Overview

The APDS-9301 is a low-voltage 16-bit digital ambient light sensor (ALS) manufactured by Broadcom (formerly Avago Technologies). Housed in an ultra-small 2.6×2.0 mm2.6 \times 2.0\text{ mm} 6-pin ChipLED package, it converts illuminance (Lux) into digital I2CI^2C output codes.

The APDS-9301 incorporates two integrating photodiodes on a single chip:

  • Channel 0 (CH0): Detects both Visible and Infrared (IR) light.
  • Channel 1 (CH1): Detects Infrared (IR) light only.

By subtracting Channel 1 from Channel 0 in software, the sensor compensates for ambient IR background radiation (from incandescent bulbs or sunlight), providing a human-eye spectral response curve across illuminance levels from 0.1 Lux to 40,000 Lux.

Quick reference

Operating voltage (VCC)2.7 V to 3.6 V DC (3.0 V nominal)
InterfaceI2CI^2C (up to 400 kHz)
Default I2CI^2C address0x39 (ADDR pin floating); configurable to 0x29 (GND) or 0x49 (VCC)
Dynamic range0.1 Lux to 40,000 Lux
Internal ADCsDual 16-bit integrating ADCs (CH0 & CH1)
Operating current240 μA240\ \mu\text{A} active / 3.2 μA3.2\ \mu\text{A} power-down
Interrupt outputProgrammable threshold INT pin

Pinout

Standard 5-pin 0.1" (2.54 mm) breakout module header:

PinNameTypeDescription
1VCCPowerSupply voltage (+2.7 V to +3.6 V DC)
2GNDPowerGround (0 V)
3SDADigital Input / OutputI2CI^2C Serial Data
4SCLDigital InputI2CI^2C Serial Clock
5INTDigital OutputActive-Low interrupt output (programmable lux thresholds)

Specifications

ParameterSymbolMinTypMaxUnitConditions
Supply VoltageVDDV_{DD}2.73.03.6VDC
Active Supply CurrentIDDI_{DD}—240350µAActive integration state
Power-Down CurrentIpdI_{pd}—3.26.0µASoftware power-down
I2CI^2C Clock FrequencyfSCLf_{SCL}0100400kHzStandard / Fast mode
Integration Time (13.7ms)tint1t_{int1}13.013.714.4ms13-bit max count (5,047)
Integration Time (101ms)tint2t_{int2}96101106ms15-bit max count (37,177)
Integration Time (402ms)tint3t_{int3}382402422ms16-bit max count (65,535)

I2CI^2C Protocol & Lux Calculation

To calculate true Lux from raw channel readings (CH0CH0 and CH1CH1):

  1. Calculate Ratio: R=CH1CH0R = \frac{CH1}{CH0}.
  2. Apply Empirical Formula (for 0<R≤0.520 < R \le 0.52):

Lux=0.0304×CH0−0.062×CH0×(CH1CH0)1.4\text{Lux} = 0.0304 \times CH0 - 0.062 \times CH0 \times \left( \frac{CH1}{CH0} \right)^{1.4}

  1. High IR Conditions (0.52<R≤0.650.52 < R \le 0.65):

Lux=0.0224×CH0−0.031×CH1\text{Lux} = 0.0224 \times CH0 - 0.031 \times CH1

Wiring

APDS-9301 Pin→Arduino Uno (with 3.3V supply)ESP32Notes
VCC3.3V3.3VDo not connect to 5V
GNDGNDGNDSystem ground
SDAA4GPIO 21I2CI^2C Data
SCLA5GPIO 22I2CI^2C Clock

Example

cpp
#include <Wire.h>

#define APDS9301_ADDR 0x39

void setup() {
  Serial.begin(9600);
  Wire.begin();

  // Power ON sensor (Control Register 0x80 = 0x03)
  Wire.beginTransmission(APDS9301_ADDR);
  Wire.write(0x80); // Command byte + Control Register
  Wire.write(0x03); // Power ON
  Wire.endTransmission();
}

void loop() {
  // Read CH0 LSB & MSB (Register 0x8C)
  Wire.beginTransmission(APDS9301_ADDR);
  Wire.write(0xAC); // Command word + Word read starting at 0x0C
  Wire.endTransmission();

  Wire.requestFrom(APDS9301_ADDR, 2);
  uint16_t ch0 = Wire.read() | (Wire.read() << 8);

  Serial.print("Channel 0 (Visible+IR) Raw: ");
  Serial.println(ch0);

  delay(500);
}

Common mistakes

  • Powering VCC directly from a 5V rail: The APDS-9301 absolute maximum supply voltage is 3.8V. Supplying 5V destroys the ChipLED package.
  • Forgetting the command bit 0x80 in I2CI^2C writes: Every register address write to APDS-9301 must set bit 7 (0x80) of the command byte to indicate a valid register select.

Notes

  • APDS-9301 vs TSL2561: Broadcom APDS-9301 and ams TSL2561 share functionally identical dual-channel architectures and I2CI^2C command registers.

Assets & downloads