automatic led lamp dimmers

System

hi, everyone.

i have tried searching online but cannot seem to find automatic LED lamp dimmers that can work our lamp like this. (we want to modify its working based on traffic flow pattern)
7pm-12am= 100% brightness
12am-5am= 50% brightness
5am- 7am =100% brightness.

can we get a dimmer that can automatically achieve this?
it will make our system requirements better and save us costs too.

many thanks,
alex

BB.

Re: automatic led lamp dimmers

Alex, there are several issues...

First, LED's do not connect directly to 230 VAC... They instead have some sort of electronics that drop the voltage, change it to DC, and control the current (a ballast).

These ballasts can be designed/built many different ways--and they will respond to lamp dimmers (filament dimmer which chops the AC sine wave, transformers which drop the AC voltage, a diode which cuts 1/2 of the AC voltage, etc.) differently. Many will not reduce LED brightness, and some will overheat and fail with one or more of the typical lamp dimmer types I listed. So--you would have to research/experiment to see if the setup you have would respond as you desire or not.

Second, you actually probably want to reduce LED brightness by way more than 1/2 power... More than likely 1/10th power or even more reduction. Depending on the effect you are after, you may wish to reduce the power levels by 1/100 or even 1/1,000.

Our eyes respond to light levels in a "logarithmic" manner. It turns out that a 1/2 power reduction is almost imperceptible to human eyes. A factor of 1/10 reduction is very noticeable. So--you will have to adjust your lighting control plan to account for this issue.

So--My suggestion for something that will be easy, safe, and compatible with the most LED lamps--I would see if you can have two lighting circuits. One that powers (for example) 100 LED lamps, and a second circuit that powers 1/10 or 1/100th the number of LED lamps. Or powers two sets of LED lamps--Once set that is bright/high output. And a second circuit connected to a set of low power LED lamps.

Hope that helps.

-Bill

Seven

Re: automatic led lamp dimmers

You could get two different lamps that have different brighness bulbs and put them on seperate timers. I saw an LED bulb the other day that could be installed in a lamp that was capable of using a dimmer. One of the three click ones. It was at Lowes I think. I have done alot of LED investigation recently because I am replacing every bulb in my house with them.

Side note. The Lowes closest to me is having a clearance on LED night lights. I picked a bunch up for an average of $2 each.

BB.

Re: automatic led lamp dimmers

Sunny Alex is probably out of Nigeria--So, he would need a source more local to him (or some links to examples of what you saw).

-Bill

Seven

Re: automatic led lamp dimmers

Sorry Bill, no links, just something I saw in a store.

Dr. Strangelove

Re: automatic led lamp dimmers

Alex, you need to tell us more about your problem before we can find a solution for you. What is your source of power? What voltage? What kind of LED lighting do you have? How much and what power? What is your budget? What are the future plans for the system - will it grow?

If you are starting from scratch, you could consider a 12VAC sprinkler timer and multiple 12VAC LED light assemblies. Or even use a modern 12VAC garden light transformer with a photo-sensor. The latter can do off in day time, and on for 1 or more hours to all night. Dimming would require more glue.

For example, I use a Rainbird SST to control a small indoor pond system: drip irrigation, pond fill valve and a circulation pump (with a relay). Outdoors I'm experimenting with a "Portfolio 120-Watt Magnetic Power Pack with Digital Timer" from Lowes and nifty 12VAC LEDs I found on Amazon. The warm white LEDs are nearly indistinguishable from the 11W incandescent bulbs, except for 9.5W less power. I've also tested these 3W MR16 bulbs and 5W MR16 bulbs - they are awesome. I don't know if the sprinkler timer can handle a multi-Watt load, but you're just a relay or two away.

One set of solutions is to go with multiple LED light sources and switch them for different luminosity. Another solution might be to use home automation dimmer(s), a timer module, and a dimable LED light source. I prefer UPB over X-10 but I have not tried these dimmers with LED lights yet. There are many options available, but in general I think you will have to "roll your own" to a certain extent.