# Adafruit LTR-329 and LTR-303 Light Sensors ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/115/238/medium800thumb/light_LTR-329_demo.jpg?1663621644) The  **Adafruit LTR-329 and LTR-303 Light Sensors** are simple and popular low-cost I2C digital light sensors that are easy to integrate into your project for reliable and wide-ranging light measurements. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/229/medium800/light_LTR-303_top_angle.jpg?1663619693) Perfect for a wide range of project use cases: Should we turn up the brightness of our display or dim it to save power? Which direction should your robot move to stay in an area with the most light? Is it day or night? All of these questions can be answered with the help of these sensors. They're small, capable and inexpensive light sensors that you can include in your next project to add the detection and measurement of light. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/230/medium800/light_LTR-329_top.jpg?1663619703) The LTR-329 and LTR-303 provide 16-bit light measurements for both Infrared and Visible+IR spectrums. Subtract one from the other to get human-visible light. Thanks to configurable gain and integration time settings, both sensors can measure from 0 to 65K+ lux. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/231/medium800/light_LTR-303_top_header.jpg?1663619730) The 303 (compared to the '329) also comes with alert and IRQ capabilities so you can have a pin trigger when the reading goes above or below threshold values. Great if you want ultra-low power usage. If you _don't_ need a version with interrupt output, check out the Adafruit LTR-329 which is basically the same sensor but without the IRQ capability. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/234/medium800/light_LTR-329_top_angle.jpg?1663619870) Sensors tend to come in small packages and the LTR-329 and LTR-303 are no different. Not much bigger than a grain of rice, these handy light-sensing friends need some help to be used by folks experimenting and without the desire or tools to work with surface mount parts. We're here to help! ![](https://cdn-learn.adafruit.com/assets/assets/000/115/235/medium800/light_LTR-303_back.jpg?1663619893) Packaged on a PCB in our  **STEMMA QT** form factor, these sensors come integrated with a voltage regulator and level shifting circuitry to allow them to be used with 3.3V devices, like a ** Feather M4**  or  **Raspberry Pi** , or  **5V**  devices, such as an  **Arduino**. Rather than working with the itty bitty little contacts on the sensor, the PCB it's packaged on breaks out all the pins to a standard 0.1" / 2.54mm pitch header. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/232/medium800/light_LTR-329_STEMMA_side.jpg?1663619763) To make things easier and a bit more flexible, we've also included ;[SparkFun Qwiic](https://www.sparkfun.com/qwiic) compatible [STEMMA QT](https://learn.adafruit.com/introducing-adafruit-stemma-qt) connectors for the I2C bus so you don't even need to solder! Just plug in a compatible cable and attach it to your MCU of choice, and you’re ready to load up some software and measure some light. [**QT Cable is not included** , but we have a variety in the shop](https://www.adafruit.com/?q=stemma+qt+cable&sort=BestMatch). ![](https://cdn-learn.adafruit.com/assets/assets/000/115/236/medium800/light_LTR-329_back.jpg?1663619917) [To help with the software part we’ve written a library that you can use with **CircuitPython** / Python devices as well as computers like the Raspberry Pi by installing it using PyPi](https://github.com/adafruit/Adafruit_CircuitPython_LTR329_LTR303). You can even use it on a full-sized computer by using an [MCP2221 breakout](https://www.adafruit.com/product/4471). **Arduino** users can use our [LTR-303 Arduino library with lots of examples](https://github.com/adafruit/Adafruit_LTR329_LTR303) to get started fast. # Adafruit LTR-329 and LTR-303 Light Sensors ## Pinouts ![](https://cdn-learn.adafruit.com/assets/assets/000/115/272/medium800/light_LTR-329_and_303.jpg?1663706641) Info: ## Power Pins - **VIN** - This is the power pin. