Iowa State University - ECpE Senior Design

Cost-Effective VIS-NIR Spectrometer Using a Linear CCD Sensor

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Project Overview

What We're Building

This senior design project focuses on designing, building, and validating a compact and affordable visible-near infrared VIS-NIR spectrometer capable of measuring spectral content of light across approximately 400 to 1000 nm.

The system is built around the TCD1304DG 3648 px linear CCD sensor for spectral detection, driven by an STM32 microcontroller for precise timing, signal acquisition, and data handling.

Conventional spectrometers are expensive and bulky. Our design emphasizes low cost, portability, modularity, and ease of use without sacrificing spectral performance, making it suitable for teaching labs and biomedical optics research alike.

Target Specifications

Wavelength Range 400 to 1000 nm
Spectral Resolution 1 to 5 nm
Detector TCD1304DG 3648 px
ADC Resolution 12 bit
Frame Rate 100 FPS
Interface USB / UART
Power Supply USB or Battery 5V / 3.3V
Real-World Application

Supporting BILabs Research

This spectrometer directly supports the photoacoustic imaging research conducted by Dr. Avishek Das at the Biomedical Imaging Laboratory. Photoacoustic imaging relies on delivering specific wavelengths of light into tissue.

By firing high-power LEDs and laser diodes at biological samples and reading the resulting fluorescence that emanates, researchers are able to map tissue structures.

Our device ensures these excitation sources emit exactly the expected spectral profile. Validating the emission wavelength and intensity is a mandatory step for accurate spectral unmixing. This exact measurement allows the research team to differentiate tissue types reliably and produce quantitative imaging data.

Technical Approach

System Architecture

The spectrometer integrates six key subsystems to deliver accurate, real-time spectral measurements in a portable form factor.

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Optical Subsystem

Entrance slit, collimating optics, diffraction grating, and focusing optics arranged to disperse incident light onto the linear CCD sensor.

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Analog Front-End

Custom Driver board which performs DC offset adjustment and low-pass filtering to condition the signal for the MCU, maximizing signal-to-noise ratio before ADC conversion.

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Embedded Firmware

STM32 firmware manages precise CCD timing using 3 hardware timers and DMA, ADC acquisition, data buffering, and host communication.

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PC Software Interface

Python based GUI for real-time spectral intensity visualization, data storage, and wavelength calibration workflows.

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PCB & Enclosure

Compact PCB using surface-mount components with careful grounding and noise mitigation. 3D-printed mechanical enclosure for portability.

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Wavelength Calibration

Calibration using narrow-line lasers or calibrated LEDs to map CCD pixels to wavelengths, validated against spectral accuracy targets.

Development

Source Code

All coding files, including the STM32 embedded firmware and the PC based graphical user interface code, are maintained on the Iowa State University GitLab server.

Visit GitLab Repository
Project Timeline

Expected Deliverables

The project spans two semesters progressing from design and prototyping to full integration and validation.

1

Semester 1: Spring 2026

  • Project scope and requirements definition
  • PCB schematic design and fabrication
  • CCD driver board assembly and testing
  • MCU development environment setup
  • Timer and ADC configuration
  • MCU and CCD integration
  • Optical component research and proposed layout
  • Desktop GUI development
2

Semester 2: Fall 2026

  • Optical component procurement and bench testing
  • Optical enclosure design and fabrication
  • Wavelength calibration and validation
  • Optics and hardware integration
  • Full system calibration and performance optimization
  • GUI optimization and feature completion
  • Mobile application architecture and UI development
  • Mobile and desktop integration with testing
Project Files

Semester 1 Documents

Access weekly progress reports and formal design documentation.

Weekly Reports

Design Documents

The Team

Meet the Engineers

A team of Electrical Engineering seniors from Iowa State University.

Samar Gill Headshot

Samar Gill

Electrical Engineering

Focusing on the optical subsystem. He leads the component selection and alignment to disperse light accurately onto the sensor.

Dawson Posekany Headshot

Dawson Posekany

Electrical Engineering

Has an emphasis in RF, antenna, and VLSI design. His focus in this project has been in the design and verification of the hardware and data transmission.

Ryan Majstorovic Headshot

Ryan Majstorovic

Electrical Engineering

Specializing in custom circuit design and software. He built the Python interface and handles the integration testing.

Evan Tamer Headshot

Evan Tamer

Electrical Engineering

Driving the system testing and validation. He verifies all operational parameters to guarantee the device meets the target specifications.

Faculty Advisor Manojit Pramanik - Iowa State University, ECpE Project Client Avishek Das - avishek@iastate.edu