Smart City - IoT Based Connected Emergency Response System

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Today we will see one of the fundamental approaches of connecting various edge devices to the internet and thus achieve our first step toward the Internet-of-Things. We will use the following scenario to demonstrate the concept. This post is the opening article (1 of 10 planned posts) for a series in-depth technical (with electronics and code, of course!) articles on this Smart City topic. In this post we will see a detailed overview of WHAT needs to be done. The posts that follow in future, we will take up each technical topic and look at it in details. At the end of this series of posts the idea will be to develop a fully working prototype of the envisaged scenario.

SCENARIO: Smart City - IoT Based Connected Emergency Response System

Imagine a Smart City framework where all public places are subscribed to a central fire alert system. And in turn emergency response services (Fire Department in this example) are alerted automatically. The following diagram is self-explanatory with numbered series of steps (1 through 11) to depict the process flow in case of a Fire emergency. Also in this example we are not using GSM modules, instead we are using the ESP chip and taking the Wi-Fi route. In a furture post I will write about the GSM module in the case of a Wild Forest Fire Early Alarm System.

Figure 1 - Smart City - IoT Based Connected Emergency Response System

For building this system, we will require different categories of things - both hardware and software. In the following section we will see the different types of things that will be required.

Hardware:

• Sensors: MQ2 Series Gas/Smoke Sensor, DHT Series Heat Sensor and LDR based light sensor. This combination of 3 sensors will act as a compound sensor for detecting fire (Smoke, Heat and Light).
• Controller: Arduino UNO (only during the prototyping of the individual sub-units), for the full blown project use Arduino Mega because we will require a lot of GPIOs (General Purpose Input Output Pins) in order to control all the peripheral devices.
• Fire Defence System: Sprinkler fitted with a Solenoid Valve - a Solenoid Valve can be opened and closed electrically, a 12V Optocoupler Relay for switching the solenoid valve ON/OFF, a Piezo Buzzer (for making shrill beeps at high frenquency) and some basic electronics (resistors and transistors - we will see in detail in the following posts).
•  Internet Enabler: ESP8266-ESP01 Wi-Fi chip and AMS1117 3.3V step-down voltage regulator for connecting the Tx Pin (from Arduino) to Rx Pin (of the ESP8266-ESP01). There are atleast 12 versions of the ESP chip, each version comes with its own bells and whistles. For now let us use the basic stuff i.e. ESP01.
• Wi-Fi Router: A Wi-fi network for Internet connectivity.
• Power Source(s): You will need the following 3 types of power sources. One 5V, 1A AC to DC Adapter (for Arduino, Sensors and Piezo Buzzer)and another 3.3V, 60 - 650 mA AC to DC Adapter (for the ESP8266). Use the third power source with "great" caution - AC mains (for the Solenoid Valve via the Optocoupler Relay). 

Software:

• Programming IDE: Arduino IDE - we will use this to write code (using C language), compile and flash (push/embed the C program into the micro-controller).
• Cloud Platform: ThingSpeak/Dweet/Azure IoT Hub. We will use either one of these. The future posts will make the choice. The cloud platform will be used to log the alerts from the edge devices.
• Responsive Web App: HTML5, Bootstrap, CSS3, JQuery, AJAX - This will be a local webpage (no need to host a website for prototyping phase), capable of polling the logged alerts in the cloud database and displaying the results on the browser.

Sub-Components (to be covered in future posts):

• Detecting Smoke with Arduino
• Detecting "fire-like" Heat with Arduino
• Tying the above 2 senses together and detecting fire - compound sensing
• Posting data to the Cloud Platform using ESP8266 with Arduino
• Configuring the IoT Cloud Platform
• Fetching data from the Cloud Platform on a mobile device/PC
• Controlling a Solenoid Valve operated Fire Sprinkler with Arduino
• Sounding the Piezo Buzzer with Arduino

Tying all the above components we can easily build a Smart City - Connected Emergency Response System. I have linked some relevant posts for the above sub-units.

Cheers!
KBRC