Vmoksha IoT Bootcamp for VIT University Professors and Lecturers

Vmoksha organized a 2-day Hands-on IoT Bootcamp for University Professors and Lecturers at Vellore Institute of Technology, Tamil Nadu.

About VIT

VIT University was founded in 1984 with the aim of providing quality higher education on par with international standards. It currently offers 62 degree programs to over 29,000 students in its 2 campuses at Vellore and Chennai. They are among the Top Universities in the country with the quality of their Teaching, Learning, and Research.

Why VIT chosen Vmoksha?

Dr. Rajashekara Babu, the Program Manager of SCOPE (School of Computing Science and Engineering), VIT has attended the 2-day Vmoksha IoT Bootcamp in January at our Bangalore office. He admired the splendid training program we provide with the requisite hardware and software platform during the hands-on sessions.  He had also analyzed other IoT Training institutes and ascertained that Vmoksha IoT Bootcamp is the best among the top IoT training institutes with the high-grade infrastructure and lab facility. He then approached us back to provide IoT training to the other Professors and Lectures of the VIT University.

IoT Bootcamp Sessions at VIT

A group of 7 members from the Vmoksha’s IoT team has reported at VIT campus on the previous day of the bootcamp and arranged all the infra setup for the next two days. On the first day, Dr. Arun Kumar, the Dean of SCOPE, initiated the bootcamp delivering few words on IoT and the importance of the bootcamp. Dr. Rajashekara Babu shared the experience of his last visit to Vmoksha Bangalore Office.

The bootcamp is tailored to the needs of VITians, focusing on the hands-on sessions on industry standard IoT product prototype hardware board ‘LinkIt Smart’ and IoT Software platform, AWS IoT. By the end of the program, the participants implemented an End-to-End, Smart City IoT use case.

There were about 20+ attendees for the session, and many of them have shown a keen interest in knowing Vmoksha real-time projects. Even though the VIT team was quite new to IoT and hardware practice, they have actively taken part during the hands-on sessions.

Some of the major sessions include the discussion of the below topics along with hands-on

  • IoT architecture
  • Sensors and actuators
  • Connectivity technologies & communication protocols
  • Cloud, its components, and IoT
  • Design principles

Vmoksha also provided a custom-designed IoT starter kit to the participants that include all necessary components to kick start the IoT journey. They admired our IoT hardware kit and aspired to setup an IoT lab for their college students. The team was happy with the bootcamp sessions and referred us to the School of Electronics Engineering (SENSE), VIT.

We would like to express our appreciation and sincere thanks to VIT team for their strong support and hospitality during the visit.

VIT University




6 Scenarios for Testing Beacon Integrated Application
Beacon Testing

What is Beacon?

Beacons are small Bluetooth-powered radio transmitters that can trigger real-world actions by relaying contextual information to nearby smart devices.

Beacon Identifiers

The parameters UUID, Major, and Minor are the Beacons identifiers. These parameters together makeup iBeacon’s unique identifier and plays a key role in beacon deployment.

  • UUID: The purpose of the UUID is to distinguish beacons in your network from all other beacons in networks outside your control.
  • Major: The major field identifies and distinguishes a group, for example, all beacons in on a certain floor or room in your venue could be assigned a unique major value.
  • Minor: The minor field identifies and distinguishes an individual beacon, for example, distinguishing individual beacons within a group of beacons assigned a major value.

Beacon Application Developed by Vmoksha

Vmoksha developed a beacon integrated iOS application that assists users to discover the nearest meeting room in their office on preferred date and time.

How does it work exactly?

Beacons were fixed in the meeting rooms. We have assigned a single UUID to the group. It will notify users the nearest available meeting rooms first just by referencing the UUID. The application developed scans for beacons and displays the availability of rooms with date and time. The user should choose and book the convenient room and can invite people from the contact list to the meeting.

Android iBeacon


  • App installation on the iOS device
  • Beacons to place/fix in the meeting room (Used Kontakt beacons)
  • Internet connectivity should be on
  • Bluetooth (BLE) has to be activated in the mobile device

Testing the Beacon Application

For testing the application, we used two beacons to book the meeting room either by date and time or availability of particular meeting room.

Search by date and time: The app allows a user to set the time slot of a meeting for a minimum of 15min with no maximum limit. When we set the preferred date and time in the app, the app displays a list of rooms with the nearest room first, followed by the succeeded one.

Search by availability: The app allows users to search for availability of a particular meeting room and enables them to book that room when it is unoccupied.

To test the beacon application, we followed the following steps:

  1. Installed the app on multiple iOS devices (iPhone 6, 6+, iPad)
  2. Attached  beacons  to different rooms
  3. Followed various test scenarios

We have followed several scenarios while testing the application. Here, I have mentioned the major 6 test scenarios that we followed during the testing.

