The necessary .ino file for a Genuino101 can you find inside of the apk file (open it with 7zip) in the assets folder.
The AS726x can detect 6 different colors/frequencies of light. It can be connected via I2C or serial to a Arduino or a Raspberry PI for spectroscopy.
In my case I used a Genuino101 and some hardware from Sparkfun:
Qwiic Shield for Arduino DEV-14352
Qwiic Cable - 50mm PRT-14426
Qwiic Cable - 500mm PRT-14429
Spectral Sensor Breakout - AS7262 Visible (Qwiic) SEN-14347
Spectral Sensor Breakout - AS7263 NIR (Qwiic) SEN-14351
At the moment it is only possible to connect one sensor at time, cause they have both the same I2C address. It is possible to use a muxer or the serial port if it is necessary to get data from both sensors.
With the inspiration from https://www.hackster.io/alexis-santiago-allende/arduino-101-ble-app-58aeb3 because of the BLE and MIT App Inventor part and https://github.com/sparkfun/Qwiic_Spectral_Sensor_AS726X how to get data from the sensor, I developed this little application to visualize the values as bargraph or curve and store the data (with a separate photo) as csv file in the mobile phone for later purpose.