Semi Automatic Water Level Timer/Controller Prototype Built by Mr.Raj Mukherji, (Images)

The water level timer/controller circuit which was designed and published by me in one of my previous articles was successfully built and tested by one of my friends Mr.Raj Mukherji, who is also an avid reader of this blog, and a keen electronic enthusiast.



Here's the email that he sent to me explaining everything regarding the working of the circuit:

Dear Swagatam,

Finally I have managed to build, the model of this semi automatic timer project which is given below:

http://www.use.com/9be8549fa77bb7793263

There were only three modifications I made:

1. Connected an LED to pin 7 in order to get a visual indication of the oscillation.
The LED starts to blink after 20 secs of powering the timer on
2. Used four diodes for full wave rectification instead of just a single diode for
smooth DC input
3. Added 22Mfd capacitor between pin 12 and 16 instead of 0.22Mfd because 0.22Mfd was
not allowing the oscillation to begin when the circuit was drawing power from the
transformer. However, 0.22Mfd did not make any problem when the power was fed from
a 9 Volt battery

I have found that with the given values of the R and C, the range of this timer is between 1 - 30 mins.

I have also found the formula to calculate the frequency of the timer (it is found to work correctly to a certain extent practically):

F in KHz = 1 / {2.3 x (R2+P1) x C1} where, R2 & P1 in K Ohms, C1 in Mfd

1
Time Period (TP) in milisecs = ------------ where, F in KHz, Q(n) as shown below.
{F / Q(n)}

Pin7 = Q(4) -> divided by 16
Pin5 = Q(5) -> " " 32
Pin4 = Q(6) -> " " 64
Pin6 = Q(7) -> " " 128
Pin14 = Q(8) -> " " 256
Pin13 = Q(9) -> " " 512
Pin15 = Q(10) -> " " 1024
Pin1 = Q(12) -> " " 4096
Pin2 = Q(13) -> " " 8192
Pin3 = Q(14) -> " " 16384

Example: If P1 is set at 15 KOhms, R1 = 1 KOhm, C1 = 1 Mfd and we select the output from Pin3 (which is Q14) then:

1 1 1
F = -------------------- = ------------------ = ------------ = 0.0272 KHz
{2.3 x (R2+P1) x C1} {2.3 x (1+15) x 1} 36.8


where, F = Clock frequency of the timer

Then, the frequency at Pin3 of the IC will be: 0.0272/16384 = 0.00000166 KHz

Therefore, Time Period (TP) of the timer is: 1/0.00000166 = 602409.6 miliseconds
= 602.41 secs
= 10.04 mins

[NOTE: Time Period = ON time + OFF time]

Hope this will help my co-readers to understand the working of the CD 4060 better.

Thank you,
With warm regards,
Raj Kumar Mukherji

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