Water Level Indicator free essay sample

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. ere 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. We will write a custom essay sample on Water Level Indicator or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 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. hen 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(555tim er) 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. nd 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 water, instead of speaker we can use a automatic switch which can switch off the  pumping automatically. 4) COMPONENTS DESCRIPTION: A) IC 555 TIMER The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide up to four timing circuits in one package. Introduced in 1972 by Signetics, the 555 is still in widespread use, thanks to its ease of use, low price, and good stability. It is now made by many companies in the original bipolar and also in low-power CMOS types. As of 2003, it was estimated that 1 billion units are manufactured every year. ? PIN DIAGRAM: Pin 1 (Ground): Connects to the 0v power supply. Pin 2 (Trigger): Detects 1/3 of rail voltage to make output HIGH. Pin 2 has control over pin 6. If pin 2 is LOW, and pin 6 LOW,   output goes and stays HIGH. If pin 6 HIGH, and pin 2 goes LOW, output goes LOW while pin 2 LOW. This pin has a very high impedance (about 10M) and will trigger with about 1uA. Pin 3 (Output): (Pins 3 and 7 are in phase. ) Goes HIGH (about 2v less than rail) and LOW (about 0. 5v less than 0v) and will deliver up to 200mA. Pin 4 (Reset): Internally connected HIGH via 100k. Must be taken below 0. 8v to reset the chip. Pin 5 (Control): A voltage applied to this pin will vary the timing of the RC network (quite considerably). Pin 6 (Threshold): Detects 2/3 of rail voltage to make output LOW only if pin 2 is HIGH. This pin has a very high impedance (about 10M) and will trigger with about 0. uA. Pin 7 (Discharge): Goes LOW when pin 6 detects 2/3 rail voltage but pin 2 must be HIGH. If pin 2 is HIGH, pin 6 can be HIGH or LOW and pin 7 remains LOW. Goes OPEN (HIGH) and stays HIGH when pin 2 detects 1/3 rail voltage (even as a LOW pulse) when pin 6 is LOW. (Pins 7 and 3 are in phase. ) Pin 7 is equal to pin 3 but pin 7 does not go high it goes OPEN. But it goes LOW and will sink about 200mA. Pin 8 (Supply):Connects to the positive power supply (Vs). This can be any voltage between 4. 5V and 15V DC, but is commonly 5V DC when working with digital IC. INTERNAL BLOCK DIAGRAM: The LM555 is a highly stable controller capable of producing accurate timing pulses. With a mono stable operation, the time delay is controlled by one external resistor and one capacitor. This device features: Adjustable Duty Cycle, Turn off Time Less Than 2? Sec, Temperature Stability of 0. 005%/ °C, High Current Drive Capability (200mA) and Timing From ? Sec to Hours. The LM555 timer is applicable for Precision Timing, Time Delay Generation, Sequential Timing and Pulse Generation. The above schematic shows the LM555 Timer Internal Circuit Block Diagram. The Absolute Maximum Ratings (TA = 25 °C) of LM555 are as follows: |Parameter |Value | |Supply Voltage |16V | |Lead Temperature (Soldering 10sec)|300 °C | | |600mW | |Power Dissipation |(0 ~ +70) °C | |Operating Temperature Range |(-65 ~ +150) °C | |Storage Temperature Range | | | | | | | | | | | ? FEATURES: o High Current Drive Capability (200mA o Adjustable Duty Cycle o Temperature Stability of 0. 005%/ °C o Timing From  µSec to Hours o Turn off Time Less Than 2 µSec ? APPLICATION: o Precision Timing o Pulse Generation o Time Delay Generation o Sequential Timing B) BC 547 TRANSISTOR: [pic] |TECHNICAL SPECIFICATION: | |The BC547 transistor is an NPN Epitaxial Silicon Transistor. The BC547 transistor is a general-purpose transistor in a small| |plastic packages. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN | |general-purpose transistors. | |The BC547 transistor is an NPN bipolar transistor, in which the letters N and P refer to the majority charge carriers | |inside the different regions of the transistor. Most bipolar transistors used today are NPN, because electron mobility is | |higher than hole mobility in semiconductors, allowing greater currents and faster operation. NPN transistors consist of a | |layer of P-doped semiconductor (the base) between two N-doped layers. A small current entering the base in common-emitter | |mode is amplified in the collector output. In other terms, an NPN transistor is on when its base is pulled high relative | |to the emitter. The arrow in the NPN transistor symbol is on the emitter leg and points in the direction of the conventional| |current flow when the device is in forward active mode. One mnemonic device for identifying the symbol for the NPN | |transistor is not pointing in. An NPN transistor can be considered as two diodes with a shared anode region. In typical | |operation, the emitter base junction is forward biased and the base collector junction is reverse biased. In an NPN | |transistor, for example, when a positive voltage is applied to the base emitter junction, the equilibrium between thermally | |generated carriers and the repelling electric field of the depletion region becomes unbalanced, allowing thermally excited | |electrons to inject into the base region. These electrons wander (or diffuse) through the base from the region of high | |concentration near the emitter towards the region of low concentration near the collector. The electrons in the base are | |called minority carriers because the base is doped p-type which would make holes the majority carrier in the base | BC547 TRANSISTOR CIRCUIT SCHEMATIC SYMBOL | |[pic] | |BC547 TRANSISTOR PINOUTS | |[pic] | |BC547 TRANSISTOR SOURCES | |The BC547 is very common and manufactured by ON Semi, Fairchild, and NXP. They can be purchased in small quantity for $. 