Lecturer

Md. Sadik Al Rayhan

Email : Sadik@ius.edu.bd

Educational qualification: 

Publications:

1. Visible Diffuse Reflectance Smartphone Spectrometer with High Spectral Accuracy
   
   Abstract: A smartphone-based spectrometer employing diffuse reflection principle is reported for the surface analysis of solid samples. The instrument utilizes a thin-film transmission grating for light diffraction and diffuse reflecting surface for projecting the image of the diffracted light onto the detector plane. The CMOS camera of smartphone camera directly captures the diffusely reflected photons within its limited field-of-view thus eliminating the need for collection, conditioning and converging optics. The optical setup of the instrument provides facility to calibrate the spectral response considering the nonlinear distribution of the wavelength across the diffraction direction. Additional correction in the detector response at different light intensity results a reduced spectral error with a maximum wavelength resolution of 𝛿𝜆 = 0.08 nm/pixel in the camera. This novel calibration method enables accurate spectral detection of narrowband molecular information within the spectral range Δλ = (400 – 700) nm of the instrument. As a proof of the concept, the instrument demonstrates successful detection of color pigments in food samples by absorption measurement of the samples at an average spectral error < 6%. The distinct absorption peak associated with standard food colors are compared against the absorption profile of unknown food colors used in pastry cake. This fieldfunctional smart analysis with internet connectivity opens opportunity of identifying food adulteration by using toxic chemical. Link
   
   
2. Smartphone Self-Contained NIR Colorimeter 
   
   Abstract: A self-contained smartphone based near infrared (NIR) colorimeter is reported for the first time by utilizing the inbuilt NIR emitter (𝛥𝜆 ≈ 770 − 1000nm) and macro-lens complementary metal-oxide semiconductor (CMOS) camera of phone. The emitted NIR light is guided through a low-cost multimode plastic fiber to illuminate the test sample and the phone’s CMOS camera is utilized to collect and digitize the transmitted light through that sample. An easy-to-use customized Android app has been developed to operate this ultra-lowcost (<$2) and field-portable (~174 gm) smartphone based NIR colorimeter fabricated by polyvinyl chloride (PVC) material. Performance of the instrument is evaluated by measuring the free fatty acid (FFA) percentage in the recycled palm oil samples with 0.21% average error of detection compared to the standard titration-based assessment. FFA is a significant quality indicator of vegetable oil, generally quantified in terms of oleic acid having an absorption peak at 𝜆𝑝 ≈ 930 nm which complies with the operating wavelength band (𝛥𝜆 ≈ 910 − 980 nm) of this instrument.

Projects:

• Speed Control of DC Motor Using H Bridge Converter for Automated Irrigation System. 
• Design and Development of a 45VA, 220/24V AC, 50Hz, Single phase Transformer. 
  
  
• Arduino-based Portable Pulse Oximeter for Real-time Health Monitoring.  
  
  
• Smart Traffic Control System Using Logic Gates.
  
  
  

Honors and Awards: 

• Technical scholarship throughout the 4 years study of B.Sc. Engineering from KUET (2019-2023). 
• Rajdhani Shikkha Foundation, Dhaka Scholarship 2014 
  
  
• Board of Intermediate and Secondary Education, Dhaka Scholarship -2013 
  
  
• The Students Welfare Foundation, Dhaka Scholarship 201 

Co-Curricular Activities:

• Awarded Gold Honor in the International Youth Math Challenge 2021 (Top 3% globally)
  
  
• Achieved Gold Honor in the International Youth Math Challenge 2019 (Top 2% globally).  
  
  
• Participated in a PCB Design Workshop, gaining hands-on experience in circuit design and layout.  
  
  
  

Extra-curricular Activities:

1. Member of Organizing Committee of KUET EEE DAY 2023 organized by Dept. of EEE, KUET 
   
   
2. Scouting: Participation in 13th Regional Scout Rally, 13th Metropolitan District Camp and sub-regional camp in Dhaka region.
   
   
3. Member of Notre Dame College Math Club.