personal light history

Version 1.0

The αΩ-meter records the personal spatial light history and allows for α-opic evaluation of arbitrary image regions.


The αΩ-meter is a camera based light dosimeter, that was developed as part of my PhD project. The αΩ-meter consist of a ESP32 microcontroller and an OmniVision OV2640 camera sensor with fish-eye lens. The dosimeter provides six channels. The five α-opic channels and a luminance channel:  sc, mc, lc, rh, mel and V(λ).


  1. ESP32-CAM Board
  2. OV2640 with 160° lens (diagonal)
  3. 2x 1.5 V AAA lithium battery
  4. AAA battery clip
  5. 2x short wires
  6. Micro SD-card
  7. Housing (3D model available)
  8. USB-TTL adapter (firmware & calibration)
  9. Jumper wires female-female (firmware & calibration)

Flash the firmware:

To flash the firmware onto the ESP32-CAM board, follow these steps:

  1. Setup the flash toolchain ESP-IDF (eclipse recommended)
  2. Connect the USB-TTL adapter to the ESP32-CAM board
  3. Compile the firmware
  4. Flash the firmware


  1. Glue the battery clip into the case.
  2. Flash the firmware onto the ESP32-CAM board.
  3. Solder the two wires to the battery clip and the ESP32.CAM board, +3V and ground.
  4. Format SD-card with FAT32 format.
  5. Create the folders “calibration” and “data” on the SD card.
  6. Create settings file and add it to the “calibration” folder.
  7. Insert SD-card.
  8. Connect camera to ESP32CAM board.
  9. Insert 2x 1.5 AAA lithium batteries.
  10. Close the dosimeter case.


The calibration process is divided into several stages. For each step, Matlab and Octave scripts or prepared calibration files will be available after the PhD thesis publication.