This spectrophotometer project uses a diffraction grating to split white light into separate wavelengths. A mechanically actuated slit selects a single wavelength to pass through a sample and into a high-accuracy digital light sensor.


  • digital light sensor
  • diffraction grating
  • 1W white LED
  • 3V 500mA power supply (we use a 5V power supply with a large power resistor)
  • servo
  • magnifying glass
  • structural materials (LEGO blocks, cardboard, wood, or similar)
  • Arduino board
  • Grove sensor shield
  • sensor wires
  • additional wire

Optical Path

  • light source (LED)
  • lens (magnifying glass)
  • diffraction grating (at pivot point)
  • slit
  • sample
  • light sensor


In operation, the sensor and sample box should be cover to avoid measuring ambient light. This device requires manual (by-hand/by-eye) calibration.

Assembly instructions

Instructions will be provided when we have finished prototyping.