Under Cabinet Dimmable LED Strip Lighting

I started a kitchen LED lighting project this past weekend. I have a galley-shaped kitchen, with a row of cabinets on each side. One side had a tiny little florescent light wired to a light switch. The other side has no lights, but several outlets. No easy way to run wires between the sides. I got a strip of one-color warm LEDs from hitlights.com (these), along with a magnetic dimmable driver (this one). This allowed me to connect the LEDs to a regular 110W Z-Wave dimmer switch. I went with the Cooper (Eaton now) RF9540. I have a SmartThings motion sensor in the kitchen, along with an Echo. When I walk in, the lights fade up to 50%. If I need brighter, I can ask Alexa, or just walk over to the wall switch. Works great so far.

Now I need to do the other side of the kitchen. The plan is to replace one of the wall plugs on that side with Cooper RF9542 (the “accessory” version of the switch) and another identical dimmable driver. Using the smart lighting app, I should be able to keep this side in sync with the other side. Any problems with doing it this way?


The accessory switch will be used just to keep the lights on the left and the right side of the kitchen in sync?

Yeah, the right side only has outlets, and no switches. The plan is to replace an outlet with an accessory switch, so the LED strips on that side will do the same thing the left side LED strips do.

I’m basically thinking of a similar project, although my kitchen is U-shaped so I don’t have the wiring issue. I like your concept and want to mirror something about the same (like you we have an Echo in the kitchen area). I mainly want this 50% fade up to happen especially for those midnight trips for water for my kids.

But I do want to ask why did you choose those lights and that dimmer driver? Have you used that maker before or know anything about them (quality, etc.)?

I researched LED strips-- I wanted bright (these are 384 lumens per foot), warm white, and have a good color rendering index. Plus, they’re reasonably cheap. The driver is made by Magnitude, and is rebranded for use by several other vendors. I like this one because it’s low profile, and I can just mount it under the cabinet with the LED strips.

I’m having an issue-- I’m using the Smart Lighting app to “turn on and set level” to 50% on motion. My wife raised the level to 100% to cook last night, and it kept resetting to 50% because of the motion detection while she cooked. I don’t see a way to manipulate the Smart Lighting app to fix this-- do I have to use a different app?

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There’s an app that I use which captures a new dimmer level and maintains it, while still having motion activate it. So, it specifically does what you want, where it sets it to 50% and then if your wife increases to 100%, it will stay that way until the next time the lights are off.

Cool, thanks for the info.

You may want to look into the CoRE project. It’s rule engine can handle just about anything. I’d think you’d set up a rule that only turns them on at 50% if the state of the light is NOT on (and what time of day restrictions you want).

This is also almost exactly what I am planning to do next month, just with different thresholds. Sometimes younger kid wakes up and trundles to the kitched for a drink of water. And sometimes my older kid comes home late from his labs at college. So what I am planning to do is:

  • After 11pm, if there is no motion, set the lights to 20%
  • If there is motion, set them to %50
  • After 5 min of inactivity, go back to 20%
  • Go to 0% at sunrise
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Love it. Yep, I’ll probably add more changes to mine as well and getting more into CoRE Pistons which enable some fairly complex if/then rule stuff.

I’m happy to also get @ChipChockley opinions on the brand and why he went with them because there are so many makers in this field I kind of wanted to get some good recommendations on a lower priced option (seen other folks recommendations of 10ft strips that were 2x the cost or more) to at least get started with this project since if it works out well, I’d like to add something for master bedroom LEDs behind crown molding, etc.

This app looks perfect, Peter-- I’ll try it out tonight.

Looks like that Motion Lighting app requires Rule Machine, which is now gone? Guess I’ll look into the CoRE stuff…

I had an older version of it. hmmm

Oh, yea, I see where that is. Delete or comment out line 25, and it will work on its own

Thanks, Peter-- deleted that reference and it works great. Does exactly what I want. And I didn’t have to wade into the CoRE waters.

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Thank you @ChipChockley and repliers. We’re remodeling our kitchen now, and I’m removing the existing halogen disk lights. I want to do EXACTLY this, but it will be my very first SmartThings project (I have a ST hub, but it’s still in the box), and I’m a little nervous.

So you achieved a dimming and motion detection setup using the HIT Lights Micro Dimmable Driver that you referenced, paired with a SmartThings compatible dimmer switch and motion detector, correct? Is it still running as expected?

I need about 50 feet of regular density (28w), and the Driver is rated for 60w, so I think I’ll need three Drivers. Is that correct?

Did you consider products like this controller (which would require a power supply, and master)? I’m interested because I was thinking about installing RGB LEDs, and I think the HIT Dimmable Driver only supports monochrome. That said, I’m not comfortable picking H.A. products nilly willy since I’ve never done this before, and the last thing I need is an unreliable lighting project. My wife would kill me.

Final question, do you recommend using aluminum diffuser channels, or did you mount the tape directly to your cabinets?

Yep, all is running well for me with my setup. One change from the setup I first reported was that both sides needed the Cooper RF9540-- the “accessory” version (RF9542) didn’t work for one side like I thought it would. In any event, ST always keeps both sides synced up, whether I use a switch on either side, motion detector turns it all on, or I use the Echo.

