---
title: "light on · RUAL Documentation"
description: "Turns a light on. Optionally set brightness, colour temperature or colour in the same command."
canonical: https://docs.rual.nl/block-types/globals/homeassist_light_on
language: en
---

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Other

# light on

This block is part of the [`globals`](https://docs.rual.nl/block-types/globals) group and was last modified in core [`v15.0.0`](https://docs.rual.nl/core-versions/150000).

Turns a light on. Optionally set brightness, colour temperature or colour in the same command.

- flow `v15.0.0` `flow`

- device `v15.0.0` `value` Device id, native address, or exact device name. Leave empty to use the device picked on the block.

- brightness % `v15.0.0` `number` 0-100. Leave empty to keep the current brightness. • Min: 0 • Max: 100

- kelvin `v15.0.0` `number` Colour temperature in kelvin: 2200 candle, 2700 warm white, 4000 neutral, 6500 daylight.

- colour `v15.0.0` `value` Hex colour, #rrggbb. Ignored by white-only bulbs.

- flow `v15.0.0` `flow`

- ok `v15.0.0` `condition` True when the command reached the device.

- device `v15.0.0` `object` The device the command was sent to.

- error `v15.0.0` `value` Empty on success. HOMEASSIST_DEVICE_NOT_FOUND, HOMEASSIST_DEVICE_NOT_ADOPTED, HOMEASSIST_CAPABILITY_UNSUPPORTED or HOMEASSIST_NOT_AVAILABLE.

Turns on a light over the local radio (Zigbee, Thread/Matter, Z-Wave) or a Hue bridge. Brightness is 0-100 percent, colour temperature is in KELVIN (2700 warm, 6500 cold) not mireds, colour is #rrggbb. Every value set here is sent in ONE command, so the lamp transitions once instead of visibly stepping through full brightness first. Unset pins leave the lamp's current value alone.

| `zigbee` |
| --- |
| `zwave` |
| `matter` |
| `thread` |
| `hue` |
| `smart home` |

[light on](https://docs.rual.nl/block-types/home/homeassist_light_on) carries brightness, colour temperature and colour on its own pins, and sends every value that is set in ONE command, so the lamp transitions once instead of visibly stepping through full white first. Brightness is a percentage and colour temperature is in KELVIN, not mireds: 2200 candle, 2700 warm white, 6500 daylight. The device pin takes a platform id, a native address or an exact device name.

[![Studio canvas example for the light on block: on, warm and dimmed, in one command.](https://docs.rual.nl/canvas-examples/homeassist_light_on.png)](https://docs.rual.nl/canvas-examples/homeassist_light_on.png?v=3)

## Used in these guides

These documentation pages use or explain this block:

- [Action Reference](https://docs.rual.nl/home-automation/actions)

## Version history

Introduced in [`v15.0.0`](https://docs.rual.nl/core-versions/150000).

- [Back to `globals`](https://docs.rual.nl/block-types/globals): Return to the main group to view all sub-groups

- [Back to `home`](https://docs.rual.nl/block-types/globals?group=home): Return to the group to view all blocks within this group

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