# \$1 AUTOMATIC WATER LEVEL CONTROLLER

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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

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

## Step 2: 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 relay.it can handle 7 Amp AC @240v.

## Step 3: 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

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

Runner Up in the
Sensors Contest 2016

## Recommendations

• ### Large Motors Class

12,253 Enrolled

## 185 Discussions

Wat was the logic needed to support underground sump tank, so that motor runs only when the water is sufficient.

I need to use a relay that draws more than 100ma. I assume that the BC547 transistor was chosen because of it's gain of 800, but it will not drive more than 100ma. I would normally substitute a 2N2222 in this instance because it will supply up to 800ma, but it only has a gain of 100. In this circuit, can 2N2222s be substituted for all 3 transistors and it still function properly (I assume that the bias resistors will have to have lower values)? If not, can a 2N2222 be substituted for just the relay driver? Thank you in advance.

I tried, but when only main and low that be under water the relay ia flickering. Why?

From where we can order some items \$1 AUTOMATIC WATER LEVEL CONTROLLER?

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?

2 replies

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

Would like to thank you for this useful simple project.

I made it on a breadboard and running for last 3/4 days without any problems. I have added 2 LED to indicate circuit is online + AC line ON/OFF with a 12v DC 1000mA power supply even you suggest not to add LED for circuit. what if I use a 1500mA power supply ? as you said LED itself takes 1A !

before I go for PCB layout I would like to see back side connection of your PCB as it looks very neatly assembled. Thanks for your time.

Hello, My Friend

i never said LED take 1A! I said "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."

Vina I tried your circuit very well and the relay also functioning. But what it happens if I try to connect all the connections in the water level the pump motor activates constantly. Couldn't get an ans can you help me.I think your ckt will be wrong or wrongly you posted

Hii vina how are you. you did this automatic water controller is awesome and i tried the same circuit but i didnt get an answer can you suggest any tricks you have done in this project

4 replies

you said that follow the circuit. In \$1 AUTOMATIC WATER LEVEL CONTROLLER there is having different circuit diagram. and ultra cheep home automation having different circuit diagram.

1. can you please say what circuit diagram you make the waterlevel controller.

2. how to use 12v dc relay with water level controller.

you said that follow the circuit. In \$1 AUTOMATIC WATER LEVEL CONTROLLER there is having different circuit diagram. and ultra cheep home automation having different circuit diagram.

1. can you please say what circuit diagram you make the waterlevel controller.

2. how to use 12v dc relay with water level controller.