ESP32 & ThingSpeak

Going Beyond Basic Charts — Widgets, Dashboards, and Exporting Sensor Data for Industrial Monitoring

1. Introduction

In previous lessons, sensor data from an ESP32 was successfully uploaded to a ThingSpeak channel and displayed using basic field charts. This lesson expands on that foundation by exploring what else ThingSpeak offers beyond simple line-chart views — specifically its dashboard widgets, custom visualization apps, and data export capabilities.

Key takeaway: ThingSpeak is not just a data logger — it is a lightweight IoT dashboard platform that is especially well suited for industrial-style monitoring projects where a full cloud control system may be unnecessary.

2. Why Monitoring Matters

Among the many IoT applications, monitoring stands out as the most common and practical use case for real-world projects. While cloud-based control (turning devices on/off remotely) is technically possible, it is rarely used in real industrial environments due to safety and reliability concerns.

Instead, industries prefer systems that continuously observe parameters like temperature, humidity, pressure, or vibration, and alert operators only when values move outside a safe range. This is exactly the kind of dashboard ThingSpeak helps you build quickly and without extra coding.

ApproachTypical Use CaseIndustrial Preference
Cloud MonitoringView live sensor trends (temp, humidity, etc.)✔ Widely Used
Cloud ControlRemotely switch actuators/relays on/off✘ Rarely Used

3. Dashboard Widgets

On your ThingSpeak channel dashboard, click the “Add Widgets” button to access a library of pre-built visualization components. These widgets sit alongside your regular field charts and can be arranged freely on the dashboard.

3.1 Numeric Display Widget

The simplest widget is the Numeric Display. It shows the most recent value of a chosen field as a large, easy-to-read number — ideal for a control-room screen.

Widget Type: Numeric Display
Field: Field 1 (Temperature)
Widget Name: Room Temperature
Decimal Places: 1
Note: By default, ThingSpeak rounds off decimal values. If you need precise readings (e.g., 24.6°C instead of 25°C), explicitly set the decimal point option while creating the widget.

3.2 Gauge Widget

The Gauge widget displays a value on a semi-circular dial — similar to a speedometer. Previously, developers had to write custom JavaScript gauge code, but ThingSpeak now provides this natively.

4. Configuring a Gauge Widget — Example

Below is a step-by-step example of creating a temperature gauge and a humidity gauge.

4.1 Temperature Gauge

Widget Type: Gauge
Field: Field 1 (Temperature)
Minimum Value: 0
Maximum Value: 60
Warning Range Start: 35
Warning Range End: 60
Units: °C

This configuration ensures the needle covers realistic temperature limits, while the colored warning band (35°C–60°C) visually flags abnormal readings.

4.2 Humidity Gauge

Widget Type: Gauge
Field: Field 2 (Humidity)
Minimum Value: 0
Maximum Value: 100
Units: %

🌡️ Temperature Gauge

Displays live °C reading with a visual warning zone above 35°C.

💧 Humidity Gauge

Displays live relative humidity (%) on a 0–100 scale.

5. Custom Visualizations (Advanced)

For users who need visuals beyond the built-in widgets, ThingSpeak provides an Apps → Visualizations section where fully custom MATLAB-based visualizations can be created.

Navigation: Apps → Visualizations → New

This is considered an advanced topic and is intentionally left for a later stage in the course, since for the vast majority of industrial dashboards, the built-in Numeric Display and Gauge widgets are sufficient.

6. Exporting Channel Data

Beyond visualization, ThingSpeak allows you to export raw sensor data for offline analysis. This is done from the channel’s data view using the export options.

Data View → Export → Select Date Range
Export Format: CSV / XLS

The exported file contains the entry ID, timestamp, and all recorded field values — ready to be opened in Excel, Google Sheets, or any data-analysis tool.

ColumnDescription
created_atTimestamp of the reading
entry_idUnique record number
field1Temperature value
field2Humidity value
Once exported, this data can be used to build custom charts, run statistical analysis, or feed into machine-learning models in Excel or Python.

7. End-to-End Workflow Diagram

The diagram below summarizes the complete data journey from sensor to spreadsheet analytics.

ESP32 + Sensor
ThingSpeak Channel
Widgets / Gauges
CSV / XLS Export
Excel Analytics

8. Summary

In this lesson, we moved beyond basic field charts to explore ThingSpeak’s dashboard widgets — the Numeric Display and the Gauge — both of which require no coding and are perfectly suited for industrial monitoring dashboards. We also learned how to export historical data in CSV/XLS format for deeper analysis in tools like Excel.

Coming up next: We will explore how to perform analytics directly on the exported visualization data.