Automatic detectors water tank pump circuit

This is a circuit detectors on the water pump. This circuit works automatically when the water is discharged to storage tanks or redundant. If the storage tank water runs out then the circuit will work running the pump, and an excess of water this circuit will automatically stop the pump working. Below the detection circuit:

Automatic detectors water tank pump schematic diagram

R1                   10K ohms resistor
R2                   10K ohms resistor
R3                   10K ohms resistor
R4                   1K ohms resistor
R5                   10K ohms resistor
R6                   1K ohms resistor
C1                   100nF cap
Led1                5mm green led
Led2                5mm red led
D1                   4V7 zener diode
Piezo               Piezo HPE-120
VR1                78L05 regulator
IC1                  12F683 SOIC microcontroller from Microchip
S1                    Push button
Others:
Box
9V battery
PCB
Metal strips
Hex program for the microcontroller