The post explains a simple water sensor with pump starter circuit for switching a pump motor during municipal water supply periods. The idea was requested by Mr. Hitesh Thapa.
Technical Specifications
Is it possible to make a automatic water pump starter which turns On only when the city supply line has water flowing.
Here is the scenario.
- City Supply Line opens only for 1 hour anytime during 6AM - 10AM or rarely sometimes in the evening depending on the water guy.
- We need to keep a watch during these times and keep the main tap open to see if the water has come.
- Once the water has come, we turn on the water pump attached to the main supply line to pump water into our underground water tank.
Could this be automated, like we install some sensor between the water pump and the main supply line that detects water and turns on the motor only when the supply is in full flow?
I have made the water level indicator at home from watching some videos online and it works fine for the overhead tank at home but this one seems to be tough nut to crack :).
Any help is highly appropriated.
Thanks,
Hitesh Thappa
Circuit Diagram
The Design
The circuit design of the proposed municipal water sensor with pump starter is very simple as may be witnessed in the shown diagram.
A Darlington TIP 122 transistor becomes the main active sensing device in the circuit. The device being a Darlington is very sensitive and thus becomes specifically suited to the application.
Its base and the positive DC are together clamped as probes across the water pipe mouth where the incoming utility water is intended to be sensed.
In absence of water the probes stay separated with air gap which renders a very high resistance across the probes which in turn keeps the transistor/relay stage switched off.
The 10uF capacitor at the base of the transistor ensures that the transistor does not get rattled or disturbed by external noises trying to make way through the sensor wires.
When utility water supply initiates, the pipe mouth begins throwing water into the adjoining tank, the speed of the water through pipe brushes across the probes creating a relatively low resistance across it.
This low resistance allows the positive DC to reach the base of the BJT triggering it into conduction...the transistor now conducts and switches ON the relay, the relay contacts shift position and switch ON the connected pump.
Upgrading the above municipal water sensor into an overhead tank overflow cut off circuit
The discussed circuit in the above section can be appropriately enhanced with an additional feature which will enable the circuit to sense an overhead tank full situation and switch OFF the relay along with the pump motor. The upgraded circuit design can be viewed below:
Deepak says
Hello sir,
As it used 10uf 25 v capacitor in the base of transistor after the resister 1k. wht will happen when capacitor is charged and no water in pipe line than capacitor produce voltage to base of transistor without resister so it will not harm the transistor ?
As we know base of transistor need less than 0.7 v.
Swag says
Hello Deepak, the charge stored in the capacitor will be restricted to a level which is perfectly safe for the transistor base. In fact the voltage level inside the capacitor will be restricted to 0.6V or 0.7V, because the forward voltage drop of most BJTs is restricted to this value therefore the capacitor can charge only upto this limit, so nothing to worry..
Imtiyaz says
Hi Swagatam,
The circuit is working fine. Request you to suggest a suitable modified circuit for eliminating the problem of pump frequently switching on off frequently during the starting few minutes of water supply. I wish once the pump is started should not go off for a couple of minutes even if the sensor are sensing water and air in sequence until the supply is stable.
Hope I am clear.
Thanks in advance.
Swag says
Hi Imtiyaz, I am glad it is working for you!
To solve this you can add a 470uF/25V capacitor across the relay coil, this will make sure that the relay does not stutter during the initial fluctuating water supply conditions.
Imtiyaz says
The shuttering still persist, without resolving continuous practical application is not possible.
As I am a mechanical engineer, request you to forward a complete circuit with discussed modification and introduction of selector switch for auto and manual selection. It would be more asthetic if led indicators are also introduced.
My e-mail id is
imtiyaz_ur@yahoo.co.in
Thank you
Swag says
Hi, did you connect the capacitor across the relay coil? Even after you connect it if the water supply is too much fluctuating with large delays between ON and OFF then the relay will stutter,and cannot be solved with the above simple circuit.
In that case you will have to build a IC 555 monostable circuit and use it.
build the circuit which is shown in the following article
https://homemade-circuits.com/intruder-position-indicator-security/
remove the piezo, and connect the two wires with the water pipe probes.
remove the LED, resistor, and replace it with a relay, make sure to connect a diode across the relay coil.
The 1M pot will need to be correctly adjusted such that the stuttering just stops.
Imtiyaz says
Thanks for the guidance,
All the 3 parts are working
A)Water sensing to start pump
B)Time delay to stop shuttering
C)Overflow pump stopping
Now one small problem, when incoming water stopped#pump goes off
But a slight residue water in the pipe touches the sensor the pump is restarted, how can this issue be tackled?
Swag says
That’s great! I am glad it’s serving the purpose for you.
To solve the present issue, You will have to position the sensor in such a way that the water touches the sensor only when there’s some force in the water, otherwise without any force the residual water should be unable to come in contact with the sensor points.
Ashish Gautam says
Is it not possible to use 12v AC instead of 12v DC ? A transformer could be used to convert 220v AC into 12v AC ?
Swagatam says
It is possible, but the circuit could be come a little complex…
Ashish Gautam says
Complex in what way ? Also, I am not able to find the Tip122 Darlington transistor, is there any substitute for it ? Does relay work in both AC and DC or is there different type of relay for different current ? And will 12v relay work for this circuit ?
Many thanks for the reply.
