🔌 Embedded Systems & ESP32¶

Objective: Build firmware that is safe, power-efficient, and maintainable. These guides cover the real decisions you make when designing embedded systems around the ESP32 — not just "how to blink an LED" but how to architect, power, secure, and ship firmware responsibly.

Guides in this section¶

• Programming Architecture — Event loops, FreeRTOS tasks, state machines, ISR safety, and memory discipline
• Power Management & Deep Sleep — Sleep modes, RTC memory, wake sources, LiPo safety, and designing for sub-100 µA idle
• Hardware & Electrical Safety — 3.3 V logic, GPIO limits, level shifting, grounding, ESD, LiPo dos and don'ts
• Embedded Security & OTA — NVS secrets, secure boot, flash encryption, OTA signing, WiFi credential hygiene
• Sensor Integration — I2C vs SPI vs analog, pull-ups, filtering, calibration, debouncing
• E-Ink Display Integration — Partial vs full refresh, ghosting, SPI wiring, frame buffer design, over-refresh protection
• MQTT Security — Broker hardening, ACLs, TLS, per-device credentials, topic design, NVS credential storage
• LoRa Best Practices (SX127x) — Spreading factor, duty cycle, antenna layout, firmware state machine, AES encryption for raw LoRa
• Safety Checklist (Printable) — Checklist for electrical, power, firmware, RF, and physical safety; print to PDF
• ESP32-S3 and C3 Notes — USB native, RISC-V, BLE 5.0, variant selection, DS/HMAC hardware security peripherals

Applied Tutorial¶

• ESP32 E-Ink Environmental Monitor — Capstone project: BME280 + BH1750 → e-ink display → deep sleep loop on battery power
• ESP32 + MQTT + Home Assistant Integration — Secure sensor node with TLS MQTT, ACL, LWT, and HA auto-discovery

Analytical Context¶

• Deep Dive: ESP32 vs Raspberry Pi — Microcontroller determinism vs Linux convenience: a comparative analysis of power, timing, security surface, and ecosystem trade-offs