Sensors & Circuits: Difference between revisions

Revision as of 15:24, 27 June 2007

Hall Effect

Hall Effect on Sensorwiki.org

IR Distance

Reflective Optical Sensor

The reflective optical sensor ( Datasheet ) consists of an infrared LED, labelled "E" for Emitter on the diagrand and on the package, and a phototransistor that passes an amount of current proportional to the reflected light received. The phototransistor is labelled "S" for Sensor. The one leg of the sensor is connected to +5V, which supplies current, and the voltage drop across the 10k resistor that we measure is proportional to the amount of current.

There is a continuous voltage response for objects over a short range of proximity to the sensor. The response is not linear. Linearity can be approximated by the log of the log of the signal.

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-==Piezo Pickups==
-==Rotary Encoders==
-<center>
-[[Image:quadrature.png]]
-</center>
-The above diagram demonstrates two signals in a quadrature relationship as the signals from the two lines of the rotary encoders are. Note that Phase A leads Phase B by 90 degrees when looking from left to right. Looking from right to left the opposite is true. This is directly analogous to the change in signal relationship when the rotary encoder is turned the opposite direction.
-<center>
-[[Image:encoder_filter.png]]
-</center>
-This filter circuit helps to stabilize the output of the shaft encoder and reduces noise by introducing pull-up resistors and low pass filters with cut-off frequency of ~ 1.6kHz on each of the two output pins.
 ==Hall Effect==
 [http://www.sensorwiki.org/index.php/Hall_effect Hall Effect] on Sensorwiki.org
-==Mulitplexing==
 ==IR Distance==
-===Sharp===
 ===Reflective Optical Sensor===