Firmware
Real-Time Operating System (RTOS): FreeRTOS on ESP32
A beginner-friendly guide to using FreeRTOS on ESP32 for multitasking firmware with tasks, queues, notifications, mutexes, and practical debugging habits.
6 min read
Notes
Technical articles for small products.
Latest build log
5G IoT with ESP32: Connect NB-IoT & LTE-M from Modem to MQTT
A practical ESP32 guide to integrating an NB-IoT/LTE-M modem: choose the network, power it safely, wire UART, use TinyGSM and send first telemetry.
Firmware4 min read
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All (52)Hardware (9)Firmware (29)PCB Design (7)Embedded UI (4)Product Design (3)3D Printing (0)Mochi (0)
Firmware
Industrial IoT with ESP32: Modbus and Real-Time Control
A practical guide to Modbus TCP, Modbus RTU over RS-485, and PLC communication with ESP32 for reliable industrial IoT prototypes.
7 min read
Firmware
Over-The-Air (OTA) Firmware Updates: Design & Implementation
A practical guide to designing safe OTA firmware updates for ESP32 and STM32, covering partitions, signed images, rollback, rollout control, and delta updates.
8 min read
Firmware
RISC-V Embedded Development: Getting Started with ESP32-P4
A practical ESP32-P4 RISC-V guide: install ESP-IDF, select the esp32p4 target, build a first project, flash over USB, and understand the dual-core architecture.
7 min read
Firmware
STM32 Beginner - P3: UART, I2C, and SPI with HAL
Learn the three common STM32 interfaces: use UART for debugging, I2C for sensors, and SPI for displays or memory with STM32CubeIDE and HAL.
9 min read
Firmware
STM32 Beginner - Part 5: Building a Complete Application
Combine timer, ADC, DMA, PWM, I2C, and UART into a small STM32 bench monitor with a clear firmware architecture, fault handling, and room to grow into a real project.
12 min read
Firmware
STM32 Beginner Guide P2: GPIO, Interrupts, and Timers from the First Example
Learn to configure GPIO, capture a button event with an EXTI interrupt, and create a periodic time base with a timer on STM32CubeIDE using a NUCLEO-G071RB board.
8 min read
Firmware
STM32 Beginner Guide P4: ADC, PWM, and DMA from Analog to Continuous Data
Learn to read analog signals with ADC, control LED brightness with PWM, and transfer multiple samples through DMA on STM32CubeIDE using HAL.
8 min read
PCB Design
GPT-6 Astra and the Future of PCB Design: Speed Up or Replace Engineers?
How far can GPT-6 Astra go in KiCad? An independent look at the demo, EEBench, open-source tools, and why routing a board is not the same as making it production-ready.
7 min read
Hardware
HC-05 vs HM-10 vs BLE 5.0: Which Bluetooth Module Should You Choose?
Compare HC-05, HM-10, and BLE 5.0 modules by Bluetooth Classic, BLE GATT, UART, phone support, range, power, and integration for Arduino, ESP32, and IoT projects.
6 min read
Firmware
nRF52840 BLE Wearables: How to Build a Wearable Device
A practical guide to building nRF52840 BLE wearables with open-source references, Zephyr, compact GATT design, sleep/wake states, and real power measurements.
6 min read
Firmware
STM32 Beginner Guide P1: What Is STM32 and Which Board Should You Choose?
Learn what STM32 is, distinguish chips, modules, and development boards, then choose a practical board for learning GPIO, HAL, STM32CubeIDE, and embedded firmware from the beginning.
8 min read
Firmware
Which Wake Word Is Better? microWakeWord vs Google vs Alexa
A practical comparison of microWakeWord, Google Assistant, and Alexa by architecture, control, privacy, hardware fit, and ESP32-S3 integration.
7 min read
Firmware
ESP32 Beginner Guide – P5: Wi-Fi and Web Server
Connect ESP32 to Wi-Fi, find its IP address, and build a local web server that displays BME280 temperature, humidity, and pressure in a browser.
4 min read
Firmware
ESP32 Beginner Guide – P6: Bluetooth Low Energy
Learn ESP32 BLE, GATT services, and characteristics by sending BME280 readings to a phone with Read and Notify.
