[Need Help]Read circuit,,

Hi,

Can someone please read this circuit about 'automatic watering plant' for me,,

any help appreciated,,

This circuit have been modified by audioguru,,

tqvm

You forgot to ask your question about the circuits.
What do you want to know?

err,,i just want to know the operation of the circuit u have been modified,,so that i can understand it more,,maybe i can try by myself,,

tq in advance,,

The first Cmos Schmitt-trigger gate is an inverter oscillator so that the probes are fed with AC to avoid plating on them which would happen with a DC signal.
The second and third gates produce a pulse-width-modulation output determined by the resistance (wetness) of the soil.
The 47k resistor and 22uF capacitor smooth the PWM waveform into a variable voltage.
the 4th gate triggers the transistor when the voltage drops to its Schmitt-trigger voltage level.
The transistor drives the relay for the watering pump.

The LM3914 is a voltmeter that shows the filtered variable DC voltage which shows the wetness of the soil.

Tq soo much,, appreciate it~~