Swagatam says
You can replace the TIP122 by manually making a Dalington using a 2N2222 and TIP31
A relay will work only with DC, not with AC unless its rectified
I have designed an anti-corrosion related circuit below, you can check it out:
https://homemade-circuits.com/2017/06/anti-corrosion-probes-for-water-level.html
Swagatam says
you ca use the relay which is shown in the following article
https://homemade-circuits.com/2012/01/how-to-understand-and-use-relay-in.html
hemanth hearts says
Hello I want ready ckt is available in any where
Swagatam says
sorry, there's no readymade unit available from here..
john kg says
thank you sir for ur kind advice one more query how much should be the gap need to maintain between the sensor probes and voltage to supply ( our supply pipe is 1.5 inch dia )
john
Swagatam says
the distance could be around 1cm, but make sure that it is built in such a way that water does not clog between this gap when water supply has stopped.
john kg says
good day sir
is it possible to use probe be made off aluminium ( easily avaliable from home utensil) instead of brass ( not easily availiable in my place )
john
Swagatam says
good day john,
you can try the same circuit which is explained above, for indication you can connect an LED in series with the base of the transistor.
for the sensor aluminum will work but aluminum may be also prone to oxidation. instead you can use copper and tin it with a thick layer of solder…the solder should be of the highest grade with a tin/lead ratio of 60/40…or better.
john kg says
good day sir
i need acircuit which detects water flow and giving indication of same when pump starting to fill the overhead tank . we are using pvc pipes and what kind of snsor probs can be used instead of brass for effctive response
john
Unknown says
I want to buy a 'READY TO USE' Controller
which can Switch – On the pump, when it detects
water flow from the City's supply and when
the same stops, it Switch – Off the pump. Has
any company incorporate this circuit design in
their Controller device ? And if so, please list
the name and contact info. Thanks
Sudhir
Gurgaon HR
April 27, 2017
Note: Needless to say, the controller, should have
other features, like Switch Off the pump, when tank
gets filled
Ganesh Budukale says
Respected sir,
as per this circuit diagram and instruction build the same but i dint get result , would u can mail me with details .progressofganesh@gmail.com
Swagatam says
Ganesh, the concept explained is very straightforward and should work without fail, you might have done something incorrect in your design…
you can confirm the results using a cup of water and immerse the sensor points inside it to check whether the relay clicks or not…
Swagatam says
…you can also try reducing the 10uF to 1uF for better response
Meet Patel says
Great. Now this would become Dual functionality embedded in one circuit only. Thanks a lot.
Swagatam says
My pleasure!!
Meet Patel says
Hello sir, have you thought on that new concept which I requested earlier?
Swagatam says
Meet, due to lack of time I could not do it, will try to update it soon…
Swagatam says
….I have updated the new design at the bottom of the article.
Meet Patel says
No problem. Thanks.
Meet Patel says
How should I make water level controller system in this same circuit? So that after filling tank the motor will automatically turn-off, please guide me.
Swagatam says
I'll try to upadte the idea in the above article soon…
Meet Patel says
sorry I made a mistake. There is a single phase motor, not three phase motor. So i got solution. Thanks.
Swagatam says
OK, in that case you can use a regular SPDT relay with 30 amp contacts.
Meet Patel says
As you said I purchased 3 pole relay of PLA company (3C/O MPC 12D-5) having 11 pin encircled. It has 3 pole so on 3 common , 3 N/C and 3 N/O. Now how should I make a connection of 3 phase motor with this relay? please help me out.
Meet Patel says
Thanks a lot. Now I got the whole scenario.
Meet Patel says
should I use single channel relay on 3 phase motor or else double channel relay is suitable for the same?
Swagatam says
for 3 phase motor you will require a TPTT relay or 3-pole relay with heavy duty contacts
Meet Patel says
Ok. Thanks. Because single channel relay can conduct only DC supply.
Swagatam says
relays can conduct AC/DC both, but in 3 phase there are 3 lines therefore 3 contacts would be required, a single contact relay cannot work
Meet Patel says
ok. thank you so much.
Meet Patel says
Hey.. Appreciated your project.
I have one doubt.
What type of sensor probes being used?
Swagatam says
thanks meet, you can use brass terminals with solder plating as the probes.
Faisal Pasha says
Finally I got circuit diagram from Google images, Mr. Swagatam Majumdar can you tell me how much voltages is required to run this circuit because i'm mechanical student I've not enough knowledge about electronics circuit.
Swagatam says
Faisal, you can operate it with 12V… if the relay is also 12V rated, or any voltage that matches the relay coil voltage
Faisal Pasha says
Dear Swagatam Majumdar,
The project (Municipal water supply sensor, pump controller circuit) circuit diagram doesn't show on your site. please send me circuit diagram at email id: faisalpasha9090@gmail.com
thanks!
Swagatam says
Dear Faisal, it could be your ISP problem, please read this:
https://www.linkedin.com/pulse/20140620140349-53089235-blogspot-down-in-pakistan
Zafar Ahmed Abbasi says
very helpful thank you
Nick Hayes says
How much DC voltage do I need for this?
Swagatam says
will depend upon the relay voltage spec used, if it's 12v then the supply can also be 12V and so on.
Swagatam says
you can refer to the following article, the relay explanation along with its specs are provided here
https://homemade-circuits.com/2012/01/how-to-understand-and-use-relay-in.html
Advance Hi Tech says
Required support to repair the electronic circuit