Build a non-programmable timer without features (aka hourglass)

Feature creep is the phenomenon of adding features to a product or a program that are not necessary for operating the product or program. Examples are colour pickers and font selection options in smartphone apps, and all sorts of other obscure configurable parameters. This little timer does not suffer from feature creep… or does it?

Do you like to know how cold it is outside before getting out of bed? Then this DIY clock is for you. An RPi running a home automation server, an ESP32 with a DHT22 sensor attached to it, and another ESP32 driving an LED display is all you need. Sounds complicated? Welcome to 2018.

These days it's common practice to replace incandescent light bulbs with LEDs, but what if you want to do the opposite? With this converter you can. Simply replace the LED by an optocoupler and let it switch the lamp.

Who realizes this little project gets a device that monitors & displays the current refrigerator temperature, and that logs the time the door was opened and for how long. Alarms can be set on maximum allowed temperature and door-open time.

Arcs in electrical installations are usually the result of loose contacts or damage to cables and conductors. To reduce the risk of a fire, modern houses can use an arc detection switch (AFCI: Arc Fault Circuit Interrupter). This is a device that will interrupt defective circuits when it detects a potentially dangerous electrical pattern. But according to MIT, the present generation of AFCIs are too sensitive and switch off the current to a power point even though the electrical signals are not actually dangerous.

''If you buy my lamp, you won't need drugs'' was the catchy slogan Edward C. Walker used to sell the Astro Lamp he invented in the early sixties of the previous century. More than fifty years later the Lava Lamp as it is more commonly called because of its slowly rising and sinking colourful bubbles still has a substantial share of enthusiasts.

“James, one Martini please -- shaken, not stirred.” This project allows you to ask your personal assistant to prepare your favourite cocktail whenever you feel like it. When the cocktail is ready all you have to do is walk over to the machine and pick it up. You can easily understand why this project won the 2018 ESP32 Design Contest.

Elektor LABS proudly present a new kit to help you assemble your VFD-tube Clock from the article published recently. You’ll build it within about 4 hours, pre-cut acrylic sheet case included, using normal soldering tools and any computer with Arduino IDE. To keep the time synchronised our new VFD-tube clock employs an NTP server. Besides time, it also displays date and temperature in several display formats. Various sensors are supported. The RGB background lighting is user configurable (with a wireless Android app).

Did you know that many projects published at Elektor Labs include the word “simple” in their title? The one we highlight this week is one of them. Reading the project’s description reveals how you can transform a commercially available magnetic door switch into a water detector and alarm by adding just two resistors...

El-cheapo wireless doorbells across the globe are so unoriginal it makes you wonder how much more e-rubbish we can tolerate in and around our homes. Luckily, we electronicz people have the power and skills to design and build our own personalised contraptions, personal here meaning programmable not just at the MCU level but also at the musical level with crude yet original (or not, whatever you prefer) melodies.