Node-RED is an open source visual flow-based programming tool used for wiring not only Internet of Things (IoT) components, but also integrating an ensemble of service APIs, including ones provided by IBM Cloud.
This repository provides an example of a Node-RED application that is supposed to grab sensor data from DHT11 sensor connected to a Raspberry Pi and visualize this data. Based on the sensor data gathered, an alert signal could be sent to notify the user that the sensor data (ie. temperature and/or humidity) are out side a defined range. This is just a simple exercise to show how to use Watson IoT Platform services to publish events from and to send commands to the Raspberry Pi.
The application explored in this repository can be deployed into IBM Cloud via the simple steps explained below.
The Raspberry Pi 3 communicates with the DHT11 sensor to collect temperature and humidity data that is to be sent to IBM Cloud via MQTT. This process is simplified through the usage of the Internet of Things Platform service available on IBM Cloud. If values of the temperature and humidity are not within a particular range, a signal is sent through Watson IoT Platform service to alert the user through lighting up a LED. Both the sensor data are stored in a Cloudant NoSQL database to allow the convenient access to them at any point in time.
The connecting of the described components is made possible and simple through the deploying a Node-RED Node.js application instance.
An architecture overview of the system can be found below.
For the connection between the Raspberry Pi and the other components, check the schematic below.
You will find that there is a file called rpi_iotf.py, which you will need to copy onto the Raspberry Pi.
You also need to download a dht11.py file and make sure both dht11.py and rpi_iotf.py files are in the same directory. To do so, input below command to download it:
sudo wget http://osoyoo.com/driver/dht11.pyThe file is then imported in dht11.py, which will allow you get it humidity and temperature sensor data.
To install the latest version of the library, input below command:
pip install ibmiotfThe file is then imported in dht11.py, which allow us to publish events to and send commands from Watson IoT Platform service.
An IBM Cloud account - A lite account, which is a free of charge account that doesn’t expire, can be created through going to IBM Cloud.
There are three components to configure:
- Node-RED application
- Internet of Things Platform service
- Cloudant NoSQL database
To simplify connecting these three, a boilerplate called Internet of Things Platform Starter is used. It can be found by going to Catalog followed by selecting Boilerplates, which can be seen on the menu available on the left-hand side. The user is then required a unique name for the application being created, which is also used as the hostname. If the user is using a lite account, the region is set to that chosen while applying for the account. After clicking on create, an instance of the Node-RED application is created to which both the Internet of Things Platform service and Cloudant NoSQL database are bound. It will take some time for the application status to change to awake, indicating that it is running.
From the hamburger menu at the top left of the page, the user can access the dashboard, which will allow the user to see all the applications and services that have been created. Click on the name of the application to go to a window that provides more details about the application. If you click on Connection on the menu seen on the left hand-side, you will notice that there are two connections: -cloudantNoSQLDB and -iotf-service.
If we click on -iotf-service, it will take us to the page with the details about the Internet of Things Platform service. Go to Manage and then click on Launch. This will take us to the page where we can configure devices we can connect to among other things. At the top right of the page, we see an ID, this is the organization ID and it is one of the things needed to configure the connection between a device and the Internet of Things Platform service.
Here, we are required to configure a device type to which we will be adding a device. Go to Devices from the menu on the left, and from the newly opened page, click on Device Types followed by Add Device Type. Here you will provide the name and metadata describing the device type to create the device type. Then, click Register Devices to add a device to that particular device type. Enter a Device ID, metadata describing the device and select an option to define the authentication token. After you are done, you will be directed to a page summarizing the device’s credentials. Copy the credentials into a notepad for later use (It will be used by both the Raspberry Pi to send data and the Node-RED application to get the data).
