Schematic designs and theoretical simulation to aid in building a self mixing optical interferometer. Theoretical explanation of pcb purpose and circuit part choices explained in this document (skip simulation details).

General idea is explained in the video. More in depth eplanation can be found at least in this publication.

Main motivation is to develope a convinient device toplay around with self mixing interferometry. It provides significant improvement in precision over ToF distance estimation (Arduino ToF sensor). Apart from using in objct distance and speed estimation it also can be usefull for harmonic motion measurements, e.g. submicron vibrations.

• Update current arduino shield to make convinient self-mxing laser interferometry easily accesible
  • Laser diode current modulation
    • (Optional) Reproduce convinient SPICE simulation from document (p. 34)
    • Prepare board for convinient pcb manufacturing Capacitors, resistors, leds are loosely defined. Missing voltage and maybe other parameters. Entries like ARDUINO_SHIELD or measuring points only add to the confusion.
      • EasyEda | LCSC
    • Optional: update KiCAD model
      • so that it visualizes electronic components in 3D
      • doesn't depend on deprecated symbols
    • Assess the modulation frequency of ADN8810
      • ~333 kHZ
    • Assess the probable performace of the board
      • Controlled by Arduino DUE (preferred)
        • What is maximum laser diode modulation frequencynoredirect=1#comment1266315_497173)
        • What is the maximum precision of modulated current
      • Controlled by STM32F4DISCOVERY
        • What is maximum laser diode modulation frequency
        • What is the maximum precision of modulated current
  • Physical printed and assemled board validation
    • Assemble board and connect to Arduino or arduino form factor development board
    • Write software to control PCB laser diode modulation
      • Code for modulatin ADN8810 from arduino
      • Arduino SPI Barometric Pressure Sensor
      • Some code
    • Verify laser diode modulation input
    • Verify laser monitor diode signal has interference pattern
  • Estimating values form monitor diode signal
    • Arduino ADC (current solution implemented on PCB) or FPGA
• Software for theoretical signal simulation and distance,velocity estimation
  • Python scripts for simulating and estimatimating values
    • Distance to stationary object
    • Distance and velocity of moving/stationary object
    • Velocity of moving object having noisy signal