UV Sensor
Reports UV irradiance (W/m²) or UV-index value (0–11+) for one or more sub-bands by reading photocurrent from a UV-tuned photodiode through an integrating ADC, with on-chip cosine response correction.
A silicon (with UV-pass dye coating) or wide-bandgap (SiC, GaN) photodiode senses incident UV. Integrated optical filters narrow the response to UV-A (315–400 nm), UV-B (280–315 nm), or UV-C (100–280 nm) bands. A transimpedance amplifier converts photocurrent to voltage; a 16-bit ADC integrates over a configurable sampling window. On-chip lookup tables convert raw counts to calibrated UV-index values for consumer applications.
In plain terms
Like a sunburn-risk meter — invisible to the eye, but the chip turns the same UV that browns skin into a number you can read on a watch face.
Why designers use it
- Sunburn risk — wearable UV-A/B sensors warn users before sun damage occurs.
- Disinfection monitoring — UV-C dose tracking in hospital terminal-cleaning robots and water-treatment plants.
- UV-curing process control — semiconductor and printing applications need exposure-dose feedback.
- Solar weather — atmospheric ozone monitoring stations track stratospheric UV-B for long-term trend analysis.
Best for
- Wearables
- UV disinfection
- Industrial curing
Key specifications
- Operating limits: Check the exact manufacturer's datasheet (A family name does not establish voltage, current, temperature or timing limits.)
- Pin assignment: Match the complete part and package code (A similar name or function does not guarantee the same wiring.)
- Mechanical fit: Use the exact package drawing (Check pad layout, dimensions and viewing direction before building.)
When not to use it
- Where high-power UV-C measurement saturates silicon — pull SiC or GaN photodiodes for >100 mW/cm² UV-C.
- For full UV spectrum measurement — pull a spectrometer-grade UV detector, not a single-band sensor.
Common mistakes
- Mounting the chip behind plain plastic or glass — most plastics block UV-B, and the sensor reads zero indoors even on a sunny day.
- Forgetting the cosine correction — at high incidence angles, raw output reads low; pull a sensor with diffuser optics.
Where you will find it
- A Vishay VEML6075 UV-A/UV-B sensor in a Garmin Fenix 7 sport watch reads daily UV exposure: the chip's calibrated UV-index output drives sunburn-risk warnings during summer hikes, alerting the user before erythema risk crosses the threshold.
- A Dimer UVHero hospital robot uses a SiC GUVA-S12SD UV-C sensor to monitor disinfection dose during room terminal-cleaning: the chip reports cumulative J/cm² from the 254 nm UV-C lamps, ensuring each disinfection cycle reaches the 60 mJ/cm² SARS-CoV-2 inactivation dose.
- A NOAA atmospheric ozone monitoring station near Boulder, Colorado uses a Solar Light 501A UV-B radiometer with a SiC sensor element: the chip's ±5 % calibration to NIST-traceable standards supports long-term trend data for stratospheric ozone health.
A short history
A UV sensor typically functions as a photodiode: ultraviolet light striking it generates a small current roughly proportional to the UV radiation level. Because this current is very small, it is often fed into a transimpedance amplifier circuit, which converts the current into a voltage that a microcontroller's analog-to-digital converter can read and process.