BH1750 with Raspberry Pi Pico 2

Wiring for the GY-302 BH1750 light sensor on the Raspberry Pi Pico 2 (RP2350, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

BH1750 pin	Role	Raspberry Pi Pico 2 pin	Notes
VCC	Power	3V3(OUT)
GND	Ground	GND
SCL	I2C clock (SCL)	GP5
SDA	I2C data (SDA)	GP4
ADDR	Not wired to the board	not connected	Address select: LOW or open = 0x23, HIGH = 0x5C

Check before you power it on

Supply: 3.3 V from the 3V3(OUT) pin.
I2C uses the board’s default pins GP4 (SDA) and GP5 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = GP4, SCL = GP5 (the board's default I2C pins)
  Wire.beginTransmission(0x23);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "GY-302 BH1750 light sensor found at 0x23" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Arduino board: rp2040:rp2040:rpipico2. If the board is not found, hold the BOOTSEL button while plugging in the USB cable.

Questions

Which Raspberry Pi Pico 2 pins do I use for the BH1750?

VCC → 3V3(OUT), GND → GND, SCL → GP5, SDA → GP4.

Does the BH1750 work with the Raspberry Pi Pico 2 at 3.3 V?

Yes: the BH1750 runs at 3.3-5 V and the Raspberry Pi Pico 2 uses 3.3 V signals, so no level shifting is needed.

What is the I2C address of the BH1750?

0x23 or 0x5C. An I2C scan (BoardPilot does it for you) shows which one your module uses.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Raspberry Pi Pico 2 pinout · GY-302 BH1750 light sensor: all pins and data

The BH1750 on other boards

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