Distance sensor

From ArticleWorld

The distance sensor is a device used in automobiles in order to facilitate the measurement of the distance travelled. Each time the transmission of the vehicle rotates a series of electrical pulses is generated by the distance sensor. These pulses are then used to calculate the distance travelled by the vehicle. The information in the form of pulses can also be used to indicate not just the distance moved, as in an odometer, but also for the indication of speed, as in a speedometer. The distance information is particularly useful for calculating taxicab fares using taximeters, which consider not just the distance travelled but also the time spent in waiting.The three indicating devices that use distance sensors are commonly used in digital form.

• The speedometer:

The speedometer involves the selection of a sample point of the transmission. A distance sensor is installed here in order to translate mechanical rotations of the transmission shaft into electronic pulses. A microprocessor is used for converting the interval between successive pulses into a digital output, which can be displayed for the driver to see.

• The odometer:

As described above, a microprocessor is used to create digital equivalents of the intervals between successive pulses. The pulses themselves are also counted by the microprocessor in order to calculate the reading of the distance travelled and display it on the odometer. Both the speedometer and the odometer have to be appropriately calibrated.

• The taximeter:

Taximeters are used for calculating fares based on the distance travelled by the taxi and the time for which the taxi has waited. Thus it essentially consists of an odometer which is calibrated according to the existing fares. Fare is considered for the waiting time as well, with pulses being counted after every set interval when the taxi is stationary.