Configurable Perceptual Dimming Curves

Innovation & Firmware Discussion Feature Suggestions
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I have both Inovelli Red Series VZW31-SN dimmers (~10) and couple Lutron Caséta dimmers installed in my home, controlling the same model of dimmable LED bulbs.

The difference in dimming behavior is substantial.

With the Inovelli, holding the paddle to dim the lights produces relatively little perceived brightness change through much of the upper range. Most of the noticeable change occurs near the bottom, where the lights suddenly become much darker.

The Lutron Caséta provides a much more natural and consistent perceived brightness transition using the same bulbs.

This is not primarily a dimming-speed issue. Slowing down the ramp doesn’t change the distribution of perceived brightness across the dimming range.

It’s also not something I want to solve by reducing the maximum dimming level. While it that can help make it feel like the dimming is more gradual over the range, it reduces that actual amount of illumination even if it “feels” the same and can have an impact on things like photos taken in the room.

Feature Request

I’d love to see an option for configurable nonlinear dimming curves, allowing the perceived brightness to change more evenly throughout the dimming range.

Ideally, this would:

  • Provide a more consistent perceived brightness change when holding the physical paddle.

  • Preserve the full 100% light output. I don’t want to sacrifice maximum brightness to improve the dimming experience.

  • Apply to both physical paddle dimming and Z-Wave brightness commands.

  • Offer a few selectable dimming curves, or potentially a configurable gamma value, so users can tune the behavior to their bulbs.

  • Retain the current dimming behavior as the default for backward compatibility.

I really love how configurable these switches are, but the dimming behavior is one of my biggest complaints. If i want to quickly dim a room I regularly find myself having to pull out my phone and open an app to set the switch to a low value because trying to nail the exact right level without having a really slow dimming speed is really painful.

I have seen a couple threads that mention this issue in passing, but dont think i’ve seen an answer on the feasibility of the feature

I use Home Assistant with Z-Wave JS and would be happy to help test a beta implementation.

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I completely agree with this suggestion. Based upon readily available descriptions of dimming curves and the dimming behavior described here (which I too perceive) I suspect Inovelli uses a linear model which seems to be a problem shared with other smart dimmer devices. A tunable dimming curve using a gamma value would fit with the maximal customizability paradigm advertised by Inovelli, but may not be necessary as the vast majority of use cases would be satisfied with the standard perceptual correction. Just like we don’t select between curves for volume controls (loudness is also perceptually logarithmic), we probably don’t need to select between brightness dimming curves.

In general, humans seem to perceive all stimuli on a logarithmic scale, known as the Weber–Fechner Law (bonus points to @gpiper for triggering a Wikipedia expedition!).

I’m surprised that Inovelli hasn’t implemented logarithmic/fixed-gamma dimming behavior yet. @EricM_Inovelli, is this something that has been considered?