Device settings

Dimmer settings

Calibration against the connected load, fade time, and limits on how dark or bright the dimmer goes - what sets a dimmer apart from a plain relay.

Dimmers share power-on behaviour, input mode and protection limits with Common settings - a dimmer's initial_state can also be toggle, in addition to off/on/restore_last. What's specific to dimmers is calibration, brightness limits and fade.

Calibration

A dimmer needs to "learn" the connected load to dim smoothly without flicker or humming. This mainly applies to in-wall dimmers like the Shelly Dimmer, where you choose a dimming type:

• Trailing edge - recommended for dimmable LED and low-energy bulbs, gives a smoother start and less wear on the bulb.
• Leading edge - an older method, mainly for resistive/inductive loads such as incandescent bulbs and some halogens.
• Auto-detect - the device tests its way to which type the load needs.
• Calibration with bypass - an option if a bypass unit is connected, which in some cases gives smoother dimming even though it isn't mandatory.

Calibration runs as a separate step in the web interface or app after installation, not as an ongoing setting - re-run it if you change the type of bulb.

Brightness limits

• min_brightness_on_toggle - the brightness the dimmer goes to when switched on from fully off, if the brightness would otherwise end up at an unusable level.
• range_map - remaps the internal 0-100 range, useful if the bulb doesn't respond linearly or doesn't go fully dark at 0%.
• gamma - a correction factor (0.4-4.0, default 1.0) for how the brightness curve is perceived, since the eye doesn't perceive brightness linearly.

Fade

transition_duration controls how many seconds it takes to go from 0 to 100% brightness (or between two levels), instead of an instant jump. button_fade_rate does the equivalent for how fast brightness changes while you hold down a physical button to dim.

Night mode

night_mode.enable, with night_mode.brightness as a ceiling on brightness and night_mode.active_between as a time range ([start, end] in HH:MM format), keeps the dimmer from going above a certain level at night - regardless of what's requested from the app or an automation.

Warm-up

Some bulbs - certain LED types especially - need a brief moment at full power to light reliably before dimming down to the requested level. warmup.enable, warmup.brightness and warmup.time_ms control this behaviour.

Protection

Just like relays, dimmers with power metering have power_limit, voltage_limit, undervoltage_limit and current_limit - see Common settings for how they work.