Scenario 1: Book a room based on date and time and send invite

Case 1: Device connected to Wi-Fi and Bluetooth

  • Select the date and time
  • The app displays a list of rooms with the nearest room first
  • Select the room and invite people to attend meeting

Result: App should allow booking of a room and inviting people

Case 2: While booking the room, disconnect mobile device from the Wi-Fi

Result: App should display the error message ‘please check the network connectivity’

Case 3: While searching the room, disconnect the Bluetooth connectivity

Result: The app should display an error message as we need Wi-Fi to get the status of the meeting rooms and availability. BLE is required to navigate and identify the meeting room using Beacons.

Scenario 2: View rooms based on available timings of the specific room and send invite

  • Connect device to Wi-Fi and Bluetooth
  • Select the ‘search by available meeting room’
  • The app displays the available timings of the specific room with the nearest room first
  • Select a room and invite people to attend meeting

Result: App should allow booking of a room and inviting people

Scenario 3:  Book a room that was already booked

  • Connect the device to Wi-Fi and Bluetooth
  • Book the ‘room 1’ on May 10th, 2017 @10:00 A.M
  • Again try to book the same room for the same date and time

Result: In the available room(s) list, it should not display the ‘room 1’

Scenario 4: Book a room for the past /present/future date and time

Case1: Book a room for the past date and time

Result: App should not allow the booking of a room for the past date and time

Case 2: Book a room for present date and time

Result:  App should allow the booking for present date and time

Case 3: Book a room for future date and time

Result: App should allow the booking for future date and time

Scenario 5: Book a room while mobile is in airplane mode

  • Connect the device to airplane mode
  • Make sure the device is connected to Bluetooth and Wi-Fi
  • Book a room either by Search by date and time or Search by available room options

Result: App should allow the booking of a room

Scenario 6: Book a room when mobile battery is draining (charge less than 20%)

Result: App should allow the booking of a room


  1. At times, the nearest available room was showing next in the availability list.
  2. Beacons not working:
    • Battery is not properly placed
    • Battery might be discharged

3. User calendar is not mapped to the app to see whether he or she is available to send the invite.


Beacon is a low cost, low powered and low energy Bluetooth device that uses low-frequency for transmitting weak signals to other Bluetooth-enabled devices. When people pass through the beacon integrated meeting room the app will detect the nearby available meeting room.

Over 200 Participants Were Trained at Vmoksha IoT Bootcamp


We are glad to share that Vmoksha has successfully completed its 17th IoT Bootcamp. On completion of this Bootcamp, we have passed an important milestone i.e. over 200 participants were trained at our IoT bootcamp. This has empowered us to train more participants effectively in the future. We would like to thank every participant for their enormous support.

All our bootcamps were assembled by participants from absolute beginners to the technical professionals from various domains such as Engineering, Medical science, and Management. We are elated to find that our training has helped candidates in developing their knowledge and skill to excel in their professional life as well as enabled them to develop IoT solutions on their own. Overwhelming with the response from participants, we have included a one-day additional session to our regular 2-day bootcamp that demonstrates IoT & WSN (Wireless Sensor Network) based on the candidate’s preference. We have also started online IoT training for the participants’ convenience.

Vmoksha is currently one of the best IoT Training providers as per the attendees. Click Here to know what our participants say about Vmoksha IoT Bootcamp.

Vmoksha at IoT SHOW INDIA 2017 – Profit From IoT

We never miss an opportunity that can augment our business network. IoT SHOW is one such opportunity for Vmoksha to meet 3000+ delegates from IoT domain.

The event was organized at Bangalore by EFY group with the support of Ministry of Electronics & Information Technology, India. It was a 3-day event, where the participants will get to see cutting-edge IoT components, solutions, and technology as well as meet engineers who create amazing products. As suggested by the tagline, “Profit From IoT,” the event benefits all the stakeholders with valuable insights gathered from the most popular vendors of IoT components that will help them in developing viable IoT solutions.

There were several seminars from industry experts, which helped us in acquiring deep-domain knowledge of IoT that aids in nurturing Vmoksha’s IoT practice with a lot of creative and innovative ideas.

Few of our favorite sessions:

  • An interesting session on “AI and Medicine,” which gave insights on current happenings in AI to deliver personalized medicine.
  • IoT forensic session focusing on IoT security, which is a key concern and revealed how other players are handling the concerns.
  • A session on edge computing (Fog Computing) was helpful.

We have also met Mr. Ganesh Shankar, CEO of FluxGen, who has established a working relation on an interesting solution called “Smart Solar panel.”

The IoT SHOW is an excellent platform for major exposure to IoT stakeholders and to interact and understand peers and prospects better.


