Hello friends

Today I am back with another project called $1 AUTOMATIC WATER LEVEL CONTROLLER.

It’s an automatic switching circuit that used to control an AC water pump. Operation of this circuit is simple.wen the water level goes below the limit the lower level sensor will detect it and activate the water pump.wen the water level reaches the upper limit the upper limit sensor detect it and switch of the water pump.

Step 1: My Goal

Picture of My Goal

“To make a cheap but efficient water level controller under $1 budget to control AC water pump”

Step 2: The Circuit

Picture of The Circuit

This is the driving circuit of the $1 AUTOMATIC WATER LEVEL CONTROLLER.

To make this circuit you will need

  1. BC 547 Transistor X 3 = 9 INR
  2. 220 K Ohm & 5.4 K Ohm resistors = 1
  3. 1N4007 Diode = 1
  4. 12V relay = 12
  5. One, 3-pin PCD connector & two, 2-Pin PCB connector = 25
  6. Wires = 5
  7. PCB = 12

Total = 66 INR

Total cost of this circuit is equals to 66Rs or 66INR (66.6 INR = 1 USD).that means this circuit is under the $1 budget

12v relay is the main component of this circuit, so please use a relay with 7Amp or more. I am using a 12v can handle 7 Amp AC @240v.

Step 3: The Sensor

Picture of The Sensor

To make sensor you don’t need anything special. Take three wires and name them like LOW, HIGH AND MAIN. Place “MAIN” on the bottom of the tank. Then place “LOW” above the outlet. Finally place “HIGH” on the top of the water tank

[ ~~~~~~~~~~~~] -------------------------------------- “HIGH”

[~~~WATER~~~ ]

[ ~~ TANK ~~~~~]

[~~~~~~~~~~~~ ]

[~~~~~~~~~~~~ ]--------------------------------------- “LOW”

[______________]--------------------------------------- “MAIN”

This is the placing order of the sensors

Step 4: ​Connect Them All

Picture of ​Connect Them All

Connect all wires to the main circuit board with help of circuit diagram. Double check all connections because playing with high voltage is DANGER

Step 5: The Moment of Truth

This video show how $1 AUTOMATIC WATER LEVEL CONTROLLER work


Prince FloroS (author)2017-11-22

Well done. I have a question is it ok if I use 220v @ 30amp Water Pump with this Controller? Thank you.

vina1991 (author)Prince FloroS2017-11-22

unfortunately no, because the relay cant handle more than 10 Amp

MoHart (author)vina19912018-01-01

If u use a relay capable of taking 30 amp then use the circuit to switch the relay which will in-turn switch-on the 220v pump The 220v pump is wired seperately with heavier gauge wire.

KmiloG1 made it! (author)MoHart2018-01-14

What you can do is use a Contactor, which you activate with that relay that is already there, since the contactor is activated is with 110 volts and the contactor activates the load you want.

Note: The contactor is like a relay but it supports loads much greater than a relay.

pritimoy made it! (author)2017-11-08

Working fine. Now need to test in original tank.

vina1991 (author)pritimoy2018-01-03

thank you for your support :)

pritimoy (author)pritimoy2017-11-08

ravijag (author)2017-11-07

Nice and simple! Reminded my hobbyist days years back!

Any mod to include logic/circuit to support an underground sump so that the motor runs only when there is sufficient water in the sump?

vina1991 (author)ravijag2017-11-08

definitely yes,but you need to tweak the circuit little bit

ahmed_123w (author)2017-10-31

Hi ihave made the circuit its working but there is one problem when all the sensor main + low + high are connected it stops but when main + low are connected it starts before the low is disconnected what to do

vina1991 (author)ahmed_123w2017-11-01

please check the circuit diagram given below :)

AliB128 (author)2017-10-12

can anyone help me with circuit diagram please

vina1991 made it! (author)AliB1282017-10-12

definitely yes

i think its the time to make a youtube channel to explain my project

AliB128 (author)2017-10-07

Circuit diagram picture please

IfeanyiA2 (author)2017-07-03

Vina, as far as i'm concerned you are the best in teaching me electronics,

pls. do reply me anytime i call on you i love you. But i am out off town for now till weeks i will send the picture immedietely i come back as you instructed, pls be my mentor.

IfeanyiA2 (author)2017-07-02

okay, i will do that.

IfeanyiA2 (author)2017-07-02

Hi Vina, i really love your projects, i just finished making the automatic water level control but the problem i get is that the motor only activate when i touch the probe not when i put it in the water. what could be the problems pls. i need your help.

vina1991 (author)IfeanyiA22017-07-02

i IfeanyiA2
thank you for your support :)

can you please sent me the pictures of your circuit? i think i can help you :)

Bundolo (author)2017-02-22

Hi. Nice circuit. How large a tank will this work on (ie what is the maximum distance between the probes)?

abdulb68 (author)2016-11-16

is it applicable for 1 hp Submersible Pump as well?

pls repaly me as possible

octebra (author)2016-11-10

Hi Vina, great project have just finished it but have a problem the relay activates when I touch the wires with my fingers but not in water. Will changing the resistor on the main terminal fix this, if you could help I would really appreciate it again a great project. I am using it to keep a fish pond full with a 12v solenoid valve.

polmourgos (author)2016-11-04

Thank you for sharing this project.

vini1167 (author)2016-08-24

Hi Vina ,

Nice Useful Project !!

Please advice me the Ratings for the Power Supply for this Circuit while using A Relay of 12V / 7 Amps .