Also, I have some flickering issues, concentrated on one side. It doesn’t happen very often, but when it does, it’s really bad. I haven’t tracked down the cause of that yet. HITLights tells me to check all connections, and make sure that my dimmer switch is on the “approved” list for the Magnitude driver. That list is very limited-- only Lutron and Leviton-- but I really don’t think the dimmer is the issue. Still trying to figure that one out.

Oh, and I skipped the aluminum diffuser panels. Works fine with the tape mounted directly under the cabinet. I did have to adjust the placement, though-- sticking the leds too close to the front caused a big shadow line on the counter, since the cabinets have a lip that hangs down. Scoot it back about halfway and it looks great.

I have all of my parts, and I should be installing everything in two weeks (waiting for remodel work to complete). I have a few lingering questions…

  1. Is the 18 AWG wire sufficient for the connections? It seems like a lot of installers use 22 AWG, so I think I’m good, but I just want to make sure.
  2. I’m running 5 sections of LED strip directly to the power supply in parallel (aka home run). Are there any issues with this parallel-wired approach (see diagram)? Assume the power supply is sufficient for the load.
  3. I don’t know how to implement Bruce Ravenel’s code posted above by PeterN. Can someone explain it to me like I’m 5? I think this piece is critical to prevent motion detection from dimming the lights when using the kitchen.

My SmartThings experience: Last night I fired up my hub for the first time. I created a room (“Kitchen”), and added a Motion Sensor device “MD-Kitchen”, assigned it to the “Kitchen” room. I also connected my Echo and my Ecobees to SmartThings. Very cool stuff! I plan to install the Leviton dimmer switch tonight. I’ll have to test with a lamp since I can’t install the LED strips for a while.


Whoa, fancy diagram!

I used 20AWG, cheap stuff I got off Amazon. 18AWG would be fine.

I don’t see any problem running in parallel-- I have two strips running that way for each Magnitude driver. (I just got two of the 40 watts drivers, since I’m just running about 3 meters total off each one. I wired it that way to prevent the dimming you get at the ends when you run long lengths in series.

The code is easy-- log into your SmartThings console (https://graph.api.smartthings.com/), click on “My Smartapps” at the top, then the “+New SmartApp” on the top right, then click “from code” tab, and paste the code from above, but remove line 25 as we discussed. Click “create”, then “publish” on the next page and you’re good. Just use that app rather than the normal “Smart Lighting” app when you set it up in the ST app.

Congrats on getting your ST up and running-- it’s really fun stuff. If you want immediate gratification, go pick up a couple Cree Connected bulbs from Home Depot. They’re only $15 each, and give you a fully ST/Echo controllable/dimmable light, for really cheap. I have them all over my house.

Thanks for those steps, I’ll try it tonight. It looks like Bruce actually removed the RuleMachine reference in his code, so that’s good.

Yes, I have a six pack of CREE connected bulbs coming tomorrow, I can’t wait to get rid of those manual timers that require constant adjustments. I also have a lamp control coming for our Christmas tree, and a GE outdoor controller for our Christmas lights. I have have a few more motion sensors, another dimer wall switch (earmarked for the lights over the stairs), and a non-dimming wall switch on the workbench, waiting for deployment.

Thanks again for the inspiration and help.

I was thinking of picking up the GE outdoor switch, but my old electro-mechanical switch still works so it’ll wait till next year. And I also have kitchen lighting on the agenda. I’m simply waiting for the old fluorescents to finally give up the ghost, while I prep the wife in other rooms before invading her domain :wink:

It’s been a while, overall, we’re really happy with the new kitchen and these lights. We love the natural white color of the LED strips (aka daylight), the dimming capability, and motion detection feature. All of the kitchen lights are controlled by ST at this point.

Lessons learned: The wire I selected was way too thick and stiff, and you couldn’t move the lights without the solder points breaking off of the strips, so I changed to a 20AWG stranded wire, which was more flexible, and worked much better.

The longest run on the tops of the cabinets is the full 5M, and it definitely dims down at the end. It’s only really noticeable if you look for it, but one of these days I plan to cut that strip in half, and run another wire to the PSU.

The lights have a very brief flutter every now and then, maybe once or twice a day. It’s not really a problem because it’s so infrequent, but it is noticeable because the lights are so bright. I’m considering switching out the Lutron dimmer switch with a non-dimming switch as a troubleshooting step. I’m also curious if other appliances are causing interference. I’m only using about half of the power supply’s capacity, so I don’t think it’s being caused by overdriving, and it happens regardless of dimmer setting (100%, 75%, 25%, etc.).


I need to spend more time with SmartThings. I haven’t figured out how to turn stuff on/off with the Echo yet. I’m also not sure that I am going about scheduling things the best way, I have a huge messy list of scheduled items, and it’s difficult to look at it, and know what thing does what action, when, why, etc. I have 6 CREE bulbs, a handful of motion detectors, some lamp modules, and three in-wall switches (one of which controls these cabinet lights).

Since all of these kitchen lights and lamps in the adjoining family room are on ST, and most are on dimmer controllers, I need to look into scenes. I think that will be a compelling use-case (‘cooking’, ‘tv watching’, ‘entertaining’, etc). I know nothing about scenes yet.

I have two minimotes that I need to connect to ST so that we can control the lamps in the living room without having to get out smartphones or yell at the echo, and probably control kitchen scenes as well(?).

A few pictures, the computer nook is out of frame to the right, but has the same lights.