SIMUT — Sistema Integrado de Monitoramento Universal e Telemetria

Integrated Universal Monitoring and Telemetry System

Professional-grade IoT firmware for Raspberry Pi Pico W

English | Português | Español

Overview

SIMUT is a professional-grade IoT firmware for the Raspberry Pi Pico W that provides real-time temperature and humidity monitoring through a dual-core architecture. It features a local TFT touchscreen dashboard, an embedded web interface with role-based access control, telemetry upload (HTTP/MQTT), a CLI accessible via USB and Bluetooth, and an externalized language-pack system.

Why SIMUT?

Need	DIY Arduino Sketch	ESPHome / Tasmota	SIMUT
Standalone with display	⚠️ Manual coding	❌ No TFT support	✅ Built-in touch UI
Regulated environments	❌ No audit trail	❌ No user RBAC	✅ Multi-user, audit logs
Cold chain (-80°C to +45°C)	⚠️ Basic readings	✅ Basic monitoring	✅ Calibrated multi-sensor
Offline operation	✅ Yes	❌ Often cloud-dependent	✅ Full local web + display
OTA updates	❌ Manual reflash	✅ OTA	✅ OTA + backup/restore
Security	❌ None	⚠️ Basic	✅ HMAC-SHA256, RBAC, rate limiting

SIMUT is for you if: you need a standalone, secure, auditable temperature monitoring system that works with or without internet — typical in laboratories, pharmacies, blood banks, vaccine storage, and food cold chains.

ESPHome/Tasmota may be better if: you already have Home Assistant, don't need a local display, and prefer YAML configuration over a built-in web UI.

Architecture

┌──────────────────────────────────────────────────────────┐
│ Raspberry Pi Pico W │
│ ┌──────────────────────┐ ┌────────────────────────────┐│
│ │ Core 0 │ │ Core 1 ││
│ │ (Main Loop) │ │ (Display Loop) ││
│ │ │ │ ││
│ │ ◆ AppManager ───────┼──┼─ state/snapshots ──────┐ ││
│ │ ◆ SensorManager │ │ ◆ DisplayManager ◄────┘ ││
│ │ ◆ WebManager │ │ ◆ TouchPriority ││
│ │ ◆ TelemetryManager │ │ ◆ Themes (50 built-in) ││
│ │ ◆ CommandManager │ │ ◆ i18n (PT/EN/ES) ││
│ │ ◆ StorageManager │ │ ││
│ │ ◆ NetworkManager │ │ ││
│ └──────────┬───────────┘ └────────────────────────────┘│
│ │ │
│ ┌──────────┴──────────────────────────────────────────┐ │
│ │ Hardware Interfaces │ │
│ │ ◆ SPI → ILI9341 TFT 320×240 + XPT2046 Touch │ │
│ │ ◆ 1-Wire (PIO) → DS18B20 (up to 16) │ │
│ │ ◆ Data → DHT22 (up to 16) │ │
│ │ ◆ I2C → BME280 T+H+P (up to 8) │ │
│ │ ◆ USB CDC → CLI Serial │ │
│ │ ◆ Bluetooth (BLE) → CLI Remote │ │
│ │ ◆ WiFi (CYW43439) → HTTP Server + Telemetry │ │
│ └─────────────────────────────────────────────────────┘ │
└──────────────────────────────────────────────────────────┘
│ │ │
┌────┴────┐ ┌───┴────┐ ┌────┴───────┐
│ Sensors │ │ Web UI │ │ Telemetry │
│ DS18B20 │ │ Browser│ │ HTTP/MQTT │
│ DHT22 │ │ (RBAC) │ │ Server │
└─────────┘ └────────┘ └────────────┘

Screenshots

TFT Dashboard	TFT Demo	Web UI	Early Alpha

📸 See docs/images/README.md for how to capture screenshots from your device.

🎥 The Early Alpha video shows the first TFT + touch prototype. The UI, themes, responsiveness, and polish have evolved significantly since then — see the current TFT Demo GIF for today's experience.

Hardware

Component	Specification
MCU	Raspberry Pi Pico W (RP2040)
Display	ILI9341 320×240 TFT (SPI)
Touch	XPT2046 resistive touchscreen
Sensors	DS18B20 (1-Wire, up to 10) + DHT22 (ambient)
Buzzer	Passive piezo (PIO-driven)
Storage	2 MB internal flash

See the Wiring Guide for complete pinout and connection diagrams.