5 min read
Firmware
ESP32 Beginner Guide – P7: Build a Complete ESP32 Project
Finish the series with a Room Comfort Monitor: ESP32 reads a BME280, controls a warning LED and serves a local Wi-Fi dashboard.
5 min read
Firmware
ESP32 Beginner Guide – P4: Connecting Sensors
Connect digital, analog, and I2C sensors to ESP32; read temperature, humidity, and pressure from a BME280 and diagnose devices that are not detected.
6 min read
Firmware
ESP32 Memory Management Deep Dive: SRAM, PSRAM, Heap and FreeRTOS Stacks
A practical ESP32 memory guide covering SRAM layout, PSRAM usage, heap fragmentation, RTOS task stacks, and small optimization tricks that are useful in real firmware.
5 min read
Firmware
ESP32 Beginner Guide – P3: Pinout and GPIO
Read an ESP32 pinout, choose GPIO for input and output, use pull-ups, wire an LED and button, and avoid boot, flash, PSRAM, and unsafe 5 V signals.
7 min read
Firmware
ESP32 IoT Project Roadmap: From LED to Production
An interactive ESP32 project roadmap from LEDs and buttons through connected sensors and edge ML to production OTA and security, with practical guides at each level.
5 min read
Hardware
ESP32 Beginner Guide – P1: What Is ESP32 and Choose ESP32
Learn the difference between ESP32 chips, modules, and development boards, then choose an ESP32-C3, ESP32-S3, or classic ESP32 board without buying hardware you do not need.
9 min read
Firmware
ESP32 Beginner Guide – P2: Setup and Upload Your First Sketch
Install Arduino IDE and Arduino-ESP32, select the correct board and port, upload your first sketch, and fix Failed to connect errors on ESP32, ESP32-C3, and ESP32-S3.
6 min read
Firmware
18 Common ESP32 Errors – Part 2: Critical Errors
How I read ESP32 backtraces and troubleshoot crashes, watchdogs, heap, stack, FreeRTOS, Wi-Fi, ADC, deep sleep, and OTA with a practical runtime checklist.
12 min read
Hardware
18 Common ESP32 Errors and How to Fix Them – Part 1
How I troubleshoot eight common ESP32 problems: flashing, boot mode, brownouts, serial, GPIO, I2C, SPI, and custom PCB bring-up.
9 min read
Firmware
Wake-word detection: always-listening smart devices
A practical look at local wake-word detection on ESP32-S3 devices: audio framing, microWakeWord, threshold tuning, false activations, microphone mute, and privacy.
5 min read
Firmware
Local-first architecture: keeping data off the cloud
A practical local-first architecture using an on-device store, Automerge, optional sync, and backups so an app stays useful without sending its working data to a cloud service.
4 min read
Firmware
Running Linux on ESP32-S31: What the MMU Changes
ESP32-S31 now has an official Linux BSP Developer Preview. Here is a practical look at its MMU, Buildroot, U-Boot, Linux 6.18, build flow, and the limits that still matter.
6 min read
Firmware
TinyML on ESP32: Running AI on the Device
How I run a small person-detection model on ESP32 with TensorFlow Lite Micro and ESP-NN, from memory limits to testing Espressif's example.
5 min read
PCB Design
Net Classes and Trace Width: When Should a PCB Trace Be Wider?
A practical guide to PCB net classes and trace width for small boards: signal traces, 3V3, 5V, battery paths, ground, power vias, and a pre-Gerber checklist.
9 min read
PCB Design
PCB Ground Planes: GND Is More Than a Net Name
A practical guide to PCB ground planes, return current, GND layout mistakes, stitching vias, decoupling paths, and copper pour checks.
8 min read
Hardware
What Is a MEMS Microphone? From a Silicon Diaphragm to ESP32 Audio
Learn how MEMS microphones work, how analog, PDM, and I2S outputs differ, and how to avoid PCB, power, and acoustic-port mistakes.
8 min read
PCB Design
Choosing Capacitors for Electronics: Simple Part, Easy Mistake
A beginner guide to choosing capacitors for circuits: capacitance, voltage rating, decoupling, ceramic types, DC bias, and ESP32 values.