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V microcontroller like Arduino, use 5V. - **3V ** - This is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like. - **GND** - This is the common ground for power and logic. ## I2C Logic Pins The I2C address is **0x29**. - **SCL** - I2C clock pin, connect to your microcontroller I2C clock line. This pin is level shifted so you can use 3-5V logic, and there's a **10K pullup** on this pin. - **SDA** - I2C data pin, connect to your microcontroller I2C data line. This pin is level shifted so you can use 3-5V logic, and there's a **10K pullup** on this pin. - [**STEMMA QT**](https://learn.adafruit.com/introducing-adafruit-stemma-qt) ** -** These connectors allow you to connectors to dev boards with  **STEMMA QT** connectors or to other things with [various associated accessories](https://www.adafruit.com/?q=JST%20SH%204). ## On LED and LED Jumper - **on LED** - On the front of the breakout, right above the STEMMA QT connector on the left, is the on LED. It is labeled **on** on the silk. This green LED lights up when the board is powered. ![](https://cdn-learn.adafruit.com/assets/assets/000/115/466/medium800/light_LTR-303_LTR-329_back_pinouts.jpg?1664391094) - **LED jumper** - On the back of the board is a jumper labeled **LED**. To disable the on LED, cut the trace between the two pads. To enable it again, bridge the two pads together with solder. ## LTR-303 Interrupt Pin - **INT** - This is the interrupt pin, available only on the LTR-303. The alert and IRQ capabilities enable you to have a pin trigger when the reading goes above or below threshold values. # Adafruit LTR-329 and LTR-303 Light Sensors ## Python & CircuitPython It's easy to use the **LTR-329 ** and the  **LTR-303** with Python or CircuitPython, and the [Adafruit\_CircuitPython\_LTR329\_LTR303](https://github.com/adafruit/Adafruit_CircuitPython_LTR329_LTR303) module. This module allows you to easily write Python code that reads the values from the **LTR-329** and **LTR-303**  light sensors. You can use this sensor with any CircuitPython microcontroller board or with a computer that has GPIO and Python [thanks to Adafruit\_Blinka, our CircuitPython-for-Python compatibility library](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux). This page focuses heavily on the LTR-329, but using the LTR-303 is basically the same. At the end of the page you'll find an LTR-303-specific example utilizing the **int** pin. ## CircuitPython Microcontroller Wiring Info: Wire up an LTR-329 to your board exactly as shown below. Here's an example of wiring a Feather RP2040 to the sensor with I2C using one of the handy [**STEMMA QT**](https://learn.adafruit.com/introducing-adafruit-stemma-qt) connectors: - **Board 3V**  to **sensor VIN (red wire)** - **Board GND**  to  **sensor****  GND (black wire)** - **Board SCL**  to  **sensor****  SCL (yellow wire)** - **Board SDA**  to  **sensor****  SDA (blue wire)** ![light_LTR-329_Feather_STEMMA_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/050/medium640/light_LTR-329_Feather_STEMMA_bb.jpg?1666303615) You can also connect the LTR-329 using standard **0.1" pitch**  headers to wire it up on a breadboard: - **Board 3V**  to **sensor VIN (red wire)** - **Board GND**  to  **sensor****  GND (black wire)** - **Board SCL**  to  **sensor****  SCL (yellow wire)** - **Board SDA**  to  **sensor****  SDA (blue wire)** ![light_LTR-329_Feather_breadboard_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/051/medium640/light_LTR-329_Feather_breadboard_bb.jpg?1666303649) ## Python Computer Wiring Since there's _dozens_ of Linux computers/boards you can use, below shows wiring for Raspberry Pi. For other platforms, [please visit the guide for CircuitPython on Linux to see whether your platform is supported](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux).  