This is simple Solar plant watering alarm circuit. It will sound alarms when the soil is dry. The trees have died. It the solar sell is 6V DC power supply
Include: Volt meters :: Sound level meter :: Analog vu meter :: Soil moisture meter :: Digital meter circuit diagram :: Temperature measurements :: Electronic measurement tools :: Frequency meters :: Best battery tester :: Transistor tester project
These are Five Battery low voltage alarm indicator circuits, as ideas to make small projects, them use LED display easy, cheap with normal parts look below [...]
This is the Transistor tester circuit into PCB. When your project do not works, the tester electronic parts or component be what need very much.