The voltmeter data measured on the IndusBoard can not only be viewed locally but also transferred to the public internet using API integration or cloud platforms such as ThingSpeak, Blynk, AWS, or Twilio. This makes the system globally connected, so you can monitor voltages from anywhere in the world. For larger applications like battery packs or solar grids, the IndusBoard supports multiple ADC inputs to measure several cells at the same time. If more inputs are required, additional ADC modules or multiple IndusBoards can be combined. To scale up further, the IndusBoard also supports mesh networking — a system where each device (node) can connect and forward data to others, creating a large interconnected network capable of monitoring 100+ batteries in power grids or EV packs.

The IoT system works because the IndusBoard acts as a web server, meaning it hosts an HTML-based dashboard directly from the board. Any Wi-Fi device (phone, laptop, or smart TV) can access this server via a browser. For wireless communication, the IndusBoard supports two Wi-Fi modes: AP (Access Point mode), where the board creates its own hotspot, and STA (Station mode), where it connects to an existing Wi-Fi router. To connect with a router and access the internet, STA mode is used, and the Wi-Fi credentials (SSID and password) must be configured in the code.

To ensure data security, the IndusBoard comes with a built-in AES cryptographic system, which encrypts readings during transfer. Finally, the UI for displaying real-time data is created using standard web technologies — HTML, CSS, and JavaScript — so users can see live updates of voltage readings in a clean and interactive interface.

Key IoT Concepts for Voltmeter System

What is a Web Server?

A web server is a combination of software and hardware that receives, processes, and responds to client requests over a network. In IoT, the IndusBoard Coin itself can act as a web server. It hosts a simple HTML/CSS/JS webpage inside its memory and delivers it to any device connected via Wi-Fi. For example, when you connect your phone to the IndusBoard, opening the IP address (like 192.168.4.1) loads the live voltmeter dashboard.

Communication Protocols (TCP, UDP, HTTP, MQTT)

IoT devices use standard communication protocols to transfer data:

• TCP (Transmission Control Protocol): Reliable, ensures data is delivered correctly. Used when accuracy is critical (e.g., voltmeter readings).
  
• UDP (User Datagram Protocol): Faster but less reliable. Suitable for real-time streaming (e.g., sensor updates, video).
  
• HTTP/HTTPS: Application-level protocol built on TCP, used for serving web pages and dashboards. HTTPS adds security.
  
• MQTT (Message Queuing Telemetry Transport): Lightweight IoT protocol for sending small sensor messages to cloud platforms (publish/subscribe model).
  

Each protocol has a role: TCP/HTTP for accuracy and dashboards, UDP for speed, and MQTT for cloud IoT integration.

AP Mode and STA Mode

Wi-Fi on IndusBoard can work in two main modes:

• AP (Access Point Mode): The board acts like a Wi-Fi hotspot. Other devices (phones, laptops, smart TVs) connect directly to it. Useful for local testing where no router is available.
  
• STA (Station Mode): The board connects to an existing Wi-Fi router, just like your laptop or phone. This allows the board to send data to the internet/cloud and be accessed globally.
  

Example: Use AP mode for direct board-to-phone connection at a lab bench; use STA mode for remote monitoring via internet.

Dashboards

An IoT Dashboard is the user interface where real-time data is visualized. The IndusBoard hosts its own dashboard using HTML, CSS, and JavaScript, but you can also integrate with cloud dashboards (e.g., ThingSpeak, Blynk). Dashboards typically show values, graphs, and controls to interact with IoT devices.

Webhooks

A webhook is a way for one system to automatically send data to another system in real time when an event happens. For example, when voltage crosses a threshold, the IndusBoard can trigger a webhook to send data to a server or messaging app (like Twilio for SMS alerts). This eliminates manual checking and adds automation.

ThingSpeak

ThingSpeak is a free IoT cloud platform by MathWorks. It allows devices to send sensor data (via HTTP/MQTT) and provides ready-made graphs and dashboards. With ThingSpeak, you can monitor voltmeter data globally, set alerts, or even run analytics in MATLAB.

Twilio

Twilio is a cloud communication platform. It connects IoT systems to mobile networks, allowing SMS, voice calls, or WhatsApp alerts. For example, if your solar battery voltage drops too low, the IndusBoard can send data via webhook → Twilio → SMS alert to your phone.