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Soft start / stop for 230v LED trailing edge lights

Discussion in 'LEDs and Optoelectronics' started by hwextreme, Jun 27, 2016.

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  1. hwextreme


    Jun 27, 2016

    I have installed some 230V LED lights in my driveway which are operated via PIR sensor and a timer.

    The timer runs from 9pm through to 1am and feeds through a standard LED Dimmer switch, so that the lights come one dimly, but when movement is detected via a PIR sensor they go to full brightness, I have the switching currently performed with a DPDT relay. But the problem is that the switching is instant and I would like the changes in brightness to be softer.

    The Dimmer switches have soft start, but this only seems to work when they are turned on, and goes from 0 to the desired level, I have tried using two dimmers but the lights momentarily turn off and then slowly turn on to their pre-set level.

    I was wondering if I could use a capacitor or an inrush current limiter to buffer or slow the changes in brightness on the output of the relay
    The problem I see is that the LED's are trailing edge dim-able, and I do not know how this would work and if I could find a capacitor big enough to have any affect with 36w of LED Lights (8 x 4.5w)

    Here is a circuit diagram of the wiring

    Attached Files:

    Last edited: Jun 27, 2016
  2. Sunnysky


    Jul 15, 2016
    Depending on your LED connections (bridge or unipolar) and P/Ns will determine full RMS current. 200mA ICL should be close for 30 sec delay
  3. Bluejets


    Oct 5, 2014
    Have a feeling I've seen this here before.

    At any rate, these LEDs mostly require a certain type of driver to be able to allow dimming.

    Then, the dimmer has to be suited as well.

    Think you will find it's just one of those things you cannot get with the gear you currently
    Last edited: