Smart Water - Level Monitoring System

Executive Summary
The Water Rat is an advanced IoT-based water monitoring solution developed by Dotcom IoT for agricultural applications based on Client requirement.
Designed for remote and harsh farm environments, the device enables real-time detection of water availability in tanks, troughs, and wells. Using intelligent tilt-based sensing and LPWAN cellular communication, the system ensures continuous monitoring with minimal human intervention.
The solution significantly improves operational efficiency, reduces water shortages, and enhances livestock management through timely alerts and actionable data insights.

Client Overview

The client is an Australia-based AgriTech company focused on delivering smart digital solutions for modern farming and livestock management.

Their offerings span across:

• Livestock monitoring and cattle tracking
• Water management solutions
• Crop health monitoring and farm analytics

With a strong emphasis on improving farm efficiency and sustainability, the client leverages technology to provide real-time visibility and data-driven insights to farmers operating in remote and large-scale agricultural environments.

As part of their water management solution portfolio, they required a robust and reliable IoT device to monitor water availability in tanks and troughs-ensuring uninterrupted supply for livestock and optimizing farm operations.

The Challenge

• Environmental & Hardware Challenges: Exposure to water, dust, and humidity leading to corrosion and device failure, Reduced device lifespan due to harsh outdoor conditions, Difficulty in maintaining a fully sealed and rugged enclosure
• Connectivity & Deployment Issues: Traditional physical SIM-based design affecting waterproofing, Inconsistent connectivity in remote farm locations, Lack of flexibility in selecting optimal cellular networks
• Power & Efficiency Constraints: High power consumption impacting battery life, No optimized mechanism for low-power operation,
  
• Inefficient data transmission methods
• Monitoring & Intelligence Gaps: No reliable method to detect water availability in real-time, Dependence on manual inspection of tanks and troughs, Lack of event-based alert system
  
• Firmware & Scalability Limitations: Absence of secure OTA (Over-the-Air) updates, Limited scalability for future enhancements, Difficulty in configuring devices remotely

Development Challenge

1. Event Detection Accuracy > Ensuring reliable detection of real-world conditions using tilt-based logic required careful calibration. Avoiding false triggers due to external disturbances and maintaining consistent performance across different deployment scenarios was a significant challenge.
2. State Machine & System > Managing transitions between multiple operating modes such as transport, cellular, and BLE introduced complexity in system behavior. Implementing reliable magnet-based control logic for time-based actions under low-power conditions was also challenging. > Additionally, designing a stable hierarchical state machine (HSM) to handle nested states and edge cases required careful structuring.
3. OTA Update Reliability > Implementing firmware updates over the air introduced challenges related to network dependency and reliability. Ensuring that firmware updates could be performed over low-bandwidth cellular networks without causing device instability or failure was a critical concern during development.
4. Power Management > Designing a low-power system was challenging, as sensors and communication modules needed to be activated selectively based on operational requirements. Ensuring efficient control over these components while maintaining minimal power consumption was critical for overall system performance.

Hardware Architecture

• The hardware architecture of the system is built around a central Cellular SoC-based design, enabling efficient coordination between sensing, processing, and communication functionalities. The objective was to create a system that can reliably operate in remote agricultural environments while maintaining low power consumption and stable performance.
• The Cellular SoC acts as the core of the device, continuously interacting with multiple connected modules to acquire data, process it locally, and initiate communication when required. By performing initial processing at the device level, the system reduces unnecessary data transmission and optimizes overall efficiency.
• The architecture is designed in a way that all key components-sensors, communication modules, and control interfaces-work together seamlessly, ensuring accurate data capture and timely response to environmental changes.

• The device is powered by a battery system, with a dedicated power regulation stage to ensure stable voltage across all components.
• The Cellular SoC communicates with sensors and peripherals using standard interfaces such as I2C, UART, GPIO, PWM, and ADC.
• Sensor data is periodically sampled and also monitored for event-based triggers such as tilt or temperature changes.
• Based on predefined conditions, the Cellular SoC initiates communication with external networks or activates local indicators.

