Low-Code Implementation of Status Monitoring with Raspberry Pi and Node-RED

HongKe Technology

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Node-RED is a programming development tool used to connect hardware devices, APIs, and online services in novel and interesting ways. During the development process of the HongKe Industrial Raspberry Pi, Node-RED can be utilized to implement industrial IoT applications, reducing development difficulty. In previous articles, we briefly introduced popular science knowledge about Node-RED for the HongKe Industrial Raspberry Pi. Next, the HongKe Industrial IoT team will continue to explain how to build an IoT platform step by step. This article presents the first application explanation—implementing status monitoring for the industrial Raspberry Pi.

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1. Nodes

All nodes can be installed in the node manager

(1) node-red-dashboard

This is an essential node for building visual interfaces, containing 16 controls, which are necessary for building visual interfaces. Using the controls within the node can quickly create monitoring interfaces.

(2) node-red-node-email

Email sending and receiving node, used for notifying the responsible person via email in emergencies.

(3) node-red-contrib-simpletime

Time node, used to display system time.

2. Controls

The nodes contain many controls; this article only introduces the controls used to build the status monitoring interface. If you are interested in other controls, you can click the corresponding control to view the introduction:

(1) Switch & Button Controls

The switch control and button control are both buttons and can be used as status monitoring switches. The difference is that the button control triggers once every time it is pressed, equivalent to a momentary switch in circuit applications, which will reset automatically; the switch control maintains its state every time it is pressed, equivalent to a latching switch in circuit applications.

(2) Text Control

This control is used to display system time.

(3) Gauge Control

The gauge control’s main function is to serve as a dashboard to display data. In this application, this control is used to display data and act as an indicator light.

(4) Chart Control

This control is a chart control, which can be used as a line chart or bar chart to display data changes or data comparisons. In this application, this control is used to display data change trends.

(5) Notification Control

The notification control can operate reminders. In this application, this control is used for interface alarms.

(6) Email Control

The email control’s function is to send emails. In this application, this control is used for email reminders to relevant personnel.

(7) Simpletime Control

The simpletime control’s function is to obtain time. In this application, this control is used to obtain the raw time, which is then integrated through functions to form a complete system time.

(8) Function Control

The function control is used to write functions to process data and output the desired values. In this application, data processing is mainly achieved through simple statements.

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1. Processor Temperature Monitoring

(1) Switch Settings

Drop down “Group” to select and add a new group;

(2) Dashboard Settings

Modify according to the following image, where:

Group: must be selected the same as the switch control to ensure that this control and the switch control are on the same interface;

Type: this control provides four display methods, which can be selected according to needs;

Label: set the name displayed by this control

Units: set the units;

Range: set the maximum and minimum values for this control;

Note: Units and Range will change with the selection of Type.

(3) Change Curve Settings

Group: must be selected the same as the switch control to ensure that this control and the switch control are on the same interface;

Label: set the name displayed by this control;

Type: this control provides six display methods, which can be selected according to needs;

X-axis: set the range displayed on the horizontal axis;

Legend: set the display method of the curve;

Note: X-axis and Legend will change with the selection of Type.

(4) Effect

2. Indicator Light Monitoring (Simulation)

(1) Status Simulation Settings

Drop down “Group” to select and add a new group;

Add three button controls, with Label and Payload set according to the following rules:

• Normal Operation: 5

• Abnormal Operation: 10

• Standby Status: 15

(2) Indicator Light Settings

Group: must be selected the same as the switch control to ensure that this control and the switch control are on the same interface;

Type: this control provides four display methods, which can be selected according to needs;

Label: set the name displayed by this control;

Range: set the gauge range;

Sectors: set different colors for different ranges of data display, where “Normal Operation” corresponds to “Green”, “Abnormal Operation” corresponds to “Red”, and “Standby Status” corresponds to “Orange”.

(3) Popup Alarm Settings

• Notification Control Settings

Layout: set the popup mode, which can be selected according to needs;

Default action label: set the popup button;

Topic: set the popup topic;

Name: set the control name;

• Function Control Settings

  Add the following function:

(4) Email Alarm Settings (2 Methods)

• Email Control Settings

Need to enable IMAP for the email (receiving/sending) and obtain the authorization code:

To: set the email address to receive emails

Userid: set the email address to send emails

Password: fill in the authorization code corresponding to the email address used to send emails

Name: set the control name

• Conditional Judgment Settings (2 Methods)

  Change Control

Function Control

(5) Effect

3. System Time Settings

(1) Simpletime Control Settings

(2) Function Control Settings

(3) Effect

4. Final Effect

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The main functions achieved by this platform are as follows:

(1) Display system time;

(2) Real-time display of the temperature value of the HongKe Industrial Raspberry Pi processor and temperature changes;

(3) The three buttons “Standby Status”, “Normal Operation”, and “Abnormal Operation” simulate the three states of the HongKe Industrial Raspberry Pi during operation. Pressing the “Normal Operation” button will display green on the dashboard, and the HongKe Industrial Raspberry Pi A1 and A2 indicator lights will show green; pressing the “Standby Status” button will display green on the dashboard, and the HongKe Industrial Raspberry Pi A1 and A2 indicator lights will show orange; pressing the “Abnormal Operation” button will display red on the dashboard, and the HongKe Industrial Raspberry Pi A1 and A2 indicator lights will show red;

(4) Message notifications; pressing the “Abnormal Operation” button will trigger a popup reminder for the operator and send an email to notify relevant personnel.

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Throughout the construction process of the status monitoring platform, apart from applying a small amount of simple code in the function control to achieve data parsing and conversion, the rest was accomplished through simple configuration and wiring of controls to form a data flow to meet the requirements.

Node-RED includes thousands of nodes, each containing controls, and different combinations of controls can produce different effects. Next, HongKe will continue to share in-depth applications of the HongKe Industrial Raspberry Pi combined with Node-RED, stay tuned.

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