Composite Device Guide - Smart (Components) Toolkit for Homey

What It Does

A Composite Device watches two or more Homey devices that share a capability, such as measure_humidity, measure_temperature, or alarm_contact. Whenever a source changes, the virtual device recalculates its output.

Native-looking output

Numeric values retain their source unit and decimals. Boolean results appear as an alarm. Text and clock results appear as text.

Realtime and resilient

Source listeners update the result immediately. A periodic refresh reconnects missing or restarted sources.

Setup

Add Composite Device from Smart (Components) Toolkit.
Select the capability to combine. Only capabilities found on at least two devices are shown, and units must match.
Select a calculation. The available list changes for numbers, booleans, and text.
Select at least two source devices, choose a name, and create the device.

The source list and operation are fixed when the device is created. To use a different set, add another Composite Device.

Install latest test version (v1.10.23) →

Calculations

Source	Operations	Output
Number	Average, minimum, maximum, sum, median	Numeric measure with source unit
Boolean / alarm	Any/maximum, all/minimum, majority, count on, percentage on	Alarm or numeric measure
Text / enum / clock	Most common, min/earliest, max/latest, most recently updated, average clock time	Text

Flow Triggers

Composite value changed

Fires for every real change after the initial startup value. It supports numeric, boolean/alarm, text, enum, and clock outputs. Tags contain the current value, previous value, value type, and device name; the universal values are text tags so one card works for every output type.

Composite value changed by more than...

For numeric Composite Devices. Enter a non-negative threshold and choose fixed units or percent. The card fires only when the absolute difference from the preceding exposed value is strictly greater than that threshold.

Percentage change is calculated against the absolute previous value. A transition from zero to a non-zero value counts as 100%. Tags include current and previous value, signed change, absolute change, and percentage change.

The first aggregate after app or device startup establishes the baseline and does not fire either card. Thresholds compare consecutive exposed values; they are not cumulative across several smaller changes.

Examples

Highest humidity: select Humidity, all five humidity sensors, and Maximum.

Any open door: select Contact Alarm and Any / Maximum. The Composite alarm is on if one or more contacts are open.

Average temperature: select Temperature and Average. The output keeps the temperature unit and display precision.

Average clock time: select a text capability containing HH:mm or HH:mm:ss and Average Clock Time. Clock arithmetic is circular: 23:00 and 01:00 average to 00:00.

Missing Values and Source Error

Null, invalid, or unavailable sources do not prevent the remaining valid sources from contributing. The Source Error alarm turns on whenever fewer than all selected sources are contributing.

If no valid source remains, the Composite Device becomes unavailable. It automatically becomes available again when a valid source returns.