Our Vice President and Mobility & IOT Practice Head at IoT SHOW


Sensor Characteristics

The sensor is a transducer that converts a physical property into an electrical signal. The physical property can be Weight, Temperature, Pressure, Percentage Composition, Force, Electric or Magnetic or Electromagnetic, Position and Orientation, etc.

The sensors are classified as active sensors and passive sensors based on their working principle. The active sensors use an external or self-generated signal to measure. For example, RADAR emits a series of intense radio waves for a short time and waits for the radio waves or signal to return and calculate the distance of the distant object using the signal flight time. The passive sensors work by changing their electrical properties like resistance or capacitance based on the physical property. For example, an LDR changes its resistance based on the intensity of light.

Sensors must have the following significant properties to define the quality of a sensor:


Every sensor has a range in which they work with an acceptable error. If the input is not in range, then the output is unpredictable.


The signal level varies for the same input over a long period; this is called as drift. The drift will cause an error in the measured value. The drift may result from aging of the sensor or temperature variance.


Sensitivity is defined as the change in output per unit change in input of the property being measured. The sensitivity of the sensor may be constant or linear for the entire range of sensor or vary exponentially if the sensor is a non-linear sensor


Selectivity is the ability of the sensor to measure a target property in the presence of other properties. For example, if an oxygen sensor does not react to other gasses like CO2 then it has good selectivity.


The resolution of a sensor is the minimum change in the target property that can produce a detectable change in output. For example, consider a temperature sensor with a resolution of 1C; this temperature sensor cannot produce a different output for 0.1C change in input.

Response and Recovery Time

The response time is the time taken by the sensor for its output to reach 95% of its final value when it is exposed to a target material. The Recovery Time is defined conversely.


If the sensitivity of the sensor is constant for the range, then it is called as linearity of the sensor. The linear sensors are easier to use while the non-linear sensors require complex mathematical equations to measure the physical property.


The hysteresis is the characteristic of a sensor by which the sensor produces a different set of outputs if the data is recorded in different directions (increasing input or decreasing input). The hysteresis can be observed in the following figure:



If a meaningful measurement is to be made, it is necessary to tune the output of the sensor with accurately known input.

Full-Scale Output

The full-scale output is the difference between the output for maximum input and the output for minimum input. Based on this, the ADC’s reference voltages have to be selected properly.


The precision of a sensor is its ability to produce same output when repeatedly measured for the same input. The precision is determined using statistical analysis standard deviation.


The accuracy of a sensor defines how close the output is to the real value. The accuracy defines the maximum error the sensor may produce.

sensor-characteristics Accuracy




Wireless Protocols for Internet of Things

If you are planning to do an IoT project, you need to take decisions on sensors or actuators to use, hardware for edge device( node), and hardware for Gateway (Gateway connects your node to the internet). For communication, decisions should be made on wireless protocol (Node to Gateway), Network Protocol, Communication Channels (gateway to the cloud), and IoT cloud platform to be used.

In this article, I will be briefly discussing wireless communication protocols that are widely used in IoT scenario. For each protocol, a brief description of the protocol followed by Pros & Cons, technical features, application areas, and website link for further exploration are given.


Wi-Fi – Wi-Fi Alliance

Wi-Fi- Wi-Fi Alliance


Wi-Fi is a technology developed for electronic devices to connect to a wireless Local Area Network (WLAN). Wi-Fi uses the 2.4 gigahertz (12 cm) UHF and five gigahertz (6 cm) SHF ISM radio bands. The Wi-Fi Alliance defines Wi-Fi based on the IEEE 802.11 standards. It has various encryption technologies WEP, WPA, WPA2, etc., and is password protected. However, it can be used as open Wi-Fi without any password, which allows any device within its range to access the resources of the WLAN network.

Wi-Fi technology has been used widely; this allows utilizing the current infrastructure for the new Internet of thing technology.

Wi-Fi Description

Standard: Wi-Fi Alliance

Frequency: 2.4 GHz, 5.8GHz

Range: 10-100 m

Data Rates: 11-105 Mbps

Application Focus:

  1. Residential & Commercial IoT router
  2. Smart traffic management
  3. Office automation

Reference URL, Wi-Fi - http://www.wi-fi.org/


Bluetooth – Bluetooth SIG

Bluetooth SIG


Bluetooth is a wireless technology IEEE 802.15.1 standard-based protocol for data exchanging. Initially, Bluetooth was developed for wire replacement of computer and mobile peripherals. Bluetooth uses short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz, especially for personal area networks (PANs). The Bluetooth specification is managed by the Bluetooth Special Interest Group (SIG). Bluetooth is not suitable for IoT scenario as it consumes more power.

