End-to-end IoT sensor data live visualization and a Cooler / Heater control using AWS IoT Cloud.

This project is to capture temperature and humidity data from a BTREE IoT SENSOR and send it to a DynamoDB table in AWS cloud server and simultaneously display a live chart on a website url using AWS IoTcore, AWS DynamoDB, AWS S3 website, NodeJS and ChartJS.

This project also demonstrates how we can control 2 relays that controls a cooler and a heater automatically and manually  based on the sensor temperature and humidity values.

When temperature increases from a preset value the cooler will be ON automatically and when the humidity increases from a preset value, then the heater will be ON automatically.

NodeMCU-DHT22>AWS IoT->DynamoDB->NodeJS->ChartJS->AWS S3-website.

AWS Cognito Login page:    

Please check this url for a live view of sensors:

 https://btree-iot-dashboard.s3-website-us-west-2.amazonaws.c…

Please check this url for a live view of cooler/heater control:
 https://btree-iot-dashboard.s3-website-us-west-2.amazonaws.c…

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STEPS:

Create a Thing in AWS IoT CORE:

1. Create a **Thing** first
2. Single Thing

– Create a AWS IoT Thing

3. Thing Name

– Provide a **Name** to the Thing

4. Create Certificates

– Click on **Create Certificate**

5. Download Certificates

Download the following

– Contents for **client_cert[]** from **XXXXXXXXXX.cert.pem**

– Contents for **privkey[]** from **XXXXXXXXXX.private.key**

– Contents for **cacert[]** from **[Root CA ]

6. Download the Root CA Certificate

– Download the **RSA 2048 bit key**

7. Attach the Policy created

CREATE A PLOICY: – SECURE – POLICIES – CREATE

8. Interact with AWs IoT Core – Find the ARN of the thing

A thing Amazon Resource Name uniquely identifies this thing.

Eg: arn:aws:iot:us-west-2:xxxxxxxxxx:thing/btree-iot-sensor

MQTT: MQ Telemetry Transport

It is a publish/subscribe, extremely simple and lightweight messaging protocol, designed for constrained devices and low-bandwidth, high-latency or unreliable networks.

9. CREATE A DynamoDB rule:

AWS-IOT -> ACT -> RULES -> CREATE

mqtt topic name:  my/outTopic

Rule: select *, timestamp() AS ts from ‘my/outTopic’

Hardware: NodeMCU ESP8266, DHT22 temperature sensor

Palatform: AWS IoT Core

Programming: Arduino IDE

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// CODE FOR DHT22 ///////////////////////////////

// GPIO-14  DTH22   – D5 – TEMEPERATURE SENSOR

uint8_t DHTPin = 14; //NODE MCU D5             

// Initialize DHT sensor.

DHT dht(DHTPin, DHTTYPE);  

void reconnect() {

// Loop until we’re reconnected

while (!client.connected()) {

Serial.print(“Attempting MQTT connection…”);

// Attempt to connect

if (client.connect(“BTREEHOMERELAYS”)) {

Serial.println(“connected”);  // Once connected, publish an announcement…

client.publish(“my/outTopic”, “hello world”);  // … and resubscribe

client.subscribe(“my/inTopic”);

} else {

Serial.print(“failed, rc=”);

Serial.print(client.state());

Serial.println(” try again in 5 seconds”);

char buf[256];

espClient.getLastSSLError(buf,256);

Serial.print(“WiFiClientSecure SSL error: “);

Serial.println(buf);

// Wait 5 seconds before retrying

delay(5000);

}

}

}

// Load certificate file

File cert = SPIFFS.open(“/cert.der”, “r”);

if (!cert) {

Serial.println(“Failed to open cert file”);

}

else

Serial.println(“Success to open cert file”);

delay(1000);

if (espClient.loadCertificate(cert))

Serial.println(“cert loaded”);

else

Serial.println(“cert not loaded”);

// Load private key file

File private_key = SPIFFS.open(“/private.der”, “r”);

if (!private_key) {

Serial.println(“Failed to open private cert file”);

}

else

Serial.println(“Success to open private cert file”);

delay(1000);

if (espClient.loadPrivateKey(private_key))

Serial.println(“private key loaded”);

else

Serial.println(“private key not loaded”);

// Load CA file

File ca = SPIFFS.open(“/ca.der”, “r”);

if (!ca) {

Serial.println(“Failed to open ca “);

}

else

Serial.println(“Success to open ca”);

delay(1000);

if(espClient.loadCACert(ca))

Serial.println(“ca loaded”);

else

Serial.println(“ca failed”);

}

Message protocol: MQTT

Prerequisite

1. Amazon AWS cloud service account

Steps:

1. create a thing in AWS IoT core
2. generate certificates and download
3. create  policy
4. convert certificate files to  .der format

Converting AWS IoT Core credential(Certificate, Private Key, Root CA) from .pem to .der format

There are two main methods for encoding certificate data.

• DER = Binary encoding for certificate data
• PEM = The base64 encoding of the DER-encoded certificate, with a header and footer lines added.

Installing OpenSSL

OpenSSL open-source implementation of SSL and TLS protocols and that can be used to convert the certificate files into the most popular X.509 v3 based formats.

We will convert the .pem files to .DER.

Linux:  install OpenSSL with the following YUM console command:

yum is the primary tool for getting, installing, deleting, querying, and managing Red Hat Enterprise Linux RPM software packages from official Red Hat software repositories, as well as other third-party repositories

$ yum install openssl

> openssl x509 -in 1234561-certificate.pem.crt.key -out cert.der -outform DER  > openssl rsa -in 1234561-private.pem.key -out private.der -outform DER > openssl x509 -in G2-RootCA1.pem.txt -out ca.der -outform DER

5. Downloaded the converted certificate files into the NodeMCU ESP8266 SPIFFS file system.

6. Copy the AWS_endpoint which is the address of the MQTT broker for your AWS account in a specific region.
7. Place it in aurdino code:
   const char* AWS_endpoint = “xxxxxxxxxxxxxx-ats.iot.us-west-2.amazonaws.com”; //MQTT broker ip

Create DynamoDB – Tablename: btree_iot_table
schema:

id string  ( for mqtt topic )
timestamp number ( time & day timestamp value )

Setting up Amazon DynamoDB

1. Setting up Amazon DynamoDB & Creating a rule to fetch data from the MQTT topic then pass to DynamoDB.
2. Implementation of code to post mac_Id, random_number, randon_string from ESP8266 to AWS
3. Demo: Data Storing into the Amazon DynamoDB

Before diving into this tutorial make sure you have comple

Before diving into this tutorial make sure you have completed the following two steps because this tutorial is a continuation of the following to tutorials.

1. Creating a Thing in AWS
2. Connecting NodeMCU (ESP8266) with AWS IoT Core.

1. Creating an Amazon DynamoDB rule and Setting up a DynamoDB data table.

What is AWS Rule? what it does???

An AWS IoT rule consists of an SQL SELECT statement, a topic filter, and a rule action. Devices send information to AWS IoT by publishing messages to MQTT topics. The SQL SELECT statement allows you to extract data from an incoming MQTT message. The topic filter of an AWS IoT rule specifies one or more MQTT topics. The rule is triggered when an MQTT message that matches the topic filter is received on a topic. Rule actions allow you to take the information extracted from an MQTT message and send it to another AWS service. Rule actions are defined for AWS services like Amazon DynamoDB, AWS Lambda, Amazon SNS, and Amazon S3. By using a Lambda rule, you can call other AWS or third-party web services. For a complete list of rule actions, see AWS IoT Rule Actions.

Creating an Amazon DynamoDB rule.

DynamoDB rules allow you to take information from an incoming MQTT message and write it to a DynamoDB table.

table Name: btree-iot-sensor

coloums: id, string  – add sortkey – yes

timestamp, number

create

mqtt topic name:  my/outTopic

Rule: select *, timestamp() AS ts from ‘my/outTopic’

publish topic to test

eg:

{

“mac_Id”: “12345”,”temperature”: “32.50”,  “humidity” : “83.50”

}