Introduction
Spectrophotometers are instrumental in our project, enabling us to analyze optical properties and measure substance concentrations, serving crucial functions such as conducting tests for decolorization efficiency and assessing the degree of color change in ABTS assays.However, these conventional devices often come with a hefty price tag and are not always accessible, especially for researchers and educators operating on a shoestring budget or in environments where professional equipment is scarce. Our objective, therefore, is to devise an affordable, simple-to-assemble spectrophotometer that not only meets experimental demands but also doubles as an educational tool.
Version 1: An Initial Step Towards Affordable Spectrophotometry
In our preliminary design, we aimed to develop a low-cost spectrophotometer that could fulfill experimental requirements and serve educational purposes. The core components of Version 1 included an LED light source, a photoresistor as a detector, Arduino Uno as a control board, an LCD 1602C for display, and a customized cuvette slot created through 3D printing. This version was capable of measuring sample absorbance by reading the photoresistor's value, processing it through the Arduino, and displaying results on the LCD. Powering this device was versatile, utilizing PCs, power banks, and USB adapters via the Arduino Uno's USB interface.
Figure 1: Version 1 - Preliminary Hardware Setup Prior to Enclosure within the Cardboard Box
Cost Analysis - Version 1
Total Cost: €13.99 / $14.83
Figure 2: Cost Estimation for Version 1
Version 2: Enhancing Accuracy with Specific Wavelength Detection
The upgraded design of Version 2 significantly enhances the instrument's accuracy and functionality,
while also facilitating interaction with external software. A key improvement in this version is the
integration of an RGB LED light source. This RGB LED is specifically chosen for its ability to emit
light at distinct wavelengths (Red: 620-625nm, Green: 520-525nm, Blue: 460-465nm), closely matching
the absorption peaks of many samples. This precise alignment with the absorption peaks ensures more
accurate and sensitive measurements compared to the previous LED wavelengths.
In addition to the RGB LED light source, Version 2 includes a BH1750 module for improved light
detection, and an ESP32 control board, which introduces WiFi and Bluetooth capabilities. This allows
for seamless data transfer and remote operation. We've also implemented new operational features,
such as 'blank' and 'test' buttons, enhancing the instrument's range of applications. Lastly, the
cuvette slot has been redesigned for better compatibility with these new components, ensuring a more
efficient and user-friendly experience for diverse analytical needs.
Figure 3: Version 2 - Enhanced Hardware Assembly Before Installation in the Cardboard Box
Cost Analysis - Version 2
Total Cost: €13.33 / $14.09
Figure 4: Financial Breakdown for Version 2
