Project #15: Environment – EEPROM – Mk25

BathButler is an open-source smart bath filling system that automatically controls hot and cold water valves to fill your bath to the perfect temperature and depth. It features a two-board architecture: an ESP32-S3 relay controller (Waveshare) handles valve control, temperature sensing, and safety logic, while the CrowPanel 1.28" Rotary Display provides an intuitive physical interface — just twist the knob to set your temperature, click to start. The system includes a real-time circular web dashboard accessible from any phone, Amazon Alexa voice control, over-the-air firmware updates, automatic WiFi setup with captive portal, and a flow rate calibration system for depth estimation without a level sensor. Safety features include overheat cutoff, watchdog timer, and valve protection. All interfaces share a common REST API + WebSocket backbone, with a Flutter mobile app in development.

This innovative project is a robotic lion model made entirely using e-waste and recycled materials. It uses an ultrasonic sensor to detect nearby objects (within 2 meters), responds with a realistic roaring sound, and wagging tail movement through a servo motor. Designed to encourage sustainability and creative reuse of discarded electronics, this project blends environmental awareness with practical electronics and coding skills, making it perfect for student learning and STEM outreach.

This small project can be interesting for beginners in electronics or robotics.

Stop using clunky physical buttons for your Arduino projects. Instead, why not use the TTP223 capacitive touch sensor.

eBUS Adapter Stick C6 is a reduced size version of previous highly demanded eBUS Adapter Shields and provides an interface to a 2-wire eBUS with galvanic isolation for enabling communication with an eBUS enabled heating, ventilation or solar system. With a size of 42 x 16 mm it is way smaller than the previous Shield versions, but still supports an USR-ES1 module being plugged onto it for having Ethernet access. Even better, with the upcoming firmware version for the ESP32-C6, it automatically scans the heating components and makes all data available via MQTT to e.g. Home Assistant with auto discovery of entities.

It uses free API key with Live ADS-B data, presented in a beautiful visual display with smooth animation, and a custom-built radar interface.

One of the best Chinese produced Energy Monitor ASICs now easier than ever to use

A project for automation, hobby and also learning.

This is a small (17.9 mm x 10.3 mm) breakout board for PixArt's PAA3905 optical flow sensor. It provides X-Y velocity at 126 Hz via Optical Flow and 35 x 35 pixel video camera at 18 Hz. There is a well-commented Arduino sketch showing how to use the device for navigation and frame grabbing. The frame grab rate is significantly improved over its predecessor, making for a practical low-resolution still imaging and video camera capability. Power usage is a modest 3.5 mA and the sensor can move in and out of shutdown mode quickly allowing flexible power management. The light level adjustment is automatic (although can still be done manually), streamlining sensor management. The sensor is smaller than its predecessors, with fewer pins making design and assembly easier. Light level sensitivity extends down to 5 lux. The frame grab occurs at a crisp ~15 Hz (56 milliseconds to complete), allowing low-resolution video imaging using the infrared-sensitive sensor element. Open source design!

How to spy on your neighbor (scientifically)? Acoustic parabola + NLMS on ESP32.

The Self-Balancing Robot is a two-wheeled mobile robot that uses control theory and sensor feedback to maintain its balance, similar to how humans balance on two legs. It demonstrates fundamental principles of robotics, mechatronics, and control engineering. This project is designed as an educational tool to learn about sensors, actuators, control algorithms, and embedded systems.

Elecrow 3.5" HMI ESP32 TFT using a Dallas DS18B20 to easily get temp data displayed upon the TFT.

This guide describes how to build the XIAO METER demo board, designed to easily test a wide range of sensors using the XIAO SAMD21 by Seeed Studio, the smallest member of the Seeeduino family. The module measures only 20×17.5×3.5mm, and features a Cortex-M0 microcontroller, 11 I/O pins, and supports UART, I2C, and SPI communication. It is fully compatible with the Arduino IDE.

Take a temp sensor and build it!