢ Sensor Output:
➢ The output of a sensor helps in deciding the additional components to be integrated
with an IoT node or system.
➢ Digital sensors can be directly integrated to the processors.
➢ Sensors are broadly divided into two types, depending on the type of output generated
from these sensors, as follows.
➢ 1) Analog