Here's the Raspberry Pi wired to the LTR-329 using I2C and a [**STEMMA QT**](https://learn.adafruit.com/introducing-adafruit-stemma-qt) connector: - **Pi 3V**  to  **sensor****  VIN (red wire)** - **Pi GND**  to  **sensor****  GND (black wire)** - **Pi SCL**  to  **sensor****  SCL (yellow wire)** - **Pi SDA**  to  **sensor****  SDA (blue wire)** ![light_LTR-329_RasPi_STEMMA_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/053/medium640/light_LTR-329_RasPi_STEMMA_bb.jpg?1666303702) Here is the Raspberry Pi wired to the LTR-329 using a solderless breadboard: - **Pi 3V**  to  **sensor****  VIN (red wire)** - **Pi GND**  to  **sensor****  GND (black wire)** - **Pi SCL**  to  **sensor****  SCL (yellow wire)** - **Pi SDA**  to  **sensor****  SDA (blue wire)** ![light_LTR-329_RasPi_breadboard_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/054/medium640/light_LTR-329_RasPi_breadboard_bb.jpg?1666303742) ## Python Installation of LTR329\_LTR303 Library You'll need to install the  **Adafruit\_Blinka**  library that provides the CircuitPython support in Python. This may also require enabling I2C on your platform and verifying you are running Python 3. [Since each platform is a little different, and Linux changes often, please visit the CircuitPython on Linux guide to get your computer ready](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux)! Once that's done, from your command line run the following command: - `pip3 install adafruit-circuitpython-ltr329-ltr303` If your default Python is version 3, you may need to run `pip` instead. Make sure you aren't trying to use CircuitPython on Python 2.x, it isn't supported! ## CircuitPython Usage To use with CircuitPython, you need to first install the LTR329\_LTR303 library, and its dependencies, into the  **lib**  folder on your  **CIRCUITPY**  drive. Then you need to update  **code.py**  with the example script. Thankfully, we can do this in one go. In the example below, click the  **Download Project Bundle**  button below to download the necessary libraries and the  **code.py**  file in a zip file. Extract the contents of the zip file, and copy the  **entire **** lib ** ** folder ** and the ** code.py ** file to your ** CIRCUITPY** drive. Your  **CIRCUITPY/lib**  folder should contain the following folders and file: - **adafruit\_bus\_device/** - **adafruit\_register/** - **adafruit\_ltr329\_ltr303.mpy** ![CIRCUITPY](https://adafruit.github.io/Adafruit_CircuitPython_Bundle/ltr329_ltr303_ltr329_simpletest.py.png ) ## Python Usage Once you have the library `pip3` installed on your computer, copy or download the following example to your computer, and run the following, replacing  **code.py**  with whatever you named the file: `python3 code.py` ## Example Code for LTR-329 https://github.com/adafruit/Adafruit_CircuitPython_LTR329_LTR303/blob/main/examples/ltr329_simpletest.py **If running CircuitPython:**  Once everything is saved to the  **CIRCUITPY**  drive, [connect to the serial console](https://learn.adafruit.com/welcome-to-circuitpython/kattni-connecting-to-the-serial-console) to see the data printed out! **If running Python: ** The console output will appear wherever you are running Python. ![](https://cdn-learn.adafruit.com/assets/assets/000/116/057/medium800/light_LTR-329_simpletest_serial.png?1666304605) Try covering the sensor with your finger to see the values decrease. Shine a flashlight on the sensor to see them increase. That's all there is to using the LTR-329 with CircuitPython! # LTR-303 Example This example is specific to the LTR-303. It enables the interrupt