Light Sensor

The HomeKit light sensors have a number of common options and are grouped here.

Type	Service Type
50	Light Sensor

The following configuration is available:

Section	Key	Description
Wildcard Actions	"y[n]	Perform an action when a service reaches a target lux value
Sensor Type	"n"	Type of sensor attached to service
GPIO	"g"	GPIO used by ADC for ESP32 chips
Configuration Data Array	"dt"
Resistor Value	"re"
Power Value	"po"
Sensor Polling Time	"j"	Frequency sensor is read
Light Sensor Factor	"f"	Correction factor to apply
Light Sensor Offset	"o"	Correction offset to apply
Service Characteristics

Example 1

{
  "c": { "io": [ [ [ 13 ], 2 ] ], "l": 13 },
  "a": [{
    "t": 50,
    "n": 0,
    "f": 14357564.33,
    "po": 1.396066767,
    "re": 8550
  }]
}

Sensor Type

Sensor type is defined by the "n" key contained within the service object.

Key	Type	Description
"n"	-1	Virtual sensor
	0	ADC (default)
	1	ADC
	2	BH1750. Requires I2C bus declaration

GPIO

Only needed for ESP32, because ESP8266 has only one ADC pin.

Remember to declare GPIO as ADC into "io":[...] array. See GPIOs Configuration

Key	Type	Description
"g"	integer	GPIO number

Configuration Data

Array with information about sensor. For BH1750, "dt" key must be in this format: "dt" : [I2C Bus, Address]

Code Address as follow:

Addr Pin	Address
LOW / GND	35
HIGH / VCC	92

Resistor Value

TO-DO

Power Value

TO-DO

Sensor Polling Time

Sensor polling time is defined by the "j" key contained within the service object.

Key	Value	Description
"j"	3	Sensor is polled every 3 seconds (default)
	0.1 to 65535	Float specifying the number of seconds between polls

A light sensor is polled on a regular basis to read the latest values. These values are then posted to HomeKit. If this option is not specified then the sensor will be polled once every 3 seconds.

Light Sensor Factor

Light sensor factor is defined by the "f" key contained within the service object.

Key	Value	Description
"f"	1	No factor is applied (default)
	-∞ to +∞	factor is applied to lux value read

The option uses is a floating point value, accurate to 1 decimal place e.g. 1.1

Light Sensor Offset

Light sensor offset is defined by the "o" key contained within the service object.

Key	Value	Description
"o"	0.0	No offset is applied (default)
	-∞ to +∞	Offset is added to lux value read

The option uses is a floating point value, accurate to 1 decimal place e.g. 1.1

Wildcard Actions

Wildcard Actions "y[n]" are supported by this service. The supported list is:

Key	Action
"y0"	Trigger action when service reaches a specific lux value

Refer to Wildcard Actions for more detail.

Service Characteristics

Characteristic	Description
0	* Current light level