In order to communicate with Internet of Things Platform service, you will notice that, in the file we added to the Raspberry Pi, we have included the code snippets below to the appropriate locations, where you will change the organization, deviceType, deviceId, and authToken to that corresponding to the credentials we copied earlier.
import ibmiotf.device
oorganization = "" #add organisation from the IoT platform service
deviceType = "" #add device type from the IoT platform service
deviceId = "" #add device ID from the IoT platform service
authMethod = "token"
authToken = "" #add authentication token from the IoT platform service
# Initialize the device client.
deviceOptions = {"org": organization, "type": deviceType, "id": deviceId, "auth-method": authMethod, "auth-token": authToken}
client = ibmiotf.device.Client(deviceOptions)
print("init successful")
def myOnPublishCallback():
print("Confirmed event received by IoTF")
# Connect and send a datapoint
def send(data):
success = client.publishEvent("data", "json", data, qos=0, on_publish=myOnPublishCallback)
if not success:
print("Not connected to IoTF")
# get a command from Watson IoT Platform
def myCommandCallback(cmd):
print("Command received: %s\n" % cmd.data)
client.connect()
send({"temp":temp, "hum": hum})
client.commandCallback = myCommandCallback
client.disconnect()If we click on -cloudantNoSQLDB, it will take us to the page with the details about the Cloudant NoSQL DB service. Go to Manage and then click on Launch. This will launch an interface through which we can interact with the Cloudant NoSQL DB. Click on the Databases from the menu available on the left. By default, a database named nodered can be found, which we are not going to touch. Now, click on Create Database at the top of the page to create a new Database and give it a name (here, we called it iotdb) and click create. Here, we will be saving any data we will be receiving. Whenever we want to store something, we store that data in a document in a NoSQL database.
Go back to the dashboard and click on the application you created earlier. In order to access the Node-RED editor used to build the application, click on Visit App URL. Follow the directions to access the Node-RED editor (you are encouraged to secure your Node-RED editor to ensure that only authorized users can access it). Click on Go to your Node-RED flow editor.
A new Node-RED flow appears containing nodes representing a sample application. Select all the nodes and delete them as we will be importing our own flow. There are nodes that we will be working with, whose module we need to install. This can be achieved by going to the hamburger menu again and clicking on Manage palette. In the Install tab, we will search for node-red-dashboard module and install it. If look at the node type menu on the left hand-side, we will notice that a number of nodes have been added under the dashboard node type.
In this repository, go to the file called Node-REDflow_Full.json and copy its content. In the Node-RED editor, go to the hamburger menu at the top right of the page after which select Import Clipboard. Paste the content of the JSON file and click on Import.
The ibmiot in node found in the flow allows us to consume any data received by the IoT Platform service. By double-clicking on the node, we can change its properties and set the Authentication to Bluemix Service, Device Type and Device id to the device type and device id that we defined in the IoT Platform service. Keep Input Type as Device Event. We will connect it to a debug node, which can be found under output node type. Before we continue, we will check if our application can receive any data from the Raspberry PI, which should show as a JSON object under the debug tab on the right.
The cloudant out node found in the flow is used to store the temperature and humidity sensor data. Double-clicking on the node and change Service to the name of your Cloudant NoSQL DB that was created earlier. Moreover, input the name of the database (in our case, it is iotdb) in the field corresponding to Database and keep the Operation as insert.
The ibmiot out node found in the flow allows us to send an commands from the IoT Platform service. By double-clicking on the node, we can change its properties and set the Authentication to Bluemix Service, Device Type and Device id to the device type and device id that we defined in the IoT Platform service. Keep Output Type as Device Command. Insert cmd as the Command Type and {"test":0} as the Data, which is overwritten by the payload sent by the function node called Alert.
Make sure to hit Deploy to see the changes. Moreover, don't forget to run the python script placed on the Raspberry Pi.
Now that all the operational nodes are done, it is time to create and customize the dashboard, which provides the User Interface (UI) part of the application. On the right hand-side of the page, click on the dashboard tab. We will notice that there are 3 tabs, each used to change the look and feel of the UI (layout, Theme & Site).
The node used as part of the dashboard in the flow is the chart node. This is the node that will allow us to visualize the change in temperature and humidity over time.
The dashboard UI should look something similar to the image below, which can be reached by going to the dashboard tab and clicking on the window expand looking icon.
Finally, deploy and you are done!!