Dimming light below 10% via smartapp?

(Sean) #1

I am looking for a smartapp similar to smart light app, only it will allow dimming below 10%. What I’m trying to do is have my daughters light turn on and dim to 3% when motion is detected between a certain time period. Can anyone suggest an app/ solution? Thanks!


Many LEDs just won’t dim that low. Smart or not. Just has to do with the physics of how they dim. It’s not that they can’t dim, but rather that the switches don’t provide the kind of drivers they need to dim that low.


There are much more expensive switches that can do a better job of low dimming but most people aren’t willing to pay for them.

There are cheaper switches that condemned that low, but they may give off electromagnetic interference, so the zwave device manufacturers don’t use them.

There is also a variation between LED brands, smart or not.

What model switch and bulb are you intending to use?

(Dale C) #3

@JDRoberts has great insight for you to consider. That being said you could easily do this with CoRE by @ady624 if you want to load a beta version but know about the limitations of your hardware. I am interested in your answer for JDRoberts, what hardware you are using?

( I hate Mondays) #4

LEDs are diodes. By nature, diodes have a minimal forward voltage that “opens” the gate. This is typically 0.6V. Anything over that turns the LED on and its brightness varies with the forward voltage applied. However, the LED is off between 0 and 0.6V. This is the same reason “lamp” amplifiers have more fidelity that simple transistor amplifiers. Dimming can be implemented by varying said forward voltage - which means you cannot cover the low range because the diodes will simply turn off below anything around 10%. The alternative is using time division to turn the diode on for very short periods of time, varying the percentage of time on vs time off to achieve a dim level. This is much more expensive…


It’s certainly worth trying to see if it works with the devices you are already using. :slight_smile:

CoRE is a new rules engine which is still in the early design phase. So there may be glitches, and you may have to uninstall and reinstall in the future as changes are made. It’s also very sophisticated, with a complex setup. So if you just want to solve this particular use case, you might try a simpler smartapp for now. If you want to get in on and influence the development of what I’m sure will be a major new smartapp, look into CoRE.

If you’d like to look at some of the simpler but more mature lighting smartapps, choose the Lighting link on the quick browse page:


Another Option: a Smart Nighlight with 8 color notifications

BTW, for a different approach, Homeseer has a zwave nightlight that has its own motion sensor and can change to one of 8 colors, including pink and purple, which is fun for a child’s room and lets you give multiple notifications. You can also pretty it up by putting daisy petals around the central light.

A number of community members have used it. It’s on pre-order right now because they’re getting ready to release a zwave plus version, but it might be worth waiting for.