Water Level Indicator

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  • Topic: Bipolar junction transistor, Integrated circuit, Electronic component
  • Pages : 11 (2656 words )
  • Download(s) : 650
  • Published : May 16, 2013
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CONTENTS

1)INTRODUCTION

2)CIRCUIT DIAGRAM

3)HOW IT WORKS

4)COMPONENETS DESCRIPTION.

A. IC 555 TIMER

B. BC 547 TRANSISTOR

C. RESISTER

D. CAPACITOR

E. PRESET

F. BUZZER

G. PCB

5)SCOPE

1) INTRODUCTION:

Generally when we are pumping liquids like water or may be any other liquid is we need a human to see whether the tank is filled or not or we will place a overflow pipe to know that the tank is fill or not in case of water tank and we get confirmed from the water coming from overflow pipe that the has been filled. here is lots of wastage of water and still we need a human to have a look over it and so to avoid this and to save wastage of water or any other liquid that is being filled. Here is a simple circuit for liquid level alarm this circuit only tells us when the tank is full with a beep sound. It is built around two BC547 transistors (T1 and T2) and two timer 555 ICs(IC1 and IC2). Both IC1 and IC2 are wired in a stable multi vibrator mode. Timer IC1 produces low frequency, while timer IC2 produces high frequency. As a result, a beeping tone is generated when the liquid tank is full. Initially, when the tank is empty, transistor T1 does not conduct. Consequently, transistor T2 conducts and pin 4 of IC1 is low. This low voltage disables IC1 and it does not oscillate. The low output of IC1 disables IC2 and it does not oscillate. As a result, no sound is heard from the speaker. But when the tank gets filled up, transistor T1 conducts. Consequently, transistor T2 is cut off and pin 4 of IC1 becomes high. This high voltage enablesIC1 and it oscillates to produce low frequencies at pin 3. This low-frequency output enables IC2and it also oscillates to produce high frequencies. As a result, sound is produced from the speaker. Using preset VR1 we can control the volume of the sound from the speaker. The circuit can be powered from a 9V battery or from mains by using a 9V power adaptor. This circuit can be easily designed and it is easy to Assemble the circuit on a general purpose PCB and we can enclose it in a suitable cabinet. The circuit is as shown below. Circuit of water level indicator

 
2) CIRCUIT DIAGARM:

3) How it works:

The circuit contains
I. Bc547 transistors
II. Ic 555 timers
III. Resistors
IV. Capacitors
V. Speaker/Buzzer/alarm
VI. 9v power supply(battery/ 9v adaptor)
VII. Preset
VIII. PCB
Here we will install two water-level probes using metal strips such that one touches the bottom of the tank and the other touches the maximum level of the water in the tank. Interconnect the sensor and the circuit using a flexible wire as shown in above circuit diagram. when tank is empty or until the liquid touches the probe present at maximum level the transistor T1 doesn’t conducts and then output is high at collector of transistor T1, this drives the transistor T2 and transistor T2is in on state, and the output at collector of transistor will be low and as it is connected to pin4(reset pin) this disables ic1(555timer) and output at pin3 which is also low and as it is connected to pin4 of ic2(555timer) and the output is also low at pin3and it does not produce any sound .When the water or liquid level touches the second probe which is at maximum liquid level, the transistor T1 conducts and then output is low at collector of transistor T1, this drives the transistor T2 into cutoff and transistor T2 is in off state, and the output at collector of transistor will be high and as it is connected to pin4(reset pin) this enables ic1(555timer) and output at pin3 which is also high and as it is connected to pin4 of ic2(555timer) and the output is produced at pin3and it produces sound. and by hearing sound we can confirm that the tank is filled with liquid and we can stop filling it. Also we need a human to switch on and off the pumping of...
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