Overview
The bh1750 node reads ambient light levels from the BH1750 digital light sensor.
It directly outputs light intensity in lux (no manual calibration needed), making it ideal for
automatic brightness control, daylight harvesting, and grow light management.
1-65535
Lux Range
16-bit
Resolution
I2C
Interface
3.3V
Power
Light Levels Reference
| Environment | Lux |
|---|---|
| Moonlight | 0.1 - 1 |
| Street lighting | 10 - 20 |
| Living room | 50 - 300 |
| Office lighting | 300 - 500 |
| Overcast day | 1,000 - 2,000 |
| Full daylight | 10,000 - 25,000 |
| Direct sunlight | 32,000 - 130,000 |
Properties
| Property | Type | Default | Description |
|---|---|---|---|
| address | number | 0x23 | I2C address (0x23 or 0x5C) |
| mode | string | "continuous" | "continuous" or "oneshot" |
| resolution | string | "high" | "high" (1 lux), "high2" (0.5 lux), "low" (4 lux) |
| interval | number | 1000 | Reading interval (ms) |
Output
{
"payload": 342.5,
"unit": "lux",
"timestamp": 1640000000000
}Example: Automatic Blinds Control
Control motorized blinds based on ambient light levels.
// Function node: Blinds position logic
var lux = msg.payload;
var position;
if (lux > 30000) {
position = 100; // Fully closed - too bright
} else if (lux > 10000) {
position = 75; // Mostly closed
} else if (lux > 1000) {
position = 50; // Half open
} else if (lux > 100) {
position = 25; // Mostly open
} else {
position = 0; // Fully open - it's dark
}
msg.payload = {
lux: lux,
blindsPosition: position,
action: "set_blinds"
};
return msg;