BH1750 — i2c address & wiring
Digital ambient light sensor with lux output.
Key facts
BH1750 at a glance
| i2c address | 0x230x5C address-selectable via pins/jumpers |
|---|---|
| Logic voltage | 3.3–5 V |
| Type | sensor |
| Part | Rohm BH1750 |
| Ships with | Qwiic, STEMMA QT, Grove |
The chip
What the Rohm BH1750 actually is
Digital ambient light sensor measuring illuminance directly in lux. Provides calibrated light intensity measurements over a wide dynamic range with selectable measurement modes for automatic brightness control and environmental monitoring.
Wiring
How to connect the BH1750
The BH1750 talks i2c at address 0x23 (up to 2 selectable addresses, handy when you need more than one on the same bus). It runs at 3.3–5 V, so match your host's logic level — if your host is 5 V and a board on the bus is 3.3 V-only, add a level shifter. Use the compatibility checker to confirm the exact cable for your setup.
Because the address is selectable, you can run several BH1750 boards on one bus by setting each to a different address — no extra wiring beyond the shared SDA/SCL.
Wiring is the usual four: power, ground, SDA and SCL, plus pull-up resistors — almost always already fitted on the breakout. Nothing showing up? Run an i2c scan first; if the bus is silent, the 7-step checklist finds it faster than guessing.
Ecosystems
Plug-together options for the BH1750
BH1750 breakouts ship with Qwiic, STEMMA QT and Grove — keyed 4-pin cables carrying power, ground, SDA and SCL, so there's nothing to solder and nothing to wire backwards. Chain it to the next board and keep going.
Running a mixed bench? Those ecosystems interoperate more than their marketing suggests — see every connector pairing for the cable or adapter you need, or the standards overview for how they compare.
Go deeper
Guides covering the BH1750
Alternatives
Other light boards
Watch the bus
Boards that clash with the BH1750
These want an address the BH1750 also answers (0x23), so they can't share a bus with it untouched. If one is address-selectable, strap it elsewhere; if not, the conflict guide covers the multiplexer and second-bus routes, and the collision roundup explains why a scan won't warn you.
Get one
Questions
BH1750 i2c FAQ
What is the BH1750's i2c address?
The BH1750 uses 0x23 or 0x5C, selected with an address pin or solder jumper on the board. If a scan turns up something unexpected, our i2c address list names the usual suspect for every address.
What voltage does the BH1750 run at?
3.3–5 V logic. That range covers both 3.3 V and 5 V hosts, so it drops onto a Pi, ESP32 or Arduino without a level shifter.
Can I use two BH1750s on one i2c bus?
Yes — set each one to a different address (0x23, 0x5C) using its address pin or jumper, then wire both to the same SDA/SCL. That gives you up to 2 on a single bus before you need a multiplexer.
Does the BH1750 work with Qwiic and STEMMA QT and Grove?
Yes — BH1750 breakouts ship with Qwiic / STEMMA QT / Grove, so it plugs straight in with no soldering. Mixing ecosystems? The compatibility checker gives you the exact cable or adapter.