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- The 555 Integrated Circuit (IC) is an easy to use timer that has many applications. It is widely used in electronic circuits and this popularity means it is also very cheap to purchase.
- A 'dual' version called the 556 is also available which includes two independent 555 ICs in one package.
1.Pin configuration
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 0.2uA.
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 ICs.
2. modes of operation
The 555 has three main operating modes, Monostable, Astable, and Bistable. Each mode represents a different type of circuit that has a particular output.
Astable mode
An Astable Circuit has no stable state - hence the name "astable". The output continually switches state between high and low without without any intervention from the user, called a 'square' wave. This type of circuit could be used to give a mechanism intermittent motion by switching a motor on and off at regular intervals. It can also be used to flash lamps and LEDs, and is useful as a 'clock' pulse for other digital ICs and circuits.
Monostable mode
A Monostable Circuit produces one pulse of a set length in response to a trigger input such as a push button. The output of the circuit stays in the low state until there is a trigger input, hence the name "monostable" meaning "one stable state". his type of circuit is ideal for use in a "push to operate" system for a model displayed at exhibitions. A visitor can push a button to start a model's mechanism moving, and the mechanism will automatically switch off after a set time.
Bistable Mode (or Schmitt Trigger)
A Bistable Mode or what is sometimes called a Schmitt Trigger, has two stable states, high and low. Taking the Trigger input low makes the output of the circuit go into the high state. Taking the Reset input low makes the output of the circuit go into the low state. This type of circuit is ideal for use in an automated model railway system where the train is required to run back and forth over the same piece of track. A push button (or reed switch with a magnet on the underside of the train) would be placed at each end of the track so that when one is hit by the train, it will either trigger or reset the bistable. The output of the 555 would control a DPDT relay which would be wired as a reversing switch to reverse the direction of current to the track, thereby reversing the direction of the train.
Astable mode
An Astable Circuit has no stable state - hence the name "astable". The output continually switches state between high and low without without any intervention from the user, called a 'square' wave. This type of circuit could be used to give a mechanism intermittent motion by switching a motor on and off at regular intervals. It can also be used to flash lamps and LEDs, and is useful as a 'clock' pulse for other digital ICs and circuits.
Monostable mode
A Monostable Circuit produces one pulse of a set length in response to a trigger input such as a push button. The output of the circuit stays in the low state until there is a trigger input, hence the name "monostable" meaning "one stable state". his type of circuit is ideal for use in a "push to operate" system for a model displayed at exhibitions. A visitor can push a button to start a model's mechanism moving, and the mechanism will automatically switch off after a set time.
Bistable Mode (or Schmitt Trigger)
A Bistable Mode or what is sometimes called a Schmitt Trigger, has two stable states, high and low. Taking the Trigger input low makes the output of the circuit go into the high state. Taking the Reset input low makes the output of the circuit go into the low state. This type of circuit is ideal for use in an automated model railway system where the train is required to run back and forth over the same piece of track. A push button (or reed switch with a magnet on the underside of the train) would be placed at each end of the track so that when one is hit by the train, it will either trigger or reset the bistable. The output of the 555 would control a DPDT relay which would be wired as a reversing switch to reverse the direction of current to the track, thereby reversing the direction of the train.
ABSTRACT
TITLE: Voice commanded calculator
first u need to know the difference between voice recognition & speech recognition
voice recognition:
speech recognition:
problems for using speech recognition:-
solution for certain limit: we can use WIFI shield or Zigbee or Bluetooth (any other related to this),even though it's not pc dependent but we can achieve wireless using the above modules for certain extents.
(it make project little expensive)
"" due the above problems i decided to use the voice recognition which is completely wireless and also PC independent ""
voice recognition:
- voice recognition is like a figure print
- it means it recognize only voice of particular person,
- for suppose the key word is "legendtronics",it will access only for a particular person whose voice is pre-stored
- this kind of recognition will be useful for a projects like door lock or any privacy ,secure related projects
speech recognition:
- it wants only the key word no necessarily the same person whose voice is pre-stored in the module. ,
- for suppose if the key word like"legendtronics" it will accepts the word irrespective of persons(not much accurately)
- voice recognition can be achieved using simple shield designed for arduino like Easy VR shield
- speech recognition can be achieved using the software like Matlab ,Bitvoicer......etc.
problems for using speech recognition:-
- it is PC dependent.
- wired
solution for certain limit: we can use WIFI shield or Zigbee or Bluetooth (any other related to this),even though it's not pc dependent but we can achieve wireless using the above modules for certain extents.
