Advanced Adventures in Science Under the Supervision of.pdf

1Calibration of an Optical Sensor Jimmy H. Daruwalla Sidwell Friends School Advanced Adventures in Science Under the Supervision of Dr. Nicholas G. Dagalakis Intelligent Systems Division National Institute of Standards and Technology March 9th, 2001 Abstract An inexpensive optical reflective sensor was evaluated for possible use as a precision proximity sensor. The output signal of the sensor was measured as a function of the distance of a flat reflecting surface from the front glass window of the sensor. The experimental data support the hypothesis that the sensor may be used as a precision proximity sensor. Key words: proximity sensor, precision sensor, inexpensive sensor, optical sensor Introduction Proximity sensors have been used to determine distances between two objects. During everyday technological experiments in precision engineering, a need for an inexpensive but accurate proximity sensor has arisen. I have tested to see if an inexpensive sensor currently used for scanning barcodes will be able to stand up to the needs of precision engineers today. This idea was first proposed by Dr. Lowell Howard, when he was still working for the Precision Engineering Division (PED) of the National Institute of Standards and Technology (NIST). Dr. Howard also built the sensor signal conditioning electronics used in my experiment. Hypothesis The 655 nm Precision Optical Reflective Sensor manufactured by Agilent Technologies [1] under the trade name HEDS-15001 can be used for precision proximity sensing. 1 HEDS-1500 is a trademark of Agilent Technologies. This and certain commercial products are identified in this paper to specify experimental procedures adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the products identified are necessarily the best available for the purpose. 2Figure 2. HEDS-1