{"title":"Adafruit LTR390 UV Light Sensor - STEMMA QT / Qwiic","handle":"adafruit-ltr390-uv-light-sensor-stemma-qt-qwiic","url":"/products/adafruit-ltr390-uv-light-sensor-stemma-qt-qwiic","description":"The Adafruit LTR390 is a dual-purpose UV and ambient light sensor with true UVA sensing at a peak spectral response between 300 and 350 nm. Unlike UV index approximation sensors, the LTR390 has a genuine UV photodiode — giving you real ultraviolet light measurements over a simple I2C interface.\n\nThe sensor also provides ambient light readings, making it useful for both UV exposure monitoring and general light level detection. The biasing and ADC are all internal, so no external components are needed. This STEMMA QT breakout includes voltage regulation and level shifting for both 3.3 V and 5 V systems.\n\nKey Features\n\n\nTrue UVA Sensing – Real UV photodiode with peak response at 300–350 nm\n\nAmbient Light Sensing – Dual-mode sensor for both UV and visible light measurements\n\nInternal ADC – No external analogue-to-digital converter required\n\nI2C Interface – Simple two-wire communication\n\nSTEMMA QT / Qwiic – Solderless I2C connectors for easy plug-and-play wiring\n\n3.3 V and 5 V Compatible – Onboard voltage regulator and level shifting\n\n\nIdeal For\n\nUV exposure monitoring and sun safety projects\nWeather stations with UV index estimation\nAmbient light sensing and display brightness control\nEnvironmental monitoring and wearable UV trackers\n\n\nPackage Contents\n\n1× Adafruit LTR390 UV Light Sensor Breakout (STEMMA QT)\n\n\n\nNote: This sensor provides raw UVA light readings, not a direct UV Index value. You can calculate an approximate UV Index from the raw data. STEMMA QT cable not included.\n\n\nResources\n\nWhat is STEMMA QT?\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":3564,"title":"Default Title","sku":"AF-4831","price":9.95,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":104,"option1":"Default Title"}]}