You can build an OLED display onto an Arduino Nano with a TSL2591 spectroscopic sensor (well, two channels - visual and NIR ...) by combining sketch examples online. What you get is a 4-line display of total flux, visual flux, NIR, and an index called the NDVI index.
First install some libraries:
Step 1: Fixing Setup of the Adafruit_SSD1306.h File
The file "Adafruit_SSD1306.h" may be set for a 128x32-pixel display. If you have the 128x64 display you will want to edit near lines 73-75 of the file. Comment out the _16 and _32 lines and UNcomment the _64 line. It should look like the picture.
Step 2: Wiring the Arduino Nano, the TSL2591 and the SSD1306 OLED Display.
I am reusing a Nano - hence the header pins ...
Power over USB-mini - code also provides Serial port output that can be read externally and logged, if you like.
Step 3: My Code
Get the code and upload to the board. Output will be on the OLED screen, as well as over the serial port - Full, Visual, IR, and the NDVI.