8 min read
PCB Design
How to Hand-Solder SMD Components for Beginners
A beginner-friendly SMD soldering guide covering tools, easy parts, resistors, capacitors, multi-pin ICs, flux, hot air, and PCB inspection.
8 min read
Hardware
ESP32 Battery Power Design: From USB-C Charging to the 3.3V Rail
Review an ESP32-S3 battery power path from USB-C and TP4056 charging to protection, load sharing, 3.3V regulation, and load budget.
12 min read
Firmware
Extending Battery Life in an ESP32 Robot with a Display
Analyze battery life for an ESP32 robot with a display: backlight, Wi-Fi, audio, peripherals, sleep modes, wake sources, and runtime.
9 min read
Firmware
Designing an Emotion State System for the Mochi Robot
Build a Mochi Robot emotion state machine for idle, listening, talking, happy, sad, thinking, and error states with replaceable animations.
7 min read
PCB Design
A Practical PCB Review Checklist Before You Send It to Fab
A practical PCB review checklist before fabrication: schematic, ERC, footprints, clearance, power, antenna, USB pairs, silkscreen, Gerbers, and BOM.
6 min read
Embedded UI
Displaying Expressive GIFs on ESP32 with LVGL
A practical guide to animated GIF expressions in ESP32 firmware: convert assets, enable LV_USE_GIF, store files, and render with lv_gif.
4 min read
Hardware
ESP32-C3 or ESP32-S3: Which Chip for a Robot with a Screen and Audio?
Comparing ESP32-C3 and ESP32-S3 on GPIO, RAM, PSRAM, USB, I2S, and LVGL headroom, with a concrete recommendation for a basic Mochi build and a Mochi AI build.
5 min read
Embedded UI
GIF, PNG, JPG, or a C Array: Which Image Format Fits Your ESP32 Screen?
Compare GIF, PNG, JPG, and C array images for ESP32 displays by flash use, RAM use, decode speed, alpha, animation, and quality.
6 min read
PCB Design
Reading an Open-Source ESP32 Schematic Before Reusing It
An ESP32 TouchDown case study for reviewing an open-source schematic before reuse, covering power, reset, boot, USB, connectors, and tests.
6 min read
Firmware
Two-Way I2S Audio on ESP32-S3: I2S Microphone and I2S Speaker
A practical explanation of BCLK, WS, DIN, DOUT, full-duplex audio, sample rate, and buffers when building two-way I2S audio on ESP32-S3.
6 min read
Hardware
Complete Hardware Architecture for an ESP32-S3 Mochi Robot
A practical breakdown of ESP32-S3 Mochi Robot hardware: display, touch, I2S microphone, amplifier, speaker, battery, charging, and GPIO.
5 min read
Embedded UI
LVGL and Mochi Robot: Building Emotional Interfaces for Embedded Devices - Part 1: The Power of LVGL in UI/UX Programming
How LVGL helps build emotional interfaces for Mochi Robot, including expressions, menus, battery status, and UI on small embedded displays.
4 min read
Hardware
LVGL and Mochi Robot: Building Emotional Interfaces for Embedded Devices - Part 2: Mochi & LVGL
Part 2 of the Mochi LVGL series, covering faces, expressions, battery status, connectivity, screens, components, and UI states.
6 min read
Embedded UI
What Is Embedded UI, And Why It Matters
What embedded UI means for small devices, why small screens have small budgets, and why it deserves attention as its own discipline.
4 min read
Firmware
First Notes On Firmware For Embedded Products
Early principles for firmware on a small embedded product: scope, module boundaries, logging, and handling errors without guessing.
4 min read
Product Design
Mochi Devlog 01: Early Development
The first Mochi devlog: early hardware questions, first firmware decisions, and what already went wrong.
3 min read
Product Design
What Is Mochi?
A short introduction to Mochi, a small robot developed as an exercise in hardware, firmware, and product experience.
3 min read
Hardware
First Notes On Hardware Design For Small Products
Initial principles for designing hardware for a small product: scope, power, PCB layout, firmware, and debugging.
3 min read
Product Design
How Free Design Resources Will Be Shared
How Nastrotek prepares and shares design files, templates, source code, and free documents clearly.
3 min read
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