Key Features

Sensing & Control

• Multi-sensor support — up to 10 DS18B20 (1-Wire/PIO) + 1 DHT22 ambient sensor
• Zero-trust sensor pipeline — ROM verification every 5 readings, hardware mismatch detection, error hysteresis
• Per-sensor alarms — temperature/humidity thresholds with buzzer melodies and visual TFT feedback
• Web-based calibration UI — calibration mode gated by PERM_CALIB; reference value input calculates offset automatically
• Ambient calibration via picoUID — calib.csv supports custom ID, name, and offsets for the DHT22

Display & UI

• 320×240 ILI9341 TFT — dashboard, real-time graphs, statistics, touch-driven settings (XPT2046)
• Touch-priority scheduler — UI input always wins over background operations
• 50 built-in themes + up to 8 custom themes loaded from LittleFS (offline editor in tools/theme-editor/)
• Dynamic dashboard layout — slot-based, theme-aware
• Atomic screen rendering — canvas-based off-screen compositing, zero tearing
• Sound system — Touch / Confirmation / Error / Alarm / Attention classes with configurable melodies and volume
• Light & dark themes for the Web UI with localStorage persistence

Connectivity & Web

• Embedded web server — multi-user sessions, RBAC (10 permission bits), file manager, live dashboard
• gzip-compressed WebUI — minified inline pages with shared CSS/JS, browser-cacheable
• Self-service password change on the login screen with strength meter
• Telemetry — HTTP POST and MQTT with JSON / CSV / custom templates, TLS/SSL support, adaptive batch sizing
• Multi-sensor history graph — endpoint returning multiple series in one response; configurable range
• CSV export — binary .simx bundle with magic, version, sensor table, records, and CRC32 trailer
• Chunked export with adaptive retry — split on failure with automatic recovery

CLI & Bluetooth

• Dual-channel CLI — USB Serial + Bluetooth with password-protected sessions
• Custom BT device name — configurable via web/CLI
• Deferred-flush logging during BT login to avoid flash contention

Time & Storage

• NTP time sync — exponential backoff, multi-server fallback, virtual RTC with automatic correction
• Manual time entry via Web UI when no NTP is available
• History codec — delta + sensor-mask + anchor encoding for compact binary storage
• LittleFS — CRC32 dual-bank config, history files, rotating compact log

Security

• Hardened authentication — HMAC-SHA256 with per-user random salt, 5000 rounds, 128-bit hash
• Random admin password on factory reset — 8-char shown on TFT, never persisted in flash
• Rate limiter — 16-slot LRU with 15-min TTL, lockout-aware eviction, exponential backoff
• Path-traversal-safe uploads — .., percent-encoding, control bytes and reserved chars blocked
• SECURITY.md with threat model, rotation policy, and incident response

Resilience & Forensics

• Crash forensics — black-box profiler with watchdog scratch register autopsy
• Safe reboot path — USB-friendly reset that keeps the serial port reachable
• Soft-panic detection — cross-core health monitoring
• Watchdog discipline — feeds around every LittleFS operation and during flash operations

OTA Updates

• OTA firmware update — upload new firmware via web UI, applied in-place with config preservation
• Backup & restore — full LittleFS backup/restore with CRC32 integrity verification
• Snapshot-based config preservation — critical settings survive firmware apply

Internationalization

• 2 display languages — English (inline) + Portuguese/Spanish via external language packs
• Hot-loadable language packs from LittleFS
• i18n inline fallback for keys not persisted in device language files

Hardware Requirements

Component	Specification
MCU	Raspberry Pi Pico W (RP2040)
Display	ILI9341 TFT 320×240 (SPI)
Touch	XPT2046 (SPI)
Sensors	DS18B20 (1-Wire) + DHT22
Storage	2 MB flash (1 MB firmware + 1 MB LittleFS)
Buzzer	Passive piezo (PIO-driven)

