AWS IoT Core

Connect your Raspberry Pi to AWS IoT Core, over a cellular connection

Easily and securely connect devices to . AWS IoT Core uses MQTT to transmit and receive messages, a lightweight IoT messaging protocol. This tutorial explain how to set up AWS IoT Core and start sending IoT data from a Raspberry Pi connected over cellular.

Prerequisites

Monogoto SIM
Raspberry Pi 3 or 4

Create a Thing in AWS

Search for the IoT Core service

In the left side menu, navigate to Manage > All devices > Things

Click the button Create Things to create your digital Thing.

Name your thing, e.g. mqtt-thing

Select Auto-generate a new certificate

Attach an existing policy, or create a new one by clicking “Create policy”

When creating a new policy, add 4 statements allowing the Thing to Connect, Publish, Receive and Subscribe. Under Policy resource, add an asterisk * to allow all topic names to connect to AWS IoT Core.

Policy effect    Policy action    Policy resource
Allow            iot:Connect      *  
Allow            iot:Publish      *   
Allow            iot:Receive      *  
Allow            iot:Subscribe    *

When using AWS IoT Core in production, restrict the Policy resource to specific topics to increase the security of your application.

Download all keys and CA files

Download and store the Device certificate, Private key file and Amazon Root CA 1 in a directory called certs. Make sure to name the files properly as described in the table below.

Device certificate

device.pem.crt

Private key file

private.pem.key

Amazon Root CA 1

AmazonRootCA1.pem

Connect your device to AWS IoT Core

Access the Raspberry Pi over ssh or by connecting a screen and keyboard

Install the required libraries

Before you install an AWS IoT Device SDK, run these commands in a terminal window on your Linux device to install the required libraries.

sudo apt-get install cmake

sudo apt-get install libssl-dev

Install the AWS IoT Device SDK for Python and download the sample apps to your device.

cd ~
pip3 install awsiotsdk
pip3 install AWSIoTPythonSDK

Add certificates to the Raspberry Pi

Add the Device certificate, Private key file and Amazon Root CA 1 to a folder called certs.

cd ~
mkdir certs

If you downloaded the certificates to a different machine, move the certificates to the RPI using the below command: scp -r ~/certspi@<ip address>:~/certs

Create your python script

Create a new file called `publish.py` containing the below script

# publish.py

# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0

import time as t
import json
import AWSIoTPythonSDK.MQTTLib as AWSIoTPyMQTT

# Define ENDPOINT, CLIENT_ID, PATH_TO_CERTIFICATE, PATH_TO_PRIVATE_KEY, PATH_TO_AMAZON_ROOT_CA_1, MESSAGE, TOPIC, and RANGE
ENDPOINT = "<your AWS endpoint>"
CLIENT_ID = "basicPubSub"
PATH_TO_CERTIFICATE = "/home/pi/certs/device.pem.crt"
PATH_TO_PRIVATE_KEY = "/home/pi/certs/private.pem.key"
PATH_TO_AMAZON_ROOT_CA_1 = "/home/pi/certs/AmazonRootCA1.pem"

MESSAGE = "hello world"
TOPIC = "device/RPI"
RANGE = 3

myAWSIoTMQTTClient = AWSIoTPyMQTT.AWSIoTMQTTClient(CLIENT_ID)
myAWSIoTMQTTClient.configureEndpoint(ENDPOINT, 8883)
myAWSIoTMQTTClient.configureCredentials(PATH_TO_AMAZON_ROOT_CA_1, PATH_TO_PRIVATE_KEY, PATH_TO_CERTIFICATE)

myAWSIoTMQTTClient.connect()
print('Begin Publish')
for i in range (RANGE):
    data = "{} [{}]".format(MESSAGE, i+1)
    message = {"message" : data}
    myAWSIoTMQTTClient.publish(TOPIC, json.dumps(message), 1) 
    print("Published: '" + json.dumps(message) + "' to the topic: " + TOPIC)
    t.sleep(0.1)
print('Publish End')
myAWSIoTMQTTClient.disconnect()

Replace <your AWS endpoint> with your AWS endpoint to the publish.py file (line 11)

In the Settings page you will find the Endpoint, which is unique to your AWS account and looks something like: abcdef1234567-ats.iot.eu-west-1.amazonaws.com.

In the AWS IoT Portal, open the MQTT test client and subscribe to the topic device/RPI

Go back to your Raspberry Pi and run the publish.py script using the command:

python3 publish.py

Expected response

Begin Publish
Published: '{"message": "hello world [1]"}' to the topic: device/data
Published: '{"message": "hello world [2]"}' to the topic: device/data
Published: '{"message": "hello world [3]"}' to the topic: device/data
Publish End

When looking at the MQTT test client in AWS IoT Core, you can see the messages: