Add offline voice to a digital multimeter: Arduino + TinyTTS speaks readings instantly, so you can keep your eyes on the probes.

In this tutorial, I am going to talk about the PC817 Optocoupler which is one of the most common and inexpensive 4-pin optocouplers.

THE PROHECT IS COMPLETELY BASED ON THE SURFACE DESIGNING SKILLS ON FUSION 360. I GOT THE BLUE PRINTS AVAILABLE ON THE PORSCHE ORIGINAL WEBSITE. BASED ON THE PORSCHE ORIGINAL DIMENSIONS I CAME UP WITH THE AESTHETIC DESIGN WHICH CONTAIN ALL THE NECESSARY OUTER SURFACE BODY COMPONENTS OF THE CAR BODY. THE HOOD, REAR SPOILERS, HEAD LIGHTS ETC.

Automatische Bewässerungssteuerung für bis zu 4 Pflanzen mit ESP8266 und Home Assistant Integration. ✅ 4x Kapazitive Bodenfeuchte-Sensoren (korrosionsbeständig) ✅ 4x Pumpen mit individueller Steuerung ✅ Wassertank-Füllstandsüberwachung mit Schwimmer ✅ 2x Hardware-Buttons für Standalone-Betrieb Betriebsmodi: • AUTO: Kontinuierliche Überwachung, automatisches Bewässern bei Bedarf • MANUELL: Pumpensteuerung über Schalter • NOTAUS: Automatisch bei leerem Tank Sicherheit: • Interlock - nur 1 Pumpe gleichzeitig aktiv • Timeout-Schutz gegen Überflutung • Keine Pumpenaktivierung ohne Wasser Alle Parameter über Home Assistant einstellbar (Schwellenwerte, Bewässerungsdauer, Intervalle). Komplette Logik läuft auf dem ESP - keine HA-Automationen erforderlich. Hardware: ESP-01, MCP23017, ADS1115, MOSFETs PCB: 2-Layer, 97x76mm, komplett Open Source

This is a 3D printable boat, used to support two 3V DC motor and one Servo motor to turn the sail.

With the new retro-style tuning dial and improved waterfall dynamics, the user interface is now as impressive as the receiver's performance.

Project #28 – Sensors – Grayscale Sensor – Mk20

I built a cheap turntable and obviously I failed. ????

Lightweight ESP32-based IoT module for remote data logging enabling the collection and upload of 3D printing statistic values to a cloud server, as well as displaying them locally on a dedicated display. The project also involves extending the Marlin project by adding a custom G-code command at the firmware level.

A new steering system I designed mainly for Go-Karts.

The OBP40 is an open, cost-effective marine multifunction display, ideal for DIY boat projects and sensor visualization. It's based on the CrowPanel 4.2 with an e-paper display and an ESP32-S3, 8 MB Flash, and 8 MB PSRAM. The system displays numeric and graphical pages with user-selectable values ​​and trends and is operated via buttons. Power is supplied via 5V USB-C. A LiPo battery pack with deep discharge protection and a magnetic dock enables mobile operation. Data communication includes NMEA2000, NMEA0183, 2.4 GHz Wi-Fi, and I2C/1Wire via an expansion port – perfect for integration with onboard electronics and sensors. The open-source firmware is customizable and can be deployed via Wi-Fi or USB. Comprehensive documentation, Telegram support, and wiring diagrams facilitate replication. This makes the OBP40 a flexible, expandable display module for boat data visualization and DIY marine electronics.

A set of 8 pistons with a timing belt and spark plugs.

In this project, I built a simple yet effective variable high voltage power supply using affordable components, offering precise control for high-voltage experiments.

Meet the Manual Universal Testing Machine — a compact powerhouse built for pure mechanical precision. Powered by a smooth hand-crank and guided by dual precision screws, it delivers rock-solid tension and compression testing without electronics, noise, or complications. Engineered with a premium metallic finish and modular fixtures, it turns classroom experiments and lab tests into a hands-on, intuitive experience. Simple. Accurate. Beautifully built. This is material testing—redefined

The DIY Heating Booster helps you get more out of your existing radiator – without modifying your heating system. An ESP32 controls 12V fans mounted underneath the radiator, automatically turning them on when the radiator gets warm to efficiently distribute heat throughout the room. The control logic works standalone with a local temperature sensor, but can also be fully integrated into Home Assistant. Perfect for cold spots, smart upgrades, and energy-saving DIY solutions.