Quick Start

Prerequisites

• PlatformIO (Core 6.x or later)
• Raspberry Pi Pico W

Build & Flash

# Clone the repository
git clone https://github.com/angeloINTJ/SIMUT.git
cd SIMUT
# Build firmware
pio run -e pico_w_release
# Flash to Pico W (hold BOOTSEL, connect USB)
pio run -e pico_w_release -t upload
# Upload LittleFS data (language packs, favicon)
pio run -e pico_w_release -t uploadfs

First Boot

1. The device boots and shows the setup screen on the TFT
2. A random 8-character admin password is displayed on the TFT
3. Connect to the SIMUT WiFi access point or connect via USB Serial at 115200 baud
4. Log in via the web interface (http://simut.local or the device IP)

Project Structure

SIMUT/
├── src/ # All source code
│ ├── main.cpp # Entry point
│ ├── AppManager*.cpp/h # Application state machine
│ ├── DisplayManager*.cpp/h # TFT display, touch, themes
│ ├── WebManager*.cpp/h # Web server, API, OTA endpoints
│ ├── StorageManager.cpp/h # LittleFS, config, history
│ ├── SensorManager.cpp/h # DS18B20 and DHT22 drivers
│ ├── NetworkManager.cpp/h # WiFi, mDNS
│ ├── TelemetryManager.cpp/h # MQTT and HTTP telemetry
│ ├── CommandManager.cpp/h # CLI parser (USB + Bluetooth)
│ ├── LogManager.cpp/h # Logging and crash forensics
│ ├── SystemDefs*.h # System constants and limits
│ └── ota/ # OTA update subsystem
├── data/ # LittleFS assets
│ ├── favicon.ico
│ └── lang/ # Language packs
├── test/ # Unit tests (Unity framework)
├── tools/ # Build and development tools
├── docs/ # Documentation
├── platformio.ini # Build configuration
├── WebUI.h # Web UI source (compressed at build time)
└── LICENSE

Building

Environments

Environment	Description
pico_w_release	Production firmware (default)
pico_w_debug	Debug build with extra logging
native	Host-side unit tests (Unity)

Build Flags

• -Os — optimize for size (flash is tight at ~98.7%)
• -Wall -Wextra — elevated warnings
• -specs=nano.specs — newlib-nano for smaller binary
• LTO is disabled (toolchain limitation with earlephilhower Arduino-Pico)

Configuration

CLI Commands

A command-line interface is available via USB Serial (115200 baud) and Bluetooth. Key command groups:

• help — show available commands
• conf system — view/edit system configuration
• conf sensor — view/edit sensor configuration
• conf net — view/edit network settings
• conf user — manage user accounts
• write memory — persist changes to flash
• reload — reboot the device

Web API

The device exposes a REST API at http://<device-ip>/api/. See OTA Usage Guide for OTA-specific endpoints.

Documentation

Document	Description
User Manual	Complete hardware setup, display/web/CLI guide, troubleshooting
OTA Update Guide	Firmware update over-the-air via web UI or curl
Recovery Guide	Brick recovery after failed OTA — BOOTSEL and picotool
Security Policy	Threat model, credential handling, incident response
Changelog	Version history and feature changes

Testing

# Run unit tests (validators, CRC, float conversion, time logic)
pio test -e native

Contributing

Contributions are welcome! Please read CONTRIBUTING.md for development setup, code conventions, and the pull request process.

All contributors must follow the Code of Conduct.

Support

• Bug reports:GitHub Issues
• Feature requests:GitHub Issues
• Security vulnerabilities: See SECURITY.md — do not open a public issue
• Questions: Open a discussion or issue

Contributors ✨

Thanks goes to these wonderful people:

Angelo Moises Alves 💻📖🎨🔌🛡️🚧

Lorenzo Longaretto 🧪💻

John Martin 🚇💻

f p 📖

Mike 💻🧪📖

This project follows the all-contributors specification.

Powered by SIMUT

Is your product or project using SIMUT? Add this badge to your README, documentation, or product page:

[![Powered by SIMUT](docs/images/powered-by-simut.svg)](https://github.com/angeloINTJ/simut)

Large version (for presentations, posters, or product packaging):

[![Powered by SIMUT](docs/images/powered-by-simut-large.svg)](https://github.com/angeloINTJ/simut)

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License

MIT License — see LICENSE for details.

Copyright © 2026 Angelo Moises Alves