In FLS-M Config-Builder Advanced Light Options, there’s a Constant Brightness setting with the tooltip, “Maintains constant brightness across chromaticity shifts (sacrifices max brightness)”. For a Non-addressable (PWM) CT (WW + CW) light where this is NOT selected, does that mean that when the color temperature requested in Matter is the average of the warm and cool white LEDs and the brightness requested is 100%, that both the WW and CW channels will run at FULL brightness? That is to say twice the power output of when only one channel is at 100% I sure hope so, because I’ve been looking for exactly this in an LED strip controller for years.
The constant brightness option is still a bit experimental, but I’m open to experimenting with it since we are still looking for a use case.
Essentially, the FLS-M uses linear algebra to solve for an LED ratio that results in the desired chromaticity.
For example, let’s say you want yellow, which is 50% red and 50% green.
Without the constant brightness option, this ratio is simply scaled up to the desired level. So if I want 70% brightness yellow, that would result in 70% red brightness and 70% green brightness.
With the constant brightness option, this scaling step is skipped, and the desired brightness is distributed across the available LEDs.
So, 70% yellow would result in 35% red brightness and 35% green brightness.
It’s important to mention that in both cases there is still a gamma correction step, which compensates for the logarithmic sensitivity of our eyes.
I don’t know if this is the feature you are looking for, but I’m open to adjusting the firmware to achieve your desired result.
Regards,
Ericp
It seems like without the Constant Brightness option is what I want, but I want to confirm for a white adjustable (WW + CW only) strip.
If the Warm White channel is configured with:
- X Position: 0.457
- Y Postion: 0.409
- [Effective color temperature: 2727 Kelvin]
- Intensity: 1
And the Cold White channel is configured with:
- X Position: 0.33
- Y Postion: 0.33
- [Effective color temperature: 5613 Kelvin]
- Intensity: 1
So if I want 100% brightness at 4170 Kelvin, what will be the warm white and cool white brightness? I’m hoping it will be 100% and 100%, not 50% and 50%. Thanks again!
Yes. I would be 100% : 100% without the constant brightness enabled
An FLS-M arrived. My existing configuration is two CT LED strips wired in parallel with one Zigbee C01Z controller driving the WW LEDs and another C01Z driving the CW LEDs. With both drivers set to 100% brightness, the load to my power supply is 102 watts. Moving the LED strips to the FLS-M (firmware version 1.1) as two separate CT lights (via Config-Builder), setting the color temperature to the middle 3,816K of the range advertised (2,695-6,535K), and brightness to 100%, the load to my power supply is 94 watts. A decrease of 8%, but that’s fine. It’s not enough of a difference to worry about.
I suspect the effect comes from a higher voltage drop across a single controller compared with two in parallel. You could verify this by running four independent channels, which should result in the same power draw.
Because human brightness perception is roughly logarithmic, the change from 94 W to 102 W is unlikely to be noticeable. And if you account for the extra controller losses, the net difference is about 6 W.
I figured it might have to do with electrical configuration. And yes, I have an adjacent identical pair of LED strips running the old configuration with two single channel controllers driving the LED strips in parallel. I cannot discern a difference in brightness from the two LED strips running off one FLS-M. I don’t want to reconfigure the FLS-M right now, but I might experiment with individual channels at some point in the future.
Having Constant Brightness as a configurable setting is fantastic, thanks!