The TSL2561 is bad for PAR measurement - too much error in yellow-red part - IR diode has significant response in this part of spectrum. The TSL34725 response looks like response of Apogee 2xx family - bad response in 400-420nm range. But grow light lacks of 420nm light - blue, white and red LEDs do...

PeteR_1, your builds are very nice! I perfer STM32 and do not use arduino; the latest STM32CubeIDE very easy to use and work out-of-the-box like arduino IDE, but much more powerful. My TCS34725 comparison with Apogee MQ-510: 630nm -1.5% 595nm 0 525nm +2% 490nm +5% 450nm 0 420nm -51% !!! UV cut filte...

PeteR_1, thanks for your feedback. The raw responses from TCS34725 and TCS34715FN for different wavelengths are very close: tcs34725_sensivity.png tcs34715fn_sensivity.png the difference is constant multiplier 1.7 The old versions of MultispeQ firmware (0_9) used Adafruit_TCS34725::calculateLux func...

I build my own PAR meter based on TCS34725 sensor: https://github.com/AVarfolomeev/tcs34725_par_meter2 https://raw.githubusercontent.com/AVarfolomeev/tcs34725_par_meter2/main/Documentation/Device.jpg I used clear acrylic resin, PLASTIK 71 PCB coating, to protect sensor PCB from water. I mean, the PA...