themaccabee
Full Member level 4
Hi i was trying to make a simple water level indicator.The circuit is shown below
(taken from redcircuits.com)
I assmebled the project in two small PCBS.Its working well when the three leads from 4012 are shorted and tested.
The arrangement i made inside the water is as follows ---from the three leads three insulated breadboard wires of separate lengths are taken and they are tied to a rod together.The tip of insulated wires are removed of insulation so that when water touches the contacts should be shorted.The setup is shown below.
The problem is when the arrangement shown above is under water..Minimum (red) LED works well.In Medium Level the (Yellow) LEDis on for some seconds then switches off.In the Full Level the LED (green) is never turned on at all..
So what should i do?They ve said in the circuit description to use steel rods ,but since ive none with me i used this arrangement.Can somebody tell me where i m wrong.
Thank you very much
Stephen.
Code:
Parts:
R1,R2,R10-R12___15K 1/4W Resistors
R3,R4____________1K 1/4W Resistors
R5_____________100R 1/4W Resistor
R6______________47K 1/4W Resistor
R7,R8,R13________3K3 1/4W Resistors
R9,R14,R15_______2K7 1/4W Resistors
C1_____________470nF 63V Polyester or Ceramic Capacitor
D1_______________3mm Green LED
D2_______________3mm Yellow LED
D3_______________3mm Red LED
Q1_____________BC547 45V 100mA NPN Transistor
IC1_____________4012 Dual 4 input NAND gate IC
IC2____________LM393 Dual Comparator IC
J1,J2____________Two ways output sockets
P1______________SPST pushbutton
B1________________9V PP3 Battery
Clip for PP3 Battery
Two steel rods of appropriate length(taken from redcircuits.com)
I assmebled the project in two small PCBS.Its working well when the three leads from 4012 are shorted and tested.
The arrangement i made inside the water is as follows ---from the three leads three insulated breadboard wires of separate lengths are taken and they are tied to a rod together.The tip of insulated wires are removed of insulation so that when water touches the contacts should be shorted.The setup is shown below.
The problem is when the arrangement shown above is under water..Minimum (red) LED works well.In Medium Level the (Yellow) LEDis on for some seconds then switches off.In the Full Level the LED (green) is never turned on at all..
So what should i do?They ve said in the circuit description to use steel rods ,but since ive none with me i used this arrangement.Can somebody tell me where i m wrong.
Thank you very much
Stephen.