functionality. To see it working, you'll wire up an LED to the pin. ## LTR-303 Wiring Wire up the LTR-303 as shown here. - **Board 3V**  to **power rail on breadboard (red wire)** - **Sensor VIN** to **power rail on breadboard (red wire)** - **LED + (anode)** to **power rail on breadboard (red wire)** - **Board GND**  to **ground rail on breadboard** **(black wire)** - **Sensor GND** to **ground rail on breadboard (black wire)** - **Board SCL**  to  **sensor****  SCL (yellow wire)** - **Board SDA**  to  **sensor****  SDA (blue wire)** - **LED - (cathode)** to **470Ω resistor** - **Sensor INT** to **470**** Ω **** resistor** ![light_LTR-303_int_LED_breadboard_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/055/medium640/light_LTR-303_int_LED_breadboard_bb.jpg?1666303772) ## Example Code for LTR-303 As explained above, click the  **Download Project Bundle**  button below to download the necessary libraries and the  **code.py**  file in a zip file. Extract the contents of the zip file, and copy the  **entire **** lib ** ** folder ** and the ** code.py ** file to your ** CIRCUITPY** drive. https://github.com/adafruit/Adafruit_CircuitPython_LTR329_LTR303/blob/main/examples/ltr303_advancedtest.py **If running CircuitPython:**  Once everything is saved to the  **CIRCUITPY**  drive, [connect to the serial console](https://learn.adafruit.com/welcome-to-circuitpython/kattni-connecting-to-the-serial-console) to see the data printed out! **If running Python: ** The console output will appear wherever you are running Python. ![](https://cdn-learn.adafruit.com/assets/assets/000/116/056/medium800/light_LTR-303_advanced_test_serial.png?1666304427) Try covering the sensor with your finger to drop it below the lower threshold. The LED should blink regularly indicating the interrupt has been triggered. Try shining a flashlight on the sensor to bring it above the upper threshold. You should get the same result from the LED. That's all there is to using the LTR-303 interrupt functionality! # Adafruit LTR-329 and LTR-303 Light Sensors ## Python Docs # Adafruit LTR-329 and LTR-303 Light Sensors ## Arduino Using the LTR-329 and LTR303 with Arduino involves wiring up the sensor to your Arduino-compatible microcontroller, installing the [Adafruit\_LTR329\_LTR303](https://github.com/adafruit/Adafruit_LTR329_LTR303) library and running the provided example code. ## Wiring Info: Wire as shown for a  **5V**  board like an Uno. If you are using a ** 3V**  board, like an Adafruit Feather, wire the board's 3V pin to the LTR-329 VIN. Here is an Adafruit Metro wired up to the LTR-329 using the STEMMA QT connector: - **Board 5V**  to  **sensor **** VIN (red wire)** - **Board GND**  to  **sensor**  **GND (black wire)** - **Board SCL**  to  **sensor**  **SCL (yellow wire)** - **Board SDA**  to  **sensor**  **SDA (blue wire)** ![light_LTR-329_arduino_STEMMA_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/058/medium640/light_LTR-329_arduino_STEMMA_bb.jpg?1666305452) Here is an Adafruit Metro wired up using a solderless breadboard: - **Board 5V**  to  **sensor****  ****VIN (red wire)** - **Board GND**  to  **sensor**  **GND (black wire)** - **Board SCL**  to  **sensor**  **SCL (yellow wire)** - **Board SDA**  to  **sensor**  **SDA (blue wire)** ![light_LTR-329_arduino_breadboard_bb.jpg](https://cdn-learn.adafruit.com/assets/assets/000/116/059/medium640/light_LTR-329_arduino_breadboard_bb.jpg?1666305504) ## Library Installation You can install the  **Adafruit LTR329 LTR303** library for Arduino using the Library Manager in the Arduino IDE. ![](https://cdn-learn.adafruit.com/assets/assets/000/116/060/medium800/light_Arduino_Open_Library_Manager.png?1666306719) Click the  **Manage Libraries ...