Bluetooth SIG Description

Standard: IEEE 802.15.1

Frequency: 2.4 GHz

Range: 10-30 m

Data Rates: 723 Kbps

Application Focus:

  1. Cable replacement
  2. Personal useriInterface
  3. Simple remote control
  4. Browse over Bluetooth

Reference URL, Bluetooth - https://www.bluetooth.com/


Bluetooth Low Energy (BLE) – Bluetooth SIG

Bluetooth Low Energy


Bluetooth low energy (Bluetooth LE, BLE, and Bluetooth Smart) is a wireless personal area network technology similar range to Bluetooth. BLE is designed to work with low power consumption and is inexpensive. Like Bluetooth, BLE also has specification managed by the Bluetooth SIG.

BLE is designed by the Bluetooth SIG for low-powered devices that use less data. BLE goes to sleep when not in use and wakes up when data transfer happens. This makes it ideal for IoT device, which runs on battery and consumes low power.

The BLE modules available in the market implements a mechanism called “Dual Mode” that will make the device work with Classic Bluetooth as well as a BLE device.

Standard: Bluetooth SIG

Frequency: 2.4 GHz

Range: 200ft

Data Rates: 25Mbps

Application Focus:

  1. Mobile phones
  2. Smart homes
  3. Wearable’s
  4. Automotive
  5. Healthcare
  6. Bluetooth payment
  7. Network availability
  8. Heart rate monitor
  9. Sports & fitness, etc.

Reference URL, Bluetooth Low Energy (BLE) - https://www.bluetooth.com/what-is-bluetooth-technology/bluetooth-technology-basics/low-energy


ZigBee – Zigbee Alliance


ZigBee is an IEEE 802.15.4 standard-based protocol for personal area network with short range, low power, and low data rate wireless data transfer.

ZigBee is simpler and less expensive than other wireless personal area networks; ZigBee has some advantages over other wireless protocol such as low-power operation, high security, robustness and high scalability for wireless control and sensor networks IoT applications. ZigBee devices can transmit data over long distances by a mesh network passing data through intermediate neighbor devices to reach more distant. Zigbee IoT Applications include wireless ZigBee Smart Energy, Home Automation, and light switches.

Standard: IEEE 802.15.4

Frequency: 868/915 MHz – 2.4 GHz

Range: 10-300m

Data Rates: 250 Kbps

Application Focus:

  1. Monitoring & Control
  2. Commercial & Industrial
  3. Home and Building Automation
  4. Medical Data Collectio
  5. Wireless Sensor Networks

Reference URL ZigBee - http://www.zigbee.org/


Z-wave – Z-Wave Alliance


Z-Wave is a wireless technology that lets smart devices talk to one another. The Z-Wave protocol is primarily designed for home automation. Z-wave is optimized for reliable and low-latency communication of small data packets with data rates up to 100kbit(s) and operates in the sub-1GHz band. Z-wave is simple compared to other protocol that makes it easy and faster for development.

Z-wave has full mesh networking capabilities without the need of a coordinator node and is very scalable, enabling control of up to 232 devices.

Standard: Z-wave

Frequency: 900 MHz

Range: 100 m

Data Rates: 10-100 Kbps

Application Focus: 

  1. Control and automation
  2. Home Automation
  3. Simple Remote Control
  4. Gaming
  5. Medical Applications

Reference URL Z-wave - http://www.z-wave.com/


6LowPAN – IETF, Google


6LoWPAN stands for IPv6 over Low power Wireless Personal Area Networks. 6LowPAN is a network protocol that defines header compression and encapsulation mechanisms allowing IPv6 packets to be sent and received over IEEE 802.15.4 based networks. The 6LoWPAN is specifically developed for low-power devices with limited processing capabilities, which can be able to participate in the Internet of Things. 6LoWPAN is the name of a concluded working group in the Internet area of the IETF.

Standard: IEEE 802.15.4

Frequency: 2.4 GHz

Range: 200 m

Data Rates: 200 Kbps

Application Focus: 

  1. 6LowPan Smart Meters
  2. Smart Lighting
  3. Thermostats
  4. Smart Grid
  5. Wireless Sensor Networks
  6. Industrial Automation
  7. Advanced Traffic Management System

Reference URL 6LowPAN - https://datatracker.ietf.org/wg/6lowpan/documents/




Radio-frequency identification (RFID) uses electromagnetic fields. RFID is not new since it has been used almost in every industry to identify and track tags attached to objects automatically. The tags stores information electronically. There are two types of RFID tags, Active and Passive. Passive tags collect energy from RFID reader’s radio waves whereas Active tags have its power source such as a battery and can operate at hundreds of meters distance from the RFID reader. RFID technology can be used in the IoT to identify objects and link them to the Internet.