Thanks Again

vina1991 (author)2016-05-01

Thank you for your positive feedback

Hi vina, can you please give me your WhatsApp number? Or your Google + profile

djfreestyle80 made it! (author)2016-07-23

Done..!, I've made it..after few try Wire (Probe) Connection Combination with MultiTester on Relay Connector, I got result like this :
1. Main - Lower - High = Relay Start Sound + Multitester Nail Moving, its indicating if water below Low Level Pump Motor Start "On" (NC State)
2. Main + Lower - High = Relay Stopping Sound + Multitester Nail Keep on Steady measurement like before (No.1), it's indication Pump Motor Still "On" (Still NC State)
3. Main + Lower + High = Relay Sound "Clicking" + Multitester Nail Moving to Beginning Value, it was indicate Pump Motor "Off" (NO State) and Loop again to No.1

Here some Spoiler for Pic :

vina1991 (author)djfreestyle802016-07-23

thank you for trying my circuit :)

djfreestyle80 (author)vina19912016-07-31

after real implement to water, i have a different result at step 3 that motor should stop after 3 wire connected, if I connected 3 wire directly per step it's worked!, but after i dipped 3rd water into water, relay still at NC state indicate motor still on, was it depend on water conductivity level..?

vina1991 (author)djfreestyle802016-08-02


yes, may be.water is not a poor conductor of electricity.the impurity and minerals are give the conductivity to water.may be filtered water can't conduct the tiny current given by the circuit.


now i am trying to use a safer version of AWLC without touching water with probes or wires sooz i will fins a soilution

djfreestyle80 (author)vina19912016-08-03

Ok thanks for your feedback vina..I think that's so cool you can make AWLC sensor without touching the medium..hmmm..sonic wave maybe..I will waiting fo your update:-)

Sir I m waiting for ur response.. kindly help me through this

i am sorry from the bottom of my heart :( i am busy with "call of duty" ( not the game.i mean the job)

Q1 :

i think, maybe there is an issue.the the circuit detect very minute current in the maybe WLC get confused.try a test yourself :)

Q2: can use same PS for 2 circuits f your power supply use same voltage and plenty of current .but in your case,you are going use 5v 1A power supply to power up 9V Indicator and 12v AWLC same time how is this possible?

djfreestyle80 (author)vina19912016-07-23

Me thanx to you igniting an Inspiration:-D, if u don't mind I have two questions, first I have a circuit consist of four led Water Indicator using four Steel Bolt as water probe and has charged with 9V PS in my tank, so the questions, can I Join or share the probes with your circuit made..?, my plan will use DC-DC Step Up from 5V 1A later separately as PS, or they can be joined as share PS?, Newbie here so need more light:-D, thanks again.

automated_engineer (author)2016-07-31

is it applicable for 1 hp Submersible Pump as well? and kindly give me a rough sketch on how to connect it with the starter box..

sorry buddy.i don't know how to wire up a Submersible Pump jut because i cant find submersible pump near to my home.may be a local electrician can help you to wire up

shanawera (author)2016-07-14


i am making this circuit but confused with the current required to drive the circuit.

i am using a 12-0-12 v 500mA step down transformer .will this work???need help

vina1991 (author)shanawera2016-07-14

this circuit only use 30 mA at idle stage and 250~300mA at full load(relay is on)

so you can use 12v 500mA power supply.

avoid using LEDs as indicator, they need 30mA current or use 1A power supply.

RafaMemphis (author)2016-05-02


Great ible, but if i need to control the well? when its full the pump could start and when its low the pump has his power off? what modification i need to make in this project?

Sorry my english!

electronhick (author)RafaMemphis2016-07-09

Hello, I believe the solution you are looking for is very simple. Build the circuit exactly the same, except when you are placing the wires in the water reservoir, reverse the wire positions so the low level will be the high wire and will turn the pump on, and the high level will be low water and will turn the pump off when it reaches the bottom. I haven't built this yet but I plan on it and trying it because that is what I am looking for too.

vina1991 (author)RafaMemphis2016-05-02

Thank you for your positive feedback

It’s an automatic switching circuit that used to control an AC water pump. Operation of this circuit is simple.wen the water level goes below the limit the lower level sensor will detect it and activate the water pump.wen the water level reaches the upper limit the upper limit sensor detect it and switch of the water pump.

pmshah (author)vina19912016-05-05

This assumes that the water source is always available and will not allow a situation that can run the pump dry. I suggest you add an quad dual input nand gate IC, work out a karnaugh logic map that also takes into account the water levels in the source tank.

vina1991 (author)pmshah2016-05-07

I know.but my relay work as expected

vina1991 (author)pmshah2016-05-05

Thank You for Your Suggestion :)

i am happy to learn from error

SamW6 (author)vina19912016-05-06

Just use the relay in the normally closed position, not the normally open like the one in the schematic

vina1991 (author)SamW62016-05-06

Thanks for your spark

RafaMemphis (author)vina19912016-05-02

Hi vina1991,

I want my controller activate the water pump when the water reached in the upper sensor and switch off when the water drops to lower sensor.

akagrawal306 (author)RafaMemphis2016-05-05

so just assume the (high sensor) as low & (low sensor) as high as in this instructable, I mean Inverse.

[ ~~~~~~~~~~~~] -------------------------------------- “Low”

[~~~WATER~~~ ]

[ ~~ TANK ~~~~~]

[~~~~~~~~~~~~ ]

[~~~~~~~~~~~~ ]--------------------------------------- “High”

[______________]--------------------------------------- “MAIN”

This is the placing order of the sensors for yours type of case i think.

vina1991 (author)akagrawal3062016-05-05


if the HIGH prob is still immersed in water,when water touch the LOW prob there is no action

SamW6 (author)vina19912016-05-06

use the same circuit just with a relay in the normally closed connection

akagrawal306 (author)vina19912016-05-05

ops! I forgotten that! BTW very nice work! Keep it up Bro!

About This Instructable




Bio: a MAD man who fancies himself a genius
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