Spectroscopy#
Designing turbidimetry/nephelometry instrument
Many instrument design labs explore colorimetry or spectrophotometry, and the intention here is not to reinvent the wheel but to add to it. We will explore some aspects of instrument design such as signal amplification, non-chemical deviations from Beer’s Law, signal transduction and task-specific design.
Outcomes
A spectroscopic instrument that uses an LED as a source and detector
Circuit design for signal amplification, passive and active filtering
3D printing of a sample holder
Comparison of home-built vs commercial instrument performance
Exploring a relevant project idea.
Project timeline
Intro to turbidimetry/nephelometry - building an instrument that can measure the clarity of water
Watch intro videos and read paper
Setting goals for instrument design and introduction to CAD with OpenSCAD
Become familiar with OpenSCAD; develop idea for instrument
Download from their website
Which filter will be used (on board active does additional gain)
Source color (EPA uses White, we’ll use red or green)
Sample holder design
Phone wire for easy wiring
New circuit components: LEDs, transistors and filters
Do integrated simulation activities
Building the instrument
Solder instrument
Creating 3D printed prototypes of the instrument
3D printing
Create a device that can hold two LEDs at a fixed angle and incorporate the sample cell.
Modifying the prototype
3D printing
Measurements 1: Instrument setup
Measurements 2: Initial data acquisition
Measurements 3: Fixing mistakes, testing reproducibility and robustness
Presentation
http://www.mdpi.com/1424-8220/14/4/7142 might be interesting to model
Tip
See a problem? Have a suggestion? Please raise an issue and share your thoughts there.