Generally, data acquisition involves interfacing an analog sensor with a recording or display device to measure and record some value of interest over a period of time. For example, a meteorologist may want to measure and record the temperature during a 24-hour period. Sensors outputs are usually analog in nature, with voltage as the common output medium. The meteorologist's thermocouple, for example, may output 5.1 volts when the temperature is 70° F., and 5.4 volts when the temperature is 80° F. Before the advent of computers, this type of data was recorded continuously on a strip chart.
With the advent of low cost digital computers, almost all data storage is now done digitally. Typical commercially-available data acquisition systems sample the voltage signal from a sensor in discrete time intervals, e.g., once every minute. Generally, this analog voltage must be converted to a digital signal that the computer can process and store. This analog-to-digital conversion is typically done with specialized data acquisition hardware and software which must be installed in a user's computer. Generally, such data acquisition packages are expensive, timing consuming to install, require specialized knowledge to setup, and are not easily transferable from one computer to another.
What is needed, therefore, is a data acquisition system which is inexpensive, simple to setup and use, and easily transferable from one computer to another.