Standard: ISO RFID standards, EPCglobal standards

Frequency: 120 KHz – 150 KHz, 13.56 MHz, and 433 MHZ

Range: 10 CM to 100M

Data Rates: 10-100 Kbps

Application Focus:

  1. Access management
  2. Tracking of goods
  3. Tracking of persons and animals
  4. Toll collection and contactless payment
  5. Machine readable travel documents
  6. Smart dust (for massively distributed sensor networks)
  7. Electronic Lock with RFID Card System
  8. Tracking sports memorabilia to verify authenticity
  9. Airport baggage tracking logistics
  10. Timing sporting events

Reference URL RFID - http://rfidinc.com/




Near Field Communication (NFC) technology is used for communication between two NFC-enabled electronic devices like Smartphone. NFC communication uses electromagnetic induction between two NFC loop antennas located between near field, which effectively forms an air-core transformer. NFC operates unlicensed radio frequency ISM band of 13.56 MHz on ISO/IEC 18000-3 air interface. NFC working involves two participants, an initiator, and a target; the active initiator generates an RF field that can power a target that is passive (“NFC tag”). NFC comes in very small factors such as tags, stickers, and key fobs. NFC peer-to-peer communication is possible when provided by both devices are powered. NFC technology allows IoT device’s contactless data transfer.

Standard: ISO/IEC 18000-3

Frequency: 13.56MHz

Range: 4 cm

Data Rates: 100–424kbps

Application Focus: 

  1. NFC contactless payment
  2. Wearable baby monitors
  3. Smart marketing posters
  4. E-Commerce
  5. Bootstrapping other Connections
  6. Identity And Access Tokens
  7. Gaming

Reference URL NFC - http://nfc-forum.org/


Thread – Thread Group


The thread is built on IEEE 802.15.4 based 6LoWPAN wireless protocol with mesh communication. The thread is a low-power, secure and scalable IP-based wireless mesh networking protocol. Thread networking provides self-healing mesh networking with over 250 nodes and support for sleepy nodes, allowing years of operation from a single battery.

The thread was launched by thread group in 2014. Thread group Alliance today working with the companies Nest Labs, Samsung, ARM Holdings, Qualcomm, NXP Semiconductors/Freescale, Silicon Labs, Big Ass Solutions and OSRAM. The thread is IP-addressable and can have direct access to cloud and AES encryption. The thread is specifically designed for home automation setup.

Standard: IEEE802.15.4 and 6LowPAN

Frequency: 2.4 GHz

Range: N/A

Data Rates: N/A

Application Focus: 

  1. Connected home
  2. Home Automation
  3. Consumer utility

Reference URL Thread - http://www.threadgroup.org/


LoRaWAN – LoRa Alliance


LoRaWAN is a Low Power Wide Area Network (LPWAN). LoRaWAN is a media access control (MAC) layer protocol designed for public networks in large-scale with a single operator. It is built using Semtech’s LoRa modulation as the underlying PHY. LoRaWAN used for secure mobile bi-directional communication in wireless battery operated devices. LoRaWAN is ideal where low power and long range is needed with millions and millions of devices connected.

Standard: LoRaWAN

Frequency: Various (eg 902MHz -928MHz)

Range: 2-5km (urban environment), 15km (suburban environment)

Data Rates: 0.3-50 kbps

Application Focus: 

  1. Ideal for smart cities
  2. Environmental data monitoring

Reference URL LoRaWAN - https://www.lora-alliance.org/What-Is-LoRa/Technology


Sigfox – SIGFOX


Another wireless wide range technology is Sigfox which comes with a range between Wi-Fi and cellular. Sigfox uses free ISM band to transmit data over the very narrow spectrum. Sigfox is designed to handle low data-transfer speeds of 10 to 1,000 bps using an Ultra Narrow Band (UNB) technology. Sigfox overcomes the problem of Wi-Fi and cellular in many applications that has short Wi-Fi range, where cellular cost is high and consumes more power.

SIGFOX is a French company that builds wireless networks, which is founded in 2009 by Ludovic Le Moan and Christophe Fourtet. Typically, it is an internet of thing device that needs to transmit continuously in small amount data. Best use cases for Sigfox are electricity meters, smart watches, and washing machines.

Standard: Sigfox

Frequency: 900MHz

Range: 30-50km (rural environments), 3-10km (urban environments)

Data Rates: 10-1000bps

Application Focus:

  1. Smart meters
  2. Patient monitors
  3. Security devices
  4. Street lighting
  5. Retail including point of sale, shelf updating, etc
  6. Environmental sensors

Reference URL Sigfox - http://www.sigfox.com/


Selection of a Wireless protocol for an IoT Project needs a clear understanding of the use case as it needs to satisfy the requirement.

Working with MQ2 Gas Sensor


The MQ-2 Gas Sensor module detects gas leakage in home and industry. The MQ series of gas sensors use a small heater inside with an electrochemical sensor. They are sensitive to a range of gasses and are used indoors at room temperature. The output is an analog signal and can be read with an analog input of the Arduino.


