Here is cheap Stereo audio vu meter circuit with PCB. using KA2284 x2 and 10 LED or 5 LEDs per channel, it is simple to builds and few parts. put projects
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
LED VU meter using transistor is analog circuit to show level of power audio signal. You can build 5 LED to 20 LED display with PCB.
This simple moisture meter circuit uses for level moistness temple of the earth. Fine the value R2 give Meter read the value has 1mA. When the moistness [...]
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
The frequency meter by use the LC resonance circuit that adjustable until the frequency show peak amplitude.
Why your circuit does not work? Because the battery is run out. These low voltage indicator circuits may helpful for you. If you can know before and change a new one right now. It makes you not have to waste time when using those projects.