10-03-2011, 10:56 AM
PRESENTED BY
K.RAJEEVI PRIYANKA
K.SWETHA BHAVANI
G.SWATHI MALLIKA
U.MAHESH
weatherforcost ppt.ppt (Size: 474 KB / Downloads: 123)
WEATHER FORECASTING
ABSTRACT
• Here is an automated system being designed to get the weather forecast report in day to day life.
• This system is designed around a microcontroller which forms the control unit of the project.
• According to this system, different parameters such as temperature, humidity are being sensed and are being displayed in LCD.
TEMPERATUR SENSOR (THERMISTOR):
• The word thermistor is an acronym for thermal resistor, i.e., a temperature sensitive resistor.
• It is used to detect very small changes in temperature.
• Thermistors with both negative-temperature-coefficients (NTC) and positive temperature coefficient (PTC) are available.
• Thermistors are manufactured in the form of beads, probes, disc, washers and rods.
• The beads are made in diameter ranging from 0.15mto 2.5mm
ADC MODULE
An ADC is a device that converts a continuous analog signal to a multi-level digital signal without altering its content.
The signals that are monitored are sounds, movement, and temperature into Binary code for the PC.
Parallel converter (Flash ADC)
• Fastest
• High Resolution
• Converter Requires (2^n -1) Comparators
Successive Approximation type
• A sample and hold circuit to acquire the input voltage (Vin).
• An analog voltage comparator that compares Vin to the output of the internal DAC and outputs the result of the comparison to the successive approximation register (SAR).
• A successive approximation register sub circuit designed to supply an approximate digital code of Vin to the internal DAC.
• An internal reference DAC that supplies the comparator with an analog voltage equivalent of the digital code output of the SAR for comparison with Vin.
Counter Type ADC
• Simplest Type Of ADC
• A control logic is used to open agate for starting a counter the counter pulses are fed to the DAC .
• Output of the DAC is compared continually with the analog input.
Integrating ADC
• An integrating ADC is a type of analog-to-digital converter that converts an unknown input voltage into a digital representation through the use of an integrator.
• Converters of this type (or variations on the concept) are able to achieve high resolutions
• Their use is typically limited to digital voltmeters and other instruments requiring highly accurate measurements.
• Process is slow typically 300ms are required to perform a conversion.
Applications of ADC:
Digital camera
Scanners
Cell phone
Digital desk phone
BUZZER
• The "Piezoelectric sound components" introduced herein operate on an innovative principle utilizing natural oscillation of piezoelectric ceramics.
• These buzzers are offered in lightweight compact sizes from the smallest diameter of 12mm to large Piezo electric sounders.