Embedded Systems and IoT - ISI LT - a.y. 2025/2026

Assignment #03 - Smart Tank Monitoring System

v1.0.0-20251112

We want to realise an IoT system monitoring the rainwater level of a tank. The system is composed of 4 subsystems:

Description

Components

The system is composed by four subsystems:

• Tank Monitoring subsystem (TMS) - based on ESP
  • embedded system to monitor the rainwater level in the tank
  • It interacts with the Control Room subsystem (CUS) via MQTT
• Control Unit subsystem (CUS) - Back-end, running on a PC
  • main subsystem, governing and coordinating the whole system
  • It interacts via MQTT with the Tank Monitoring Subsystem (TMS)
  • It interacts through the serial line with the Water Channels Subsystem (WCS)
  • It interacts via HTTP with the Dashboard Subsystem (DBS)
• Water Channel Subsystem (WCS) - based on Arduino
  • Embedded system controlling the water channel connecting the tank with the water channel network.
  • It interacts via serial line with the Control Unit Subsystem (CUS).
  • It provides a panel for human operators to interact in place.
• Dashboard subsystem (DBS) - Frontend/web app, running on the PC or any device
  • Front-end for remote operators to visualise data and interact with the system.
  • it interacts via HTTP with the Control Unit Subsystem.

Hardware components

• TMS
  • SoC ESP32 board (or ESP8266) including:
  • 1 sonar
  • 1 green led
  • 1 red led
• WCS
  • Microcontroller Arduino UNO board including:
  • 1 servo motor
  • 1 potentiometer
  • 1 tactile button
  • 1 LCD display

Description of the behaviour

The system is meant to monitor the rainwater level inside the tank, and - depending on values - controlling the opening of a water channel connecting the tank to a network of water channers. The overall system can be in two different modes: AUTOMATIC or MANUAL. In AUTOMATIC mode, the system automatically controls the opening of the water channel, depending on the current rainwater level in the tank. In MANUAL mode, the opening is controlled manually by an operator. The starting mode when booting is AUTOMATIC.

Details

• The TMS is responsible for continuously monitoring the level of the rainwater level, by means of proper sensors (e.g. a sonar).

  • The rainwater level are sampled at frequency F and sent to the CUS subsystem.
  • When the system is working correctly (network ok, sending data ok) the green led is on and the red is off; otherwise – in the case of network problems – the red led should be on and the green led off.

• The WCS subsystem is responsible for controlling a valve (with a motor) opening/closing a water channel draining water from the tank to the water channel network.

  • The opening range is in percentage: from 0% = channel closed (motor position 0 degree), up to 100% = channel full open (motor position 90° degree).
  • The water channel opening level depends on the state of the system, established by the CUS subsystem (see later).
  • The WCS includes a button to enable the MANUAL mode, in particular:
    • When the button is pressed, the system enters in MANUAL mode, so that the water channel opening level can be manually controlled by operators using a potentiometer.
    • To exit from the MANUAL model, the button must be pressed again.
  • The WCS subsystem is equipped also with an LCD display reporting:
    • the current valve opening level of the water channel.
    • the current mode (AUTOMATIC or MANUAL), or UNCONNECTED (see later).

• The CUS subsystem is in charge of the policy governing the behaviour of the system. In particular:

  • Rainwater level monitoring
    • When the rainwater level exceeds the level L₁ (but below L₂, with L₁ < L₂) for more than T₁ time, the water channel is opened at 50% until the rainwater level is below L₁.
    • If the the rainwater level exceeds the level L₂, the water channel is immediately opened at 100%, until the value is below L₂.

  If the CUS is not receiving data for more than T₂ time units from the TMS (because of network problems), then the system enters into an UNCONNECTED state, which is restored to a normal state only if/when the network problems are solved.

• The DBS subsystem is a dashboard for visualising the state of the Tank Monitoring system, including:

  • A graph of the rainwater level, considering the last N measurements.
  • The current value of the valve opening percentage.
  • The state of the system: MANUAL, AUTOMATIC, UNCONNECTED or NOT AVAILABLE.
    • the state is labelled as NOT AVAILABLE when the CUS is not reachable, for any reason.

  Besides, it includes:

  • a GUI button to switch the modality (MANUAL, AUTOMATIC).
  • a GUI widget to control the opening level of the valve in the WCS (when in MANUAL mode).

The assignment

Design and develop a prototype of the Tank Monitoring system, considering as further requirements:

• About the TMS subsystem:
  • it must run on an ESP32 (or an equivalent SoC board).
  • The control logic must be designed and implemented using finite state machines (synchronous or asynchronous) and (possibly, if useful) task-based architectures, exploiting the RTOS.
  • Must use MQTT to communicate with the CUS subsystem.
• About the WCS subsystem:
  • It must run on an Arduino (or an equivalent MCU board).
  • The control logic must be designed and implemented using finite state machines (synchronous or asynchronous) and (possibly, if useful) task-based architectures.
  • It must communicate with the CUS subsystem via serial line.
• About the CUS subsystem:
  • It must run on a PC, as a server/back-end.
  • No specific constraints about the programming/sw technology to be used.
  • It must use:
    • MQTT to communicate with the TMS subsystem.
    • HTTP to communicate with the DBS subsystem.
    • the serial line to interact with the WCS.
• About the DBS subsystem
  • It must run on a PC
  • No specific constraints about the programming/sw technology to be used.
  • It must use HTTP to interact with the CUS subsystem.

For any aspect not specified, you are free to choose the approach you consider more useful or valuable.

The Deliverable

The deliverable consists in a zipped folder assignment-03.zip including 4 subdirectories - one for each subsystem: tms,cus, wcs,DBS) - and a doc subdirectory, including the report. The report must be in PDF or MD (report.pdf or report.md) must include a high-level description of the behaviour of subsystems (using FSMs), a representation of the schema/breadboard and the link to a short video demonstrating the system.