  1. Wide detecting scope
  2. High sensitivity and fast response
  3. Long life and stable
  4. Simple drive circuit


Due to its fast response time and high sensitivity, measurements can be taken as soon as possible. The sensor sensitivity can be adjusted by using the potentiometer.


They are useful in gas leakage detection of LPG, propane, methane, i-butane, alcohol, Hydrogen, and smoke.

Working Principle

The MQ2 has an electrochemical sensor, which changes its resistance for different concentrations of varied gasses. The sensor is connected in series with a variable resistor to form a voltage divider circuit (Fig 1), and the variable resistor is used to change sensitivity. When one of the above gaseous elements comes in contact with the sensor after heating, the sensor’s resistance change. The change in the resistance changes the voltage across the sensor, and this voltage can be read by a microcontroller. The voltage value can be used to find the resistance of the sensor by knowing the reference voltage and the other resistor’s resistance. The sensor has different sensitivity for different types of gasses. The sensitivity characteristic curve (Fig 2) is shown below for the different type of gasses.





1. Ro is the resistance of the sensor in clean air

2. Rs is the resistance of sensor when exposed to gasses

Procedure to Calculate the Concentration of a Particular Type of Gas

To find the concentration of gas, two values has to be measured using a microcontroller with ADC such as Arduino,

1. Ro – The resistance of the sensor when measured in clean air,

2. Rs – The resistance of the sensor when it is exposed to any of the mentioned gasses

To find Ro, connect the sensor to one of the Analog pins of Arduino, note 100 values, and select the median value. This will reduce if any dynamic errors present in the values. The sensor is connected in the series with a variable resistor (Potentiometer on the sensor board). So, to find the resistance of the sensor (Ro or Rs), the resistance of the variable resistor (R1) is required. In most of the MQ2 sensor modules, any one end of the potentiometer and the middle pin of potentiometer will be connected between Sig or Vout Pin and Ground. Find the resistance of R1 using a multimeter and note it down.

The voltage across the sensor Vs (Vs is Vo in Clean Air) is calculated by using the following formula:

Vs=VRef – ADC_Value * (VRefH-VRefL)/(2R)


VRefH is the higher Reference voltage of the ADC, in Arduino, it is usually 5V or 3.3V

VRefL is the lower reference voltage of the ADC, in Arduino, it is usually 0V

R is the resolution of the ADC, in most of the Arduino boards, it is 10 Bits

Once the voltage across the sensor and value of R1 is known, the resistance of the sensor can be calculated by using the formula

Ro=R1 Vo/ (VRef-Vo)

Where Vo is the voltage across the sensor in clean Air

Similarly, the Resistance of the sensor when exposed to gas can be calculated by repeating the above steps and using the formula

Rs=R1 Vs / (VRef-Vs)

Where Vs is the voltage across the sensor in the Air contaminated with LPG molecules

Note: The value of R1 is only for finding the value of Rs and Ro. For finding the concentration of gas, R1 is not required as the concentration is dependent on the Rs/Ro ratio. R1 is not required for finding just the ratio.

Finding the Concentration of a Gas

The concentration of a gas can be calculated by measuring the sensor’s Ro and Rs values and using the following formula

Concentration = Xo (Y/ Yo) Φ

Where Φ is the slope, which can be found using the Sensitivity Characteristic curve and the following formula

Φ = Log (Y2/Y1) / Log(X2/X1)

Where (X2, Y2) and (X1, Y1) are any two points on a section (lines between indicated points on the curve) of the curve. Since the curve has different slopes at different concentrations the (X2, Y2) and (X1, Y1) values should be taken from the corresponding sections

The Xo and Yo values are Initial Concentration and Rs/Ro ratio on a section of the curve (lines between marked points), these values are the starting points of each section (each line between marked points has different slopes)

Y is the Rs/Ro Ratio for the current concentration of the gas

The Arduino code can be found in the below link


To find Ro (Resistance of Sensor in clean air), just run the code in clean air for few minutes (for Accurate values, run it for 24 hours) and note down the resistance in the serial monitor.


A Look at the AWS IoT Ecosystem

The Internet of Things (IoT) enables smart objects to link with various information services that are based on the internet. The IoT cloud platform provides a framework to host applications that link smart objects to internet based services. The IoT cloud platform also provides a way to control smart objects with other smart objects.

AWS IoT is a cloud platform that not only provides an easy way to connect to IoT-enabled devices to the cloud but also can store, analyze and visualize data by making sense out of it.


AWS IoT provides a platform where the sensor grids, aircraft engines, connected cars, factory floors, and the similar things can be connected easily and securely to the cloud and other devices. The cloud connection to IoT devices is fast and lightweight (MQTT or REST), which makes AWS IoT a great fit for devices that have limited processing power, battery life or memory.

