Adafruit
Adafruit ALS-PT19 Analog Light Sensor Breakout
The Adafruit ALS-PT19 is a compact analog light sensor that provides a simple voltage output proportional to ambient light intensity. Its spectral response c...
The Adafruit ALS-PT19 is a compact analog light sensor that provides a simple voltage output proportional to ambient light intensity. Its spectral response closely matches that of the human eye, thanks to a high infrared rejection ratio — making it ideal as an RoHS-compliant upgrade from traditional photocells.
Wiring is straightforward: connect power (2.5–5.5V), ground, and read the analog voltage on the OUT pin. The voltage increases as the sensor detects more light.
Key Features
- Analog Output – Simple voltage output proportional to light level, read with any ADC
- Human-Eye Spectral Response – High infrared rejection for accurate ambient light sensing
- Wide Voltage Range – Operates from 2.5V to 5.5V
- RoHS Compliant – Suitable for projects requiring lead-free components
- Compact Breakout – Tiny PCB with simple three-pin interface
Ideal For
- Ambient light level detection
- Automatic backlight or LED brightness control
- Day/night sensing
- Replacing photocells in RoHS-compliant designs
Package Contents
- 1× Adafruit ALS-PT19 Analog Light Sensor Breakout
Jargon buster
Plain-language definitions for the technical terms used above.
- ADC
- An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- LED
- A light-emitting diode is a small electronic component that lights up when current flows through it in the correct direction. In this kit, LEDs create the flashing effect, so polarity and correct soldering matter for the project to work.
- PCB
- A printed circuit board is a rigid board with copper tracks that connect electronic parts without loose wires. For this kit, the PCBs also form the airplane shape, so they are both the circuit base and part of the finished model.
Find this product in
Brands
Sensors & Input
Related Tutorials
Free guides on learn.littlebird.com.au