(it make project little expensive)
"" due the above problems i decided to use the voice recognition which is completely wireless and also PC independent ""
Hardware
required
·
Arduino
·
Easy VR shield
·
Micro phone
·
Display LCD,Speaker
·
Some other electronic stuff
Software required:
·
Arduino software
. Easy VR software
BLOCK DIAGRAM:
. Easy VR software
BLOCK DIAGRAM:
ELECTRONIC CIRCUIT LAYOUT:
VR shield is capable of storing 35 keywords,so it made our work simple& also convenient for our project
"zero to nine"...........................................10
"eleven to nineteen"....................................9
"ten ,twenty....to hundered".......................10
"thousand,lakh,crore".................................3
"plus,minus,multiply,divide,answer".............4
"sorry not recognised"................................1
"delete"......................................................1
"power off, power on"................................2
so if i want to calculate the result of 12005+546
i will utter "twelve" ,"thousand", "five ","plus" "five","hundred","forty","six"
how it will understand
...soon update........
why i have chosen VR shield for my project:-
VR shield not only serves to recognize the keyword but also used to be playback the voice through
8 ohms speaker which is attached to it ,when triggered.
so the answer can be uttered through the speaker from VR shield
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Further implementations:
·
Solar power
·
Adding the functions(trigonometry, matrices ……)
Its no more science fiction...it came into exist...we need to know how it rules our future & how it works????
million of answers available in internet for the question " how it works?"..
thousands of videos on YouTube demonstrates the wireless charging..
yet.....there is a question" how it actually works ?"
here we go...i will promise u ." u will learn at least 5 % on how it works and u will make u r own wireless charger for u r gadgets .."
1.what is wireless charging?
2. how it works?
Wireless charging, also known as inductive charging, is based on a few
simple principles. The technology requires two coils: a transmitter and a
receiver. An alternating current is passed through the transmitter
coil, generating a magnetic field. This in turn induces a voltage in the
receiver coil; this can be used to power a mobile device or charge a
battery.
- explanation with block diagram
both transmitter (TX) and receiver (Rx) coils are made up of copper coil.
rectifier is used to convert the ac signal to dc signals.
3. basic principle and it's efficiency factors:-
As i already told u ,the principle is mutual induction between the TX and receiver coil
let the induction of TX coil is L1 ,
inductance of RX coil is Rx,
distance between the coils are Z,
diameter of TX and RX coil be D1 and D2.
- the efficiency of the wireless power transmission depends on the 1, coupling factor
2, quality factor
The coupling is determined by the distance between the inductors (z) and the relative size (D2 /D1). The coupling is further determined by the shape of the coils and the angle between them
- The efficiency drops dramatically at larger distance (z/D > 1) or at a large size difference of the coil (D2/D1 < 0.3)
- A high efficiency (>90%) can be achieved at close distance (z/D < 0.1) and for coils of similar size (D2/D = 0.5..1)
B. QUALITY FACTOR:-
The ratio of the inductance L to the resistance R of a coil remains constant for different winding arrangements in the same volume and shape. It makes sense to define this value as a figure of merit to distinguish different coil structures. The quality factor Q is defined by this ratio.The voltage, which is induced by the same current in an inductor scales with the frequency f and thus the apparent power in the device.
The general definition of the quality factor is based on the ratio of apparent power to the power losses in a device
Remember quality factor is not under our control it is designed by the manufacturer
the value of quality factor will be 0 to infinity,For mass production you may expect values around 100
The power losses while transmission can be expressed as loss factor
which is the sum of all losses related to the transferred power. A deeper analysis results in an minimum loss factor, which can be achieved by a given wireless power system, if it is proper matched to load and generator:
Which can be reduced to:
The equation is only dependent on the two basic parameters of the wireless power system: The coupling factor k between the receiver and transmitter coil and the system quality factor Q. The system quality factor is the geometrical average of the transmitter’s and receiver’s quality factors.
BLAH BLAH BLAH......... there is no end to learning , it goes on...so stop it ..just apply the knowledge what u have learned so far....
6.how wireless better than wired????
4. calculation for getting max efficiency:-
The power losses while transmission can be expressed as loss factor
which is the sum of all losses related to the transferred power. A deeper analysis results in an minimum loss factor, which can be achieved by a given wireless power system, if it is proper matched to load and generator:
Which can be reduced to:
The equation is only dependent on the two basic parameters of the wireless power system: The coupling factor k between the receiver and transmitter coil and the system quality factor Q. The system quality factor is the geometrical average of the transmitter’s and receiver’s quality factors.
- This means, that the system quality factor and the coupling factor determine the performance in an equivalent way. A worse coupling can be linearly compensated by a better quality factor and vice versa.
BLAH BLAH BLAH......... there is no end to learning , it goes on...so stop it ..just apply the knowledge what u have learned so far....
5.circuit diagram:-