AWS IoT Architecture

Let’s take a look at the AWS IoT components:


Things are devices of all types, shapes, and sizes including applications, connected devices, and physical objects. Things measure and control something of interest in their local environment.

Ex: Consider you have a LinkIt One Board to which you have to connect a temperature sensor. The LinkIt One device keeps uploading sensor data to AWS IoT. In AWS IoT, “LinkIt One board + Temperature sensor” represents a virtual device called a “Thing.” Things have names, attributes, and shadows.

1. Thing Name: Unique name given by the user to identify a thing.

2. Thing attributes: The attributes represents the unique features of the thing as the thing serial number etc.

3. Thing Shadows: The shadow represents the current state of the IoT device. The AWS Thing shadow can also be updated by other end devices; this will help us control the IoT-enabled

Example: Consider that there is an IoT-enabled Air conditioner which is constantly sending its current state to the AWS IoT Thing shadow, and assume that the currently reported state of the device is “OFF.”. Now, a user can update the AWS IoT Thing shadow from his mobile phone or laptop and change the desired state (request to change the state) to “ON.” The shadow will compare the “reported state” (reading from the sensor) of the device with the desired state of the device, and if there is a difference between the reported and the desired state, it will send an appropriate response to the device.

Rules Engine

The Rules Engine collects the data sent to the IoT cloud and performs actions based on factors that are present in the collected data and routes them to AWS endpoints like Amazon DynamoDB, AWS Lambda, Amazon Simple Storage Service (S3), Amazon Simple Notification Service (SNS), and Amazon Kinesis. The actions are expressed using an SQL-like syntax. Routing is driven by context and contents of individual messages. For example, routine readings from a temperature sensor could be tracked in a DynamoDB table where as an aberrant reading that exceeds a value stored in the thing shadow can trigger a Lambda function.

Message Broker

The Message Broker implements the MQTT protocol. The Message Broker can scale to contain billions of responsive long-lived connections between things and your cloud applications. Things use a topic-based publish/subscribe model to communicate with the broker. They can publish their state and can subscribe to incoming messages. The publish/subscribe model allows a single device to share its status efficiently with any number of other devices.

Authentication and Authorization

AWS IoT supports mutual authentication and encryption at all levels of connection to end data exchange between AWS IoT and devices without proven identity. It supports AWS method of authentication (called as ‘SigV4’) and X.509 certified based authentication. HTTP connection can use either of these methods while MQTT connection uses certification based authentication, and the WebSocket connection uses Sig v4 connectivity. With AWS IoT, you can use AWS IoT generated certificates or the certificates that are signed by your preferred Certificate Authority (CA).

You can create and deploy certificates and policies for your devices from AWS IoT console or use an API. These device certificates can be activated and associated with the relevant policies that are configured using AWS IAM. Doing this will allows you to revoke access to an individual device instantly if you choose to do so.

Thing Registry

The Thing Registry does the assigning task and allocates a unique identity for each thing. It also helps in the tracking of descriptive metadata like attributes and capabilities for each thing.


With AWS IoT, we can build an IoT end-to-end application, which will collect data from sensors, store collected data, analyze and visualized. The insights we get from the analytics and visualization will help businesses gain efficiencies, improve operations, harness intelligence from an extensive range of equipment, and increase customer satisfaction.

Exploring IoT Through a Use Case

The Internet of Things (IoT) is much more than attaching sensors to things and controlling them through the internet. The concept of IoT holds long-term application capabilities as our day-to-day lives are influenced by smart technologies and people are investing brains to make them a reality, which can only be accomplished by IoT.

Here is an example that explains IoT use case for a logistic company.

IoT Use Case

A logistic company is transporting fish long distances in refrigerated containers. They transport the fish with the utmost care because the fish may spoil if not handled properly during the transit. Also, the company makes an agreement with the merchant that if the fish spoils during transit, then the company needs to compensate the merchant. Therefore, the following parameters are imperative to avoid greater losses.

Temperature: The fish needs to be frozen to maintain its highest quality.

Humidity: Important to avoid thawing of frozen fish.

GPS Location: To track the container.

Door Sensor: To alert the company if the truck door is opened.

Human Presence Sensor: To check any human presence in the container.

The company solved the problem efficiently using IoT technology. They embedded different sensors to the container, which collected and sent data to the cloud for analysis. The sensors help track whether the temperature and humidity are under specified conditions, the container is travelling the specified route, the door is not opened during transit, or there is a human presence in the container. If a merchant makes any claims about the quality of the fish, the company will analyze the data collected and find out the exact reason behind the spoiled fish. Also, the company will be updated with the tracking data at a given period (five minutes, two mintues, etc.) so that they can take immediate action if required.

