Combining capacitive soil moisture, temperature, humidity, and motion sensing, this project uses Arduino Nesso N1 to animate a plant pet’s face and leaves based on six moods. It reports data to Home Assistant through ZigBee, offers multiple display and sound modes, and fits inside a sturdy 3D-printed case.

By combining Bluetooth Low Energy for local phone connection and LoRa for long-distance communication, an Arduino Nano and RYLR999 modules let you control appliances remotely without relying on Wi-Fi or internet access.

Decode resistor colour bands in both directions — read the bands off a physical resistor to get its value, or enter the value you need and it returns the bands. Covers 4-band and 5-band resistors, including 1% precision types. Handy for sorting through an old stock drawer when a label has rubbed off, or grabbing the right resistor mid-prototype without squinting at a printed colour chart.

This guide walks you through programming a Raspberry Pi Pico W with Arduino IDE and the ESPAsyncWebServer library to create an asynchronous web server that controls Pico outputs the same way it works on ESP boards.

From an AI aquarium and retro gaming handheld to a bike GPS and smart home Bluetooth proxy, these five ESP32 projects show how you can create cost-effective, fully offline devices without relying on internet or cloud connections.

This project runs on the UNIHIKER K10’s ESP32-S3, recognising electronic parts by capturing brightness-based visual fingerprints from single training images saved in flash. It works fully offline with built-in camera and display, instantly matching objects without any neural networks or cloud dependencies.

From long-range low-frequency through-the-earth signals to short-range high-frequency waves, cave radios cover a range of methods for surface-to-underground contact. Rescue operations depend on these systems, and hobbyists can create their own using basic audio amplifiers and earth-connected antennas, practising safety by testing in controlled environments first.

When input filters add capacitance between op-amp pins, they can trigger overshoot and phase margin drops that lead to instability. You can fix this by calculating a feedback capacitor to cancel the zero frequency, which boosts stability and keeps transient responses in check.

Using a single ESP32-S3 Smart Display module, this project gathers weather info from a BME280 sensor, rain detector, and LDR, then visualises temperature, humidity, pressure, altitude, rainfall, and day/night conditions on an intuitive LVGL touchscreen.

This project uses a TSOP38 infrared receiver and a CD4017 counter to control a 220 V lamp via remote, changing the lamp’s state with every button press. It’s a simple, microcontroller-free way to turn your light on and off from a distance using basic electronics.

Connect a UV sensor and OLED display to an ESP32 C3 inside a 3D printed case, power it via USB, and watch live weather data and UV levels appear alongside changing emoji expressions.

This project blends GPS position and speed with MPU6050 accelerometer and gyroscope data on an ESP32 to calculate velocity via dead reckoning. It uses a Kalman filter and zero-velocity updates to refine speed estimates between GPS fixes, displaying all key navigation stats on a 0.96-inch OLED screen.

This project shows how to create low-power BLE sensors using nRF51822 modules that send JSON data over BLE to ESP8266 WiFi gateways, which then forward the info to MQTT brokers. You can expand the system with LoRa for wider coverage, and it supports various sensors like door, temperature, and pet trackers with battery lives over two years.

The UM 3561 IC creates police, ambulance, fire, and machine gun siren sounds using just a couple of batteries, one resistor, and a driver transistor. It’s a ROM-based chip with a built-in oscillator and tone selection pins, making it super simple to build a siren generator.