**  menu item, search for **LTR329\_LTR303** , and select the  **Adafruit LTR329 LTR303** library: ![](https://cdn-learn.adafruit.com/assets/assets/000/116/061/medium800/light_LTR-329_LTR-303_Arduino_lib_install.png?1666306837) If asked about dependencies, click "Install all". ![](https://cdn-learn.adafruit.com/assets/assets/000/116/062/medium800/light_LTR-329_LTR-303_Arduino_dependencies.png?1666306888) If the "Dependencies" window does not come up, then you already have the dependencies installed.  Warning: ## Example Code https://github.com/adafruit/Adafruit_LTR329_LTR303/blob/main/examples/ltr329_simpletest/ltr329_simpletest.ino ![](https://cdn-learn.adafruit.com/assets/assets/000/116/063/medium800/light_LTR-329_arduino_serial.png?1666307012) Upload the sketch to your board and open up the Serial Monitor ( **Tools -\> Serial Monitor** ) at 115200 baud. You should see the values from the light sensor being printed out. Cover it with your finger to see the values decrease. Shine a flashlight on it to see the values increase. # Adafruit LTR-329 and LTR-303 Light Sensors ## Arduino Docs # Adafruit LTR-329 and LTR-303 Light Sensors ## WipperSnapper ![](https://cdn-learn.adafruit.com/assets/assets/000/128/258/medium800/light_adafruit_products_02_DeviceSelection_croppped.png?1709170396) ## What is WipperSnapper WipperSnapper is a firmware designed to turn any WiFi-capable board into an Internet-of-Things device without programming a single line of code. WipperSnapper connects to [Adafruit IO](https://io.adafruit.com/), a web platform designed ([by Adafruit!](https://www.adafruit.com/about)) to _display_, _respond_, and _interact_ with your project's data. Simply load the WipperSnapper firmware onto your board, add credentials, and plug it into power. Your board will automatically register itself with your Adafruit IO account. From there, you can add _components_ to your board such as buttons, switches, potentiometers, sensors, and more! Components are _dynamically _added to hardware, so you can immediately start interacting, logging, and streaming the data your projects produce without writing code. If you've never used WipperSnapper, click below to read through the quick start guide before continuing. [Quickstart: Adafruit IO WipperSnapper](https://learn.adafruit.com/quickstart-adafruit-io-wippersnapper) ## Wiring First, wire up an LTR-303 or LTR-329 to your board exactly as follows. Here is an example of the LTR-303 wired to an [Adafruit ESP32 Feather V2](https://www.adafruit.com/product/5400) using I2C [with a STEMMA QT cable (no soldering required)](https://www.adafruit.com/product/4210) - **Board 3V**  to **sensor VIN (red wire on STEMMA QT)** - **Board GND**  to **sensor GND (black wire on STEMMA QT)** - **Board SCL**  to **sensor SCL (yellow wire on STEMMA QT)** - **Board SDA**  to **sensor SDA (blue wire on STEMMA QT)** ![light_featherV2_LTR303_STEMMAQT_bb.png](https://cdn-learn.adafruit.com/assets/assets/000/128/269/medium640/light_featherV2_LTR303_STEMMAQT_bb.png?1709171447) ![light_featherV2_LTR303_Breadboard_bb.png](https://cdn-learn.adafruit.com/assets/assets/000/128/270/medium640/light_featherV2_LTR303_Breadboard_bb.png?1709171485) ## Usage Connect your board to Adafruit IO Wippersnapper and **[navigate to the WipperSnapper board list](https://io.adafruit.com/wippersnapper).** On this page, **select the WipperSnapper board you're using** to be brought to the board's interface page. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/261/medium800/light_adafruit_products_02_DeviceSelection.png?1709170500) If you do not see your board listed here - you need [to connect your board to Adafruit IO](https://learn.adafruit.com/quickstart-adafruit-io-wippersnapper) first. On the device page, quickly  **check that you're running the latest version of the WipperSnapper firmware**. The device tile on the left indicates the version number of the firmware running on the connected board. - **If the firmware version is green with a checkmark -**  continue with this guide. - **If the firmware version is red with an exclamation mark "!" -**  [update to the latest WipperSnapper firmware](https://learn.adafruit.com/quickstart-adafruit-io-wippersnapper) on your board before continuing. ![light_adafruit_products_04_LatestVersion.png](https://cdn-learn.adafruit.com/assets/assets/000/128/264/medium640/light_adafruit_products_04_LatestVersion.png?1709170832) ![light_adafruit_products_04_UpdateRequired.png](https://cdn-learn.adafruit.com/assets/assets/000/128/265/medium640/light_adafruit_products_04_UpdateRequired.png?1709170844) Next, make sure the sensor is plugged into your board and click the ** I2C Scan ** button. ![](https://cdn-learn.adafruit.com/assets/assets/000/113/177/medium800/sensor_page_crop_scan.png?1657724520) You should see the LTR-303 or LTR-329's default I2C address of `0x29` pop-up in the I2C scan list. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/272/medium800/light_Screenshot_2024-02-29_015512.png?1709210717) ### I don't see the sensor's I2C address listed! First, double-check the connection and/or wiring between the sensor and the board. Then, reset the board and let it re-connect to Adafruit IO WipperSnapper. With the sensor detected in an I2C scan, you're ready to add the sensor to your board. **Click the New Component button or the + button** to bring up the component picker. ![](https://cdn-learn.adafruit.com/assets/assets/000/127/931/medium800/sensor_page_temperature___humidity_06_AddComponent.png?1708631009) Adafruit IO supports a large amount of components. To quickly find your sensor, type `LTR3` into the search bar, then select the  **LTR-303** or **LTR-329** component. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/273/medium800/light_5ER17lWRqM.png?1709210785) On the component configuration page, the **LTR-303** or **LTR-329**'s sensor address should be listed along with the sensor's settings. The  **Send Every**  option is specific to each sensor's measurements. This option will tell the Feather how often it should read from the LTR-303 or LTR-329 sensor and send the data to Adafruit IO. Measurements can range from every 30 seconds to every 24 hours. For this example, set the  **Send Every ** interval to every 30 seconds. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/274/medium800/light_Screenshot_2024-02-29_020534.png?1709210815) Your device interface should now show the sensor components you created. After the interval you configured elapses, WipperSnapper will automatically read values from the sensor(s) and send them to Adafruit IO. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/276/medium800/light_Screenshot_2024-02-29_125111.png?1709211085) To view the data that has been logged from the sensor, click on the graph next to the sensor name. ![](https://cdn-learn.adafruit.com/assets/assets/000/128/277/medium800/light_ZFLIbSZUMx.png?1709211133) Here you can see the feed history and edit things about the feed such as the name, privacy, webhooks associated with the feed and more. If you want to learn more about how feeds work, [check out this page](https://learn.adafruit.com/all-the-internet-of-things-episode-four-adafruit-io/advanced-feeds). ![](https://cdn-learn.adafruit.com/assets/assets/000/128/275/medium800/light_pHXYJqCLuu.png?1709210922) # Adafruit LTR-329 and LTR-303 Light Sensors ## Downloads ## Files - [LTR-329 Datasheet](https://cdn-learn.adafruit.com/assets/assets/000/115/507/original/LTR-329ALS-01_DS_V1.5.PDF?1664491404) - [LTR-303 Datasheet](https://cdn-learn.adafruit.com/assets/assets/000/115/506/original/LTR-303ALS-01_DS_V1.pdf?1664491385) - [LTR-329 Fritzing object in the Adafruit Fritzing Library](https://github.com/adafruit/Fritzing-Library/blob/master/parts/Adafruit%20LTR-329.fzpz) - [LTR-303 Fritzing object in the Adafruit Fritzing