SENSORS, DIGITAL INPUTS AND OUTPUTS
V. Ryan © 2002-04
Sensors are usually ‘analog’ devices. For example, a temperature sensor. This type of sensor usually ‘warms’ up slowly and cools down slowly. The change is constantly increasing or decreasing. A digital input or output is either ‘on’ or ‘off’. For example, a switch is either pressed or not pressed, an LED is either emitting light or not emitting light. (See previous notes on digital and analog signals). |
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The LED is a good example of a digital output because it is either ‘on’ or ‘off’ |
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THE USER ADAPTER The ‘user’ adaptor is plugged into the side of the smart
box. This device allows analog sensors, such as home-made sensors, to be
connected to the interface. |
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A HOME-MADE SENSOR
CONNECTED TO THE |
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HOME-MADE SENSORS A simple light sensor can be made from two components. The first is a light dependent resistor (LDR) and the second is a fixed resistor. When completed, it can be connected to the user adaptor and used as a proper sensor. A range of other sensors can be made in the same way. |
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Name some other sensors that
you think could be made in the workshop.
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