I was reading too fast and missed a possible problem with this setup. The oznium unit says it's got a constant power connection and a trigger connection. You're assuming, and you're probably right, that the unit will ramp up if you apply master power and trigger at the same moment.

This won't, however, allow the oznium unit to ramp down. To ramp down, it needs power after the trigger has been removed. This setup removes power and trigger at the same time. If you add a couple of 100,000 mfd capacitors to the supply.... then you might get a half second of ramp down.

Good catch. Let us know how it goes; was merely shooting from the hip...I'm way past science projects like this these days but would be interested in hearing the outcome.

Combine with the LED fader mentioned earlier, under bed kit motion kit, $26
[Link: amazon.com]

It has

What? It won't turn on with deduction, just induction? Not completely logical! Partially logical, though....

Body motion. Snicker.

Is this an exercise to make a simple task into something into an unapproved, over complicated Frankenstein project?

Why not just use a Lutron sensor paired with a wireless dimmer under the bench tied into the receptacle. Magnetic power supply and LED ribbon of your choice (mine would be GM Lighting).

A couple hours, and off the shelf approved to be installed in someones house parts, collect your $1000 and leave.

Brad,
I'm obviously misunderstanding. I see a dimmer listed, but nothing to make it dim up and down. In our setup, we used a DMX controller with a thousand steps and, as I said, the last two dozen or so steps were not dimming, but distinctly different steps of light level.

Wireless sensor and dimmer (Maestro wireless or similar) will automatically fade to on, and fade to off when triggered with various time out periods available.

Doing it that way will also create a flicker upon startup and fadeout on most strips.
So if the customer is okay with that, then is a good, cheap method.

buzz's description will definitely work. There are a couple of caveats.


If the LEDs all turn on at the same voltage, then the only thing you might call flicker would be the LEDs not turning on simultaneously. Wati. I thought about that a bit.

The voltage across the capacitor is increasing gradually. When the LEDs first turn on, they draw current from the cap and that should lower the voltage, perhaps enough for the LEDs to go into a relaxation oscillation mode (look that up). So, yeah, they could flicker.

But I don't see them flickering on the fade to zero. Again, they might not all go off at the same time.

Worse is the effect the resistor will have on your setup. It will always be in series with the LEDs, so there will be a constant voltage drop across it. If your resistor has to be a hundred ohms and the LEDs draw a half amp, once the cap is charged, the resistors will have a voltage drop of 100 x 0.5 = 50 volts! So a 62 volt supply would be needed for 12V LEDs.

Look at your actual product and measure your actual current draw. I think you'll find the resistor and capacitor idea unwieldy. If you amplify your control capability with one transistor, all of this will be much simpler.

I ran across some videos that are useful to this thread, but useful in general to anyone working with LEDs, so I put them in their own thread. It's worth the time to watch these videos: [Link: remotecentral.com]