library](https://github.com/adafruit/Fritzing-Library/blob/master/parts/Adafruit%20LTR-303.fzpz) - [EagleCAD PCB files on GitHub](https://github.com/adafruit/Adafruit-LTR-329-LTR-303-PCB) # Schematic and Fab Print LTR-329 ![](https://cdn-learn.adafruit.com/assets/assets/000/115/502/medium800/light_LTR-329_sch.png?1664491093) ![](https://cdn-learn.adafruit.com/assets/assets/000/115/503/medium800/light_LTR-329_fab_print.png?1664491105) # Schematic and Fab Print LTR-303 ![](https://cdn-learn.adafruit.com/assets/assets/000/115/504/medium800/light_LTR-303_sch.png?1664491161) ![](https://cdn-learn.adafruit.com/assets/assets/000/115/505/medium800/light_LTR-303_fab_print.png?1664491189) ## Primary Products ### Adafruit LTR-329 Light Sensor - STEMMA QT / Qwiic [Adafruit LTR-329 Light Sensor - STEMMA QT / Qwiic](https://www.adafruit.com/product/5591) The **Adafruit LTR-329 Light Sensor ** a simple and popular low-cost I2C digital light sensor that is easy to integrate into your project for reliable and wide-ranging light measurements. Perfect for a wide range of project use cases: Should we turn up the... In Stock [Buy Now](https://www.adafruit.com/product/5591) [Related Guides to the Product](https://learn.adafruit.com/products/5591/guides) ### Adafruit LTR-303 Light Sensor - STEMMA QT / Qwiic [Adafruit LTR-303 Light Sensor - STEMMA QT / Qwiic](https://www.adafruit.com/product/5610) The  **Adafruit LTR-303 Light Sensor ** a simple and popular low-cost I2C digital light sensor that is easy to integrate into your project for reliable and wide-ranging light measurements. Perfect for a wide range of project use cases: Should we turn up the... Out of Stock [Buy Now](https://www.adafruit.com/product/5610) [Related Guides to the Product](https://learn.adafruit.com/products/5610/guides) ## Featured Products ### STEMMA QT / Qwiic JST SH 4-Pin Cable - 50mm Long [STEMMA QT / Qwiic JST SH 4-Pin Cable - 50mm Long](https://www.adafruit.com/product/4399) This 4-wire cable is 50mm / 1.9" long and fitted with JST SH female 4-pin connectors on both ends. Compared with the chunkier JST PH these are 1mm pitch instead of 2mm, but still have a nice latching feel, while being easy to insert and remove. Out of Stock [Buy Now](https://www.adafruit.com/product/4399) [Related Guides to the Product](https://learn.adafruit.com/products/4399/guides) ## Related Guides - [Adafruit LTC4311 I2C Extender / Active Terminator](https://learn.adafruit.com/adafruit-ltc4311-i2c-extender-active-terminator.md) - [DIY Pico Mechanical Keyboard with Fritzing and CircuitPython](https://learn.adafruit.com/diy-pico-mechanical-keyboard-with-fritzing-circuitpython.md) - [Using Piezo Buzzers with CircuitPython & Arduino](https://learn.adafruit.com/using-piezo-buzzers-with-circuitpython-arduino.md) - [Launch Deck Trellis M4](https://learn.adafruit.com/launch-deck-trellis-m4.md) - [Halloween Neon LED Signs](https://learn.adafruit.com/halloween-neon-led-signs.md) - [Adafruit USB Host FeatherWing with MAX3421E](https://learn.adafruit.com/adafruit-usb-host-featherwing-with-max3421e.md) - [NeoPixel LED Heart Necklace](https://learn.adafruit.com/neopixel-led-heart-necklace.md) - [Itertools for CircuitPython](https://learn.adafruit.com/itertools-and-functools-for-circuitpython.md) - [PyPortal LIFX Lighting Controller ](https://learn.adafruit.com/pyportal-lifx-lighting-controller.md) - [USB MIDI Keyset Controller](https://learn.adafruit.com/midi-keyset.md) - [NeoPixel Menorah](https://learn.adafruit.com/neopixel-menorah.md) - [QT Py RP2040 USB to Serial MIDI Friends](https://learn.adafruit.com/qt-py-rp2040-usb-to-serial-midi-friends.md) - [Adafruit PiCowBell HSTX DVI Output](https://learn.adafruit.com/adafruit-picowbell-hstx-dvi-output.md) - [Animatronic Hand](https://learn.adafruit.com/animatronic-hands.md) - [Planetary Gear Dreidels](https://learn.adafruit.com/planetary-gear-dreidels.md)