Around spring 2020 I suddenly saw a lot of magically in the air standing objects. After a closer look one could always see the ropes,...

After hearing about the HC-12 operating distance over a kilometer, I wanted to test it by myself. What kind of information one sends is...

It is a USB charger that turn complacently off after 3.5 hours. After one presses the power button (the red one) a relay is turned ON and...