Access control systems are commonly used in offices, schools, laboratories, apartments, and industrial facilities. At the center of these systems is a controller that decides whether a person is allowed to enter, controls the door lock, and monitors alarm inputs. In this tutorial, I will build a small access control …

When I first moved from ultrasonic sensors to Time-of-Flight (ToF) sensors, the difference was night and day. Measurements became faster, more stable, and far more precise. In this tutorial, I’ll show you exactly how I use a ToF sensor like the VL53L0X with the ESP32. What is a Time-of-Flight Sensor? …

If you are building a smart agriculture project, one of the most useful things you can measure is the nutrient condition of the soil. Moisture sensors can tell you if the soil is wet or dry, but they cannot tell you whether the soil still has enough nutrients for healthy …

In this project, I’ll show you how I interface the ESP32 with the INMP441 I2S microphone module, starting from basic audio capture and then moving toward a more interactive application where the sound is visualized in real time on a web browser. When I first worked with microphones on microcontrollers, …

When I first started working with sensors, I expected clean, stable readings. Instead, what I got were values jumping all over the place. A temperature sensor would fluctuate ±2°C, an ADC reading would jitter constantly, and analog signals were almost unusable without processing. That’s when I realized: raw sensor data …

Running Bluetooth Low Energy (BLE) scanning and Wi-Fi networking at the same time on an ESP32 sounds straightforward—until it isn’t. Many developers discover that once BLE scanning starts, their Wi-Fi web server becomes unreliable. Pages load intermittently, HTTP requests time out, or BLE scans suddenly stop when Wi-Fi traffic increases. …

Motion detection usually means PIR sensors, cameras, or microphones. ESPectre takes a very different approach: it detects movement by analyzing how the human body disturbs Wi-Fi radio waves. Interestingly, many modern signal-processing systems — from Wi-Fi sensing to broadcast monitoring infrastructures like this Thor Broadcast deployment — rely on analyzing …

In this tutorial, I’ll show you exactly how I send sensor data from an ESP32 to Google Sheets every hour.

If you’re looking for a simple but powerful way to control AC or DC devices over Wi‑Fi, the ESP8266 relay board is one of the best places to start. I’ve used ESP8266‑based boards in many hobby and semi‑professional projects, and relay boards are usually the first real‑world application people build.

In this tutorial, I’m going to walk you through how I built my own voice assistant—similar to Alexa or Google Home—using only a Raspberry Pi 5, a USB microphone, a speaker, and an LLM with text-to-speech (TTS) and speech-to-text (STT) support. By the end of this guide, you’ll have a …