Very simple and fun circuit potted flowers ideal for watering alarm circuit 🙂 Circuit 3-volt battery is working with 1 2N2222 transistor LEDs and two resistors circuit with established flower in the land of water when you pull the LEDs lit irrigation when the LED stops
Simple flower watering alarm test
source http://nurne.blogspot.com/2008/01/water-me-man.html
Handmade Speaker (low power)
It’s an interesting writer HiFi speaker mentioned that it was very simple, but I do not know how much is true for sure. Used in the laptop’s audio output