8/74 IoT MOOC Part I: Electronics. Sensors in IoT Applications


Hello, my name is in a Leopoldo
Armesto and this presentation I’m going explain about sensors that we
typically use in IoT applications. So, this is the outline of our
presentation so we’re going to explain you about: light
sensors, temperature sensors, moist sensor, rain
sensor also gas sensor, barometric
pressure sensors and finally we are going to explain
also about the radiation sensor and many other
alternatives too The light dependent resistor
also known as LDR is a resistance [resistor] that varies
depending on the amount of visible light received, so typically we
use the sensor to measure the light in our home
or in a greenhouse and we typically need not
just simply the.. the the resistance[resistor] provided by the
LDR but also resistance [resistor] system so it acts as a voltage divider
as you can see here in the in the circuit application. Here
you can see also the… the one of the most known a modules
which is the KY-018 which already
provides all necessary electronics and three pins for
proving the power supply, the ground and the signal itself. It
might require calibration because the relation between
the voltage and the luminance is nonlinear but this depends on
your application if you really want to measure the luxes,
then you need to calibrate it. and… that a it’s a
different procedure… Then, we have a different
kind of temperature sensors we
have the DHT11 which is a digital sensor
and provides the humidity and the temperature in sensors
and with degree precision so it’s not a under
degree and this uses one digital signal for
transmitting and receiving data and here we have
we can find the Keyes module the
KY-015 which provides again three-pins for for power,
ground and the signal itself. Also, we have
the LM35 sensor which is an analog
temperature sensor and the main characteristic is that it
provides a linear response so it has a
resolution of 10mV/C degree and precision
quite small so it means… [sorry]
the precision is high means that they in the resolution
between one measurement another one it’s even 0.5C on has an acceptable range from
all the kind of applications of we want to deploy. Also
we can find the sensor from Dallas company
which is called 18B20, it uses a specific interface
which is called 1-wire interface This interface allows us to put
an several sensors just simply use one wire bus and it measures Celcius and
Kelvin degrees and also provides handlers for a alarms.
Here you find also the… the Keyes module
which is the KY-001 Then, we have the moist sensor.
So, we use the sensor to mea… to measure the
humidity of the soil so it’s it’s simply an
analog output, it provides an analogoutput so this and
signal is proportional to the resistance of
changes of…of the soil moist and also together with the…
the provided electronics we have also digital output
so we have a potentiometer that we can adjust and depending
on the value we set there is analog comparator
in which we can have some kind of threshold
and this… we can use this digital output so whenever the
humidity is above or below that value the digital output will
be HIGH or LOW correspondingly So, we have also a rain
sensor. Is very similar to the previous one the
difference is that we have a panel, this panel,
in which basically it’s providing some kind
of short-circuit/resistance so depending on the amount
of rain and that… that you are receiving, and also provides
the analog output and the digital output interface so the analog
output is proportional to amount of raindrops that you
are… you’re getting with this… this sensor and the
digital output can be activated deactivited depending on
the… the potentiometer value. So then, we have a different
kind of sensors they are called MQ gas sensors they are
different type of sensors depending on the gas that
we would like to detect There are many type of gases
that they’re able to detect LPG, butane, propane, methane,
alcohol, humes, etc… and the basic principle
is that they have some kind ofaluminum
oxide ceramic tube and sensitive
layer and… it has an electrode and a heater
so it needs some time, before its operational and reaches
the appropriate temperature to really measure and the
appropriate measurement it is very interesting to
mention that this kind of sensors they just simply provide an
analog output based on this… on the… on the… on the
received amount of particles of gas that you are detect.
And, if you really want to measure a specific
gas in particles per million then you need
a calibration procedure in which you need to
basically calibrate it first with [on] a
clean air environment. Then, we have also the
barometric pressure sensor It’s able to measure the
absolute pressure of air and provides ranges
between 300 and 100… 1100 Pascals and it provides also the
altitude and the temperature and the altitude depends
or you can set the altitude depending on your location and
the nice or the interesting thing here is using
an I2C interface so it uses basically
two signals. also we have the radiation
sensor with this sensor so we can measure
the ultraviolet light and in this specific
sensor, the GUVA-S12SD, it has a analog
interface and provides measurements light
ranges between 240nm and 370nm. And… there’s an
equivalence between the measured value
and the UV-index so we can use this
sensor as a way to measure the kind of radiation we
receive in our… in our environment. And, obviously, there are many
other kind of sensors that we can use in IoT
applications like RFID car readers, camera
or different kind of in contact or barrier sensors
too. Ok, but this presentation was intended to describe
the kind of sensors that we can use in our home
automation or our greenhouse or weather station projects. Ok,
so thank you very much for your presentation [attention]
we are I hope to see you in my next presentation
too, thank you.

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