PC Based data acquisition system
PC Based data acquisition system by stimulating SPI and I2C protocol
Many times it is required to monitor physical phenomena such as temperature, pressure humidity, light intensity, sound intensity, force, etc. Such physical phenomena can be monitored by digital systems employing sensors. However sensor generally produces a change in the resistance, voltage or current. All such phenomena can be converted in to a change in voltage levels. Since the sensors and the subsequent signal conditioning circuits provide a proportionate change in voltage with respective the phenomena, this cannot be directly interpreted by a digital system. A sensor is ussaually an analog voltage and can take any value between +10 to -10 volts. However a digital system has only two states (ON) or (OFF). Thus it is required to have additional circuitry between the digital systems and analog systems that translate the analog signals in to a digital signals. Such conversion can be perform by an analog to digital converter.
The Serial Peripheral interface Bus or SPI (often pronounced “spy”) bus Is a synchronous serial data link standard that operates in full duplex mode. Devices communicate in master/slave mode where the master device initiates the data frame. Multiple slave devices are allowed with individual slave select (chip select) lines. The I2C bus physically consists of two active wires and a ground connection. The active wires called SDA and SCL, are both bi-directional. SDA is a serial data line, SCL is a serial clock line.
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Many times it is required to monitor physical phenomena such as temperature, pressure humidity, light intensity, sound intensity, force, etc. Such physical phenomena can be monitored by digital systems employing sensors. However sensor generally produces a change in the resistance, voltage or current. All such phenomena can be converted in to a change in voltage levels. Since the sensors and the subsequent signal conditioning circuits provide a proportionate change in voltage with respective the phenomena, this cannot be directly interpreted by a digital system. A sensor is ussaually an analog voltage and can take any value between +10 to -10 volts. However a digital system has only two states (ON) or (OFF). Thus it is required to have additional circuitry between the digital systems and analog systems that translate the analog signals in to a digital signals. Such conversion can be perform by an analog to digital converter.
The Serial Peripheral interface Bus or SPI (often pronounced “spy”) bus Is a synchronous serial data link standard that operates in full duplex mode. Devices communicate in master/slave mode where the master device initiates the data frame. Multiple slave devices are allowed with individual slave select (chip select) lines. The I2C bus physically consists of two active wires and a ground connection. The active wires called SDA and SCL, are both bi-directional. SDA is a serial data line, SCL is a serial clock line.
contd....
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