• Cellular SoC: Serves as the central processing unit, managing sensor inputs, executing logic, and controlling communication flow.
• Temperature Sensor: Monitors ambient conditions to ensure reliable operation and provide additional environmental insights.
• BLE Interface: Enables short-range communication for configuration, commissioning, and diagnostics.
• e-SIM Integration: Facilitates seamless and secure network connectivity without the need for physical SIM handling.
• Buzzer: Provides audible feedback during device interaction and mode transitions.
• Tilt Detection Sensor (Accelerometer): Provides continuous orientation data, enabling the system to detect water presence based on angle variation.
• Cellular Communication Module: Responsible for transmitting device data over long-range networks, ensuring connectivity in remote areas.
• GNSS Capability: Allows the device to capture location data for deployment validation and tracking purposes.
• Reed Switch Mechanism: Acts as a magnetic trigger for switching between different operating modes.
• Battery Monitoring Circuit: Continuously tracks battery status and feeds data to the Cellular SoC for reporting and alerts.

• Intelligent control of sensor sampling and processing
• Event-based wake-up mechanisms
• Controlled communication intervals
• Efficient use of sleep modes during inactivity

• Device supports multiple operating modes for different use cases
• Mode switching is triggered using a magnetic input mechanism

• 2 Beeps → Transport Mode
• 4 Beeps → Cellular Mode
• 6 Beeps → BLE Mode

Communication & Connectivity

• The system is designed with a robust and efficient communication architecture to ensure reliable data transmission from remote field locations to the cloud. Considering the challenges of agricultural environments, the communication layer is optimized for long-range coverage, low power consumption, and minimal data usage.
• The device leverages low-power cellular technologies to maintain connectivity even in areas with limited network infrastructure. It intelligently manages when and how data is transmitted, ensuring that critical information is delivered without unnecessary power consumption.

• NB-IoT (Narrowband IoT)
• LTE Cat-M (LTE-M)

• Long-range communication in remote areas
• Better indoor and underground penetration
• Lower power consumption compared to traditional cellular systems

Communication Flow

• The system follows a well-defined communication flow to ensure reliable and efficient data delivery.
• At the device level, relevant data is collected and transmitted over the cellular network. This data is received by the CoAP server, where it is processed and forwarded to the application layer for further use. Based on the received information, the system can trigger alerts or update the user interface.
• End users can access this data through web or mobile applications, allowing them to monitor water availability, device status, and other key parameters in real time.

Protocol & Configuration
The communication is designed to be lightweight, efficient, and adaptable to different deployment scenarios.

• The system uses the CoAP (Constrained Application Protocol), which is specifically optimized for low-power IoT devices. It enables efficient data exchange with minimal bandwidth usage, making it suitable for remote and network-constrained environments.
• Communication is structured in a way that only relevant and necessary data is transmitted, reducing network load and improving overall efficiency.
• The device supports BLE-based configuration, allowing users to connect locally and modify parameters such as thresholds, reporting intervals, and operational settings in real time.
• In addition to local configuration, the system also supports remote parameter updates, ensuring flexibility and ease of management across deployed devices.

This combination of lightweight protocol and flexible configuration ensures smooth operation, faster communication, and better control over the system.
Communication Efficiency
To maintain long battery life and efficient operation:

• Data transmission is primarily event-driven, reducing unnecessary communication
• Periodic heartbeat messages ensure device health monitoring
• Communication intervals are optimized to balance performance and power consumption

System Working Principle

• The system is designed to detect water availability using a tilt-based sensing mechanism, providing a simple and reliable alternative to traditional water level sensors.
• The device is installed in such a way that its orientation changes based on the presence or absence of water. By continuously monitoring this orientation, the system can accurately determine water availability.

Working Logic

• When water is present, the device remains in its normal position
• As the water level drops, the device orientation changes
• The tilt sensing mechanism detects this change
• If the tilt exceeds a predefined threshold, it is identified as a water-level event
• Threshold values (tilt / temperature) are configurable via application
• Device compares real-time sensor data with configured thresholds
• Any deviation triggers an event

Event Detection & Reporting
Once a threshold condition is met:

• The device internally processes the event
• Relevant data is transmitted to the CoAP server
• The application layer updates the status and triggers alerts to the user

Alert:

• Tilt-based water alert
• Temperature-based alerts (including extreme/ice conditions)
• Battery level drops below threshold

Monitoring Approach

• Continuous monitoring of device orientation
• Event-based alert generation
• Periodic heartbeat updates for device health and status

“Transforming simple sensing into reliable water intelligence - built to perform in real-world agricultural conditions where reliability matters the most.”