Let’s consider that the company has not adopted and IoT system. The company might suffer huge losses if a merchant makes any false claims by saying that the fish is spoiled during the transit. Also, the company will not know if there were any changes in the container conditions or location. Therefore, the IoT system will promptly help to address all of the discussed problems before causing any major damage. The IoT process flow for this use case is as follows:

Data Collection: Collects data from sensors placed in the container and sends this data to the cloud.

Rule Engine: When cloud receives data it will check for any alerts to be raised. For example, if the container door is opened it sends alert to the company.

Data Storage and Cleansing: Using Big Data tools, the data will be stored.

Data Analysis: If a merchant raises any claims, the data can be analyzed to verify the claim.

Visualization: Generation of reports from the data.


An IoT-enabled end-to-end application will collect data from sensors, store it, analyze it, and visualise it. The insights we get from the data collected will help to improve the entire system and process, thereby improving the systems operations, transparency, profitability, efficiency, and customer satisfaction.

Security Technologies behind SSL

Since the early age, computers have been used to transmit confidential and sensitive messages. But, sometimes people intercept and use these messages for their gain. Therefore, to safeguard the important messages such as credit/debit card information, different methods of encryption have been implemented.

Cryptography or Cryptology is the study and practice of techniques for secure communication in the presence of third parties called adversaries. In general, cryptography is about constructing and analyzing protocols that prevent adversaries or the public from reading private messages.

Symmetric Encryption:


Symmetric cryptography is a cryptographic system which uses a single key to encrypt and decrypt data. Both the sender and receiver use the same key to communicate.


However, symmetric keys also have a disadvantage. As both the sender and receiver use one key to encrypt or decrypt, sharing the key to each other is difficult. If they have to share the key through the internet, chances are there that a hacker can intercept the key.

Public/Asymmetric-key cryptography: Public-key cryptography, or asymmetric cryptography, is a cryptographic system that involves pairs of keys; public keys can be shared widely pairing with private keys that are known only to the owner. In other words, in a public-key encryption system, anyone can encrypt a message using the public key of the receiver. But, the message can be decrypted only with the receiver’s private key.

Example: John wants to send a secret message to Jane, So he will encrypt these message with a public key (generated by Jane using a key generation program whose input is a large random number and whose output is one public and one private key. The private key secret and is kept by Jane and the public key is spread widely to the public) and sends this message to the Jane even if the message is captured, it cannot be decoded without the private key.


Disadvantages of public-key encryption

  1. The public-key encryption methods are several orders of magnitude slower than the best known symmetric-key schemes.
  2. Key sizes are usually larger than those required for symmetric key encryption. The size of public-key signatures is larger than that of tags providing data origin authentication from symmetric-key techniques.
  3. No public-key scheme is proven secured. The most effective public-key encryption schemes have their security based on the set of number – theoretic problems.
  4. Public-key cryptography does not have a history of symmetric-key encryption.

Which is Stronger?

Both the symmetric and asymmetric encryptions are stronger. When we consider in terms of computational burden and ease of distribution, symmetric encryption requires less computational burden whereas asymmetric encryption involves with ease of distribution.

Digital Certificate:

Digital certificate is the electronic format of physical or paper certificates such as passport, membership card, driving license, etc. It proves your identity or the right to access services or information on the internet. Digital certificates are issued by a trusted authority empowered by law, known as Certifying Authority (CA).

Public Key Infrastructures:

A PKI-based authentication uses hybrid cryptosystem and benefits from using both types of encryption.

Steps Involved in SSL Authentication Protocol


1. A client broker requests a secure page (SSL Hello)

2. The web server sends its public key with its certificate

3. The browser checks whether that certificate was issued by a trusted party (CA), valid or not, and relation to the site contacted


4. The browser creates a symmetric session key and encrypts it with the server’s asymmetric public key. Then sends it to the server.

5. By using the asymmetric private key, the server decrypts the encrypted session and gets the symmetric session key.



6. Server and Browser now encrypt and decrypt all transmitted data with the symmetric session key. This allows for a secure channel because only the server and browser know the symmetric session key, which can only be used for that session. If the browser has to connect to the same server the next day, a new session key would be created.

Applications of SSL:

SSL-secured transactions with e-commerce Web site: It is a typical use case of SSL transaction between a browser and a Web server where the protocol is used to authenticate if the server and then pass the customer’s credit/debit card details to the server.

Authenticated client access to an SSL-secured Web site: Both the client and server need certificates from a trusted certification authority (CA) that they both trust.

Remote access: SSL technology is used to provide authentication and data protection for users who want to log into their system (computer) remotely.

E-mail: The security protocol is used to transmit private communications via the Internet.


Communication using SSL-based encryption and authentication is highly secure with little to no chance that the communication can be decrypted by a hacker thus making software’s/websites highly secure and trustworthy.