IoT-Events

AWS IoT Events Quick Start

AWS IoT Events enables you to monitor inputs from telemetry data sources and trigger actions based on events.

In this lab we will set up automated triggers for actions on HAVC equipment based on a sequence of readings for temperature, CO2, room lighting level, and humidity from rooms in a building.

HAVC will be turned on if 5 consecutive readings indicate that the room is occcupied. A room is considered occupied when the CO2 level is more than 600, or temperature is higher than 70, or light level in the room is greater than 100 lumens.

Hvac will be turned off if a configurable timer set to 60 seconds counts down successfully when the room was not occupied during the count down period. A room is considered unoccupied when the CO2 level is less than 600, and temperature is less than 70, and light level in the room is less 100 lumens.

Step 1 - Create two SNS topics and create subscriptions for email notification

1. Create hvacSetToOff and hvacSetToOn topics
2. Craete the email notification subscription for each topic

Step 2 - Launch a IoT Events detector model

1. On AWS IoT Events Console -> Create detector model -> Click Create new

Step 3 - Create the input format

1. Create a JSON file called sensorData.json with below content

{ "sensorData": { "co2": 23, "light": 750, "temperature": 47, "humidity": 90 }, "hvacData": { "status": "on" } }

2. Upload the input format

• Click on Create Input on detector model screen.
• Input name as sensorInput and Description as Room sensors and hvac status input.
• Upload a JSON file with sensorData.json.
• Scroll down and make sure that the check marks against the input elements from the JSON file are selected.
• Click on Create.

Step 4 - Create the Detector Model

Create the hvacTurnedOn State

1. Create the hvacTurnedOn State: State name hvacTurnedOn
2. Next to OnEnter, click on Add event.

• Event name as initial
• Event condition as true. The event will always be triggered on entry into this state
• Add action to Set Variable, Assign value of variable i to 1. Then click on Save.

Create the hvacTurnedOff State

1. Create the hvacTurnedOff State: State name hvacTurnedOff

2. Next to OnEnter, click on Add event.

• Event name as room unoccupied
• Event condition as timeout("unoccupiedDuration"). The event will be a wait period of 60 seconds for timer to count down to zero, before this condition evaluates to true.
• Add action to Set Variable, Assign value of variable i to 1. Then click on Save.

3. Create an OnInput entry event for the state hvacTurnedOff. If the room remains unoccupied until the timer counts to zero, we will turn the hvac off.

• Next to OnInput, click on Add event.
• Event name as turn off
• Event condition as $input.sensorInput.hvacData.status == "on". The event will set sensorInput.hvacData.status to on.
• Add action to Send SNS message, enter the ARN of the SNS topic hvacSetToOff and use default payload

3. Create another OnInput entry event for the state hvacTurnedOff. It used to check for conditions whether the hvac should be turned on

• Next to OnInput, click on Add event.
• Event name as turn on
• Event condition as ($input.sensorInput.sensorData.co2 >= 600 || $input.sensorInput.sensorData.light >= 100 || $input.sensorInput.sensorData.temperature >= 72 || $input.sensorInput.sensorData.humidity >= 75) && $input.sensorInput.hvacData.status == "off".
• Add action to Set variable. Type variable name as roomOccupied, select Increment as operation.

Create the RoomUnoccupied transition event

1. Create the transition element from hvacTurnedOn to state hvacTurnedOff.

• Event name as RoomUnoccupied

2. Event trigger logic $input.sensorInput.sensorData.co2 < 600 && $input.sensorInput.sensorData.light < 100 && $input.sensorInput.sensorData.temperature < 70 && $input.sensorInput.hvacData.status == "on"

3. Add Event actions: Set timer. For the timer details, select Create as operation. Enter timer name as unoccupiedDuration, Timer duration as 60, Seconds as Unit.

4. Add another Eventaction: Set variable. Type variable name as roomOccupied, select Assign value as operation. For Variable value enter 0.

Create the RoomUnoccupied transition event

1. Create the transition element from hvacTurnedOff to state hvacTurnedOn.

• Event name as roomOccupied

2. Event trigger logic $variable.roomOccupied > 3

3. Add Event actions: Send SNS message. Enter the ARN of the SNS topic hvacSetToOn and use default payload

• Add action to Send SNS message, enter the ARN of the SNS topic hvacSetToOff and use default payload

Connect the Start state to hvacTurnedOn state

1. Connect the Start state to hvacTurnedOn state. Click on Start in the main window, Select hvacTurnedOn from the drop down for Destination state

Edit detector model

1. Set the detector model name from Untitled to hvacModel and description as Turns hvac on or off depending on occupancy.

2. Enter IAM role as workshopIotEventsRole which will be created with the necessary permissions.

3. Then choose Create a detector for each unique key value. For the Detector creation key enter RoomId: By creating a detector for each unique key, you will have separate model instances for each room id.

4. Batch evaluation for evaluation method

Publish the detector model.

1. Click on Publish at the top right of the page.

Step 5 - Turn on logging in IoT Events

1. Click on IoT Event Settings -> Edit
2. Log level: Info and IAM Role IotEventsLogRole

Step 6 - Configure IoT Core to send sensor data to IoT Events

Create a rule in IoT Core that will listen to messages published to our topic and forward them to the detector.

1. On the Create IoT Core Rules hvacEventsRule

• Rule Name: hvacEventsRule
• Description: Forward room sensor inputs to IoT Events.
• Query Statement: SELECT *, topic(2) as RoomId FROM 'hvac/+/status'. The attribute topic(2) in the select statement will append the second element from the topic (specified RoomId) before sending the message to IoT Events.
• Select an action Send a message to an IoT Events Input.
  • Input: sensorInput
  • Role: IoTCoreInvokeIotEventsRole
• Create a rule
  

Step 7 - Test the hvac detector model

1. Publish the following message to topic hvac/R01/status.

{ "sensorData": { "co2": 100, "light": 10, "temperature": 65, "humidity": 60 }, "hvacData": { "status": "on" } }

The detector based on RoomId as R01 should be created

2. After 60 seconds, you will receive message hvac has been turned off

3. Update the inputs to indicate that the room is now occupied. Publish the following message to topic hvac/R01/status. You need publish the similar message 5 times.

{ "sensorData": { "co2": 1000, "light": 800, "temperature": 73, "humidity": 80 }, "hvacData": { "status": "off" } }
{ "sensorData": { "co2": 1100, "light": 800, "temperature": 73, "humidity": 80 }, "hvacData": { "status": "off" } }
{ "sensorData": { "co2": 900, "light": 800, "temperature": 73, "humidity": 80 }, "hvacData": { "status": "off" } }
{ "sensorData": { "co2": 1000, "light": 800, "temperature": 83, "humidity": 80 }, "hvacData": { "status": "off" } }
{ "sensorData": { "co2": 800, "light": 600, "temperature": 71, "humidity": 80 }, "hvacData": { "status": "off" } }

4. The current state of hvac is off and it should be turned on.

Reference

AWS IoT Events Workshop