> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt # SI1145 Digital UV Index / IR / Visible Light Sensor **Type:** Product page · **SKU:** ADA1777 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia) **Page:** https://core-electronics.com.au/si1145-digital-uv-index-ir-visible-light-sensor.html ([markdown](https://core-electronics.com.au/si1145-digital-uv-index-ir-visible-light-sensor.html.md)) Remember when you were a kid and there was a birthday party at the pool and your parents totally embarrassed you by slathering you all over with sunscreen and you... ## Pricing - **Price:** $17.20 (inc GST) — $15.64 AUD, exc GST - **Quantity discounts:** 10+ $15.16 (exc GST) · 50+ $14.85 (exc GST) ## Availability & dispatch - Out of stock — the product page offers email notification when it returns. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=ADA1777:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/ADA1777:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description Remember when you were a kid and there was a birthday party at the pool and your parents totally embarrassed you by slathering you all over with sunscreen and you were all "MOM I HAVE ENOUGH SUNSCREEN" and she wouldn't listen? Well, if you had this UV Index sensor connected up to an Arduino you could have said "According to this calibrated SI1145 sensor from SiLabs, the UV index right now is 4.5 which means I do not need more sunscreen" and she would have been so impressed with your project that you could have spent more time splashing around. The SI1145 is a new sensor from SiLabs with a calibrated light sensing algorithm that can calculate UV Index. It doesn't contain an actual UV sensing element, instead it approximates it based on visible & IR light from the sun. Adafruit took this outside a couple days and compared the calculated UV index with the news-reported index and found it was very accurate! It's a digital sensor that works over I2C so just about any microcontroller can use it. The sensor also has individual visible and IR sensing elements so you can measure just about any kind of light - Adafruit only wrote Adafruit's library to printout the 'counts' rather than the calculate the exact values of IR and Visible light so if you need precision Lux measurement check out the TSL2561. If you're feeling really advanced, you can [connect up an IR LED](https://core-electronics.com.au/super-bright-5mm-ir-led-940nm.html) to the **LED** pin and use the basic proximity sensor capability that is in the SI1145 as well. Adafruit wrapped this nice little sensor up on a PCB with level shifting and regulation circuitry so you can safely use it with 3 or 5V microcontrollers. If you are using an Arduino, Adafruit have got a lovely tutorial and library already written up with example code so you can quickly read sensor readings and the UV index in under 10 minutes. Each order comes with one fully assembled and tested PCB breakout and a small piece of header. You'll need to solder the header onto the PCB but it's fairly easy and takes only a few minutes even for a beginner. ## Technical Details SI1145 Details: - [Datasheets, Fritzing objects, and EagleCAD PCB files available in the tutorial](https://learn.adafruit.com/adafruit-si1145-breakout-board-uv-ir-visible-sensor/downloads) - IR Sensor Spectrum: Wavelength: 550nm-1000nm (centered on 800) - Visible Light Sensor Spectrum: Wavelength: 400nm-800nm (centered on 530) - Voltage Supply: Power with 3-5VDC - Output Type: I2C address 0x60 (7-bit) - Operating Temperature: -40°C ~ 85°C Breakout Dimensions: - 20mm x 18mm x 2mm / 0.8" x 0.7" x 0.08" - Weight: 1.4g ![](https://core-electronics.com.au/attachments/localcontent/rohs_icon_8216055e11.jpg) ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/1/7/1777-00.jpg)