03 | |to $. 20 depending on variation Mouser, Digikey both stock the BC547 samples. | | | C) RESISTOR: | | [pic] | |A typical axial-lead resistor | [pic]A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistors terminals. This relationship is represented by Ohms law: [pic] where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conducto r in units of ohms. The ratio of the voltage applied across a resistors terminals to the intensity of current in the circuit is called its resistance, and this can be assumed to be a constant (independent of the voltage) for ordinary resistors working within their ratings. Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits, particularly analog devices, and can also be integrated into hybrid and printed circuits. D) CAPACITOR: A capacitor (originally known as condenser) is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric (insulator); for example, one common construction consists of metal foils separated by a thin layer of insulating film. Capacitors are widely used as parts of electrical circuits in many common electrical devices. When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them. Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes. The capacitor is a reasonably general model for electric fields within electric circuits. An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of charge  ±Q on each conductor to the voltage V between them: [pic] Sometimes charge build-up affects the capacitor mechanically, causing its capacitance to vary. In this case, capacitance is defined in terms of incremental changes: [pic] E) PRESET: A preset is a three legged electronic component which can be made to offer varying resistance in a circuit. The resistance is varied by adjusting the rotary control over it. The adjustment can be done by using a small screw driver or a similar tool. The resistance does not vary linearly but rather varies in exponential or logarithmic manner. Such variable resistors are commonly used for adjusting sensitivity along with a sensor. The variable resistance is obtained across the single terminal at front and one of the two other terminals. The two legs at back offer fixed resistance which is divided by the front leg. So whenever only the back terminals are used, a preset acts as a fixed resistor. Presets are specified by their fixed value resistance. Pin Diagram: F) BUZZER: A buzzer or beeper is an audio signalling device, which may be mechanical, electromechanical, or piezoelectric. Typical uses of buzzers and beepers include alarm devices, timers and confirmation of user input such as a mouse click or keystroke. Mechanical A joy buzzer is an example of a purely mechanical buzzer. Electromechanical Early devices were based on an electromechanical system identical to an electric bell without the metal gong. Similarly, a relay may be connected to interrupt its own actuating current, causing the contacts to buzz. Often these units were anchored to a wall or ceiling to use it as a sounding board. The word buzzer comes from the rasping noise that electromechanical buzzers made. Piezoelectric Piezoelectric disk beeper A piezoelectric element may be driven by an oscillating electronic circuit or other audio signal source, driven with a piezoelectric audio amplifier. Sounds commonly used to indicate that a button has been pressed are a click, a ring or a beep. G) PRINTED CIRCUIT BOARD: [pic] A printed circuit board, or  PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks, or  traces ,etched   from copper sheets laminated on to a non-conductive substrate. It is also referred to as printed wiring board(PWB) or  etched wiring board. A PCB populated with electronic components is a printed circuit assembly(PCA), also known as a printed circuit board assemble(PCBA). PCBs are inexpensive, and can be highly reliable. They require much more layout effort and higher initial cost than either  wire-wrapped or  Ã‚  point-to-point constructed   circuits, but are much cheaper and faster for high-volume production. Much of the electronics industrys PCB design, assembly, and quality control needs are set by standards that are published by the IPC organization. 5) SCOPE: This circuit only indicates the amount of water present in the over head tank, It gives an alarm when the tank is full. This worthy device starts ringing as soon as the water tank becomes full. It helps to check overflow and wastage of  water by warning the customer when the tank is about to brim. ? Now no need to go on the roof to look the water level. ? Alarm starts ringing as soon as tank becomes full. ? Suitable for every tank. ? Easy to make and economical circuit.