Sensors & transducers


AnAlog Devices’ BAoxing chen nAmeD ieee Fellow


Figure 11. Chlorophyll samples made with spinach. RMS Noise Value (% Spinach)


Table 5. Fluorescence MeasureMenT noise Value 7.5% Spinach Sample 0.0616


setup equipment CN0503 evaluation board EVAL-ADICUP3029 evaluation board Spinach solution For this experiment, a spinach solution was


created by blending spinach leaves with water. This was then filtered and kept as the stock solution. The stock solution was then diluted to result in samples of different percent spinach solution. These were used as standards to create a curve of percent spinach solution through fluorescence. Optical path 1 was used along with the 365 nm LED card and the long-pass filter inserted.


20% Spinach Sample 0.1158


To get the noise value, two different


data points were picked: one near the bottom of the range and one near the top because the curve fit was not linear. The noise is given by the standard deviation of a set of repeated measurements for each point, as shown in Table 5. To determine the LOD, the noise value is


measured for a blank or low concentration sample, then multiplied by three to represent a 99.7 per cent confidence interval.


Table 6. Fluorescence MeasureMenT liMiT oF DeTecTion


Blank Sample


Limit of Detection (% Spinach) 0.1621


Figure 12. Calibration curve for per cent spinach solution.


results The calibration curve for per cent spinach solution is shown in Figure 12. The trendline equation for this calibration curve


can be stored so that the results are directly reported as a percentage by the CN0503.


Instrumentation Monthly February 2022


conclusion Prototyping complex optical liquid analysis measurements is a challenge that requires careful consideration of how chemistry, optics, and electronics interact to produce a precise result. Integrated AFE products like the ADPD4101 pave the way for higher performance optical liquid sensing in smaller spaces. The CN0503 builds on the ADPD4101, including optical design, firmware, and software for an easy to use and highly customisable rapid prototyping platform that is capable of taking accurate optical measurements of liquid parameters, including absorbance, colorimetry, turbidity, and fluorescence.


Analog Devices www.analog.com


integrated signal-power isolation and integrated magnetics. IEEE Fellow is the highest grade of IEEE membership and is recognised by the technical community as a prestigious honour and an important career achievement. The total number selected in any one year cannot exceed one-tenth of one- percent of the total voting membership. “I am incredibly humbled and honoured to


A


be named an IEEE Fellow,” says Dr. Chen. “This is a testament to Analog Devices’ leadership in digital isolation technology, which is only made possible through decades of dedication from our isolation team. I am extremely fortunate to work in such a collaborative environment where innovation is nurtured and valued.” Dr. Chen, who joined Analog Devices in


1997, was named an ADI Fellow in 2010. As the chief technologist for the Isolation Group, he pioneered iCoupler and isoPower digital isolation technology from inception through today’s innovations, enabling over 4.4 billion isolation channels shipped. He also heads chip scale thermoelectric harvester developments at ADI. Dr. Chen has published more than 40 papers and holds 52 US patents. Additionally, he is an adjunct professor in Northeastern University’s Electrical and Computer Engineering Department and also serves as associate editor for IEEE Transactions on Power Electronics. Dr. Chen holds a Ph.D. in Physics and a M.S. in Electrical Engineering from the University of Michigan as well as a B. S. in Physics from Nanjing University in China. The IEEE is the world’s leading professional


association for advancing technology for humanity. Through its 400,000 plus members in 160 countries, the association is a leading authority on a wide variety of areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power, and consumer electronics.


Analog Devices www.analog.com


47


nalog Devices’ Technology Fellow Dr. Baoxing Chen has been named a 2022 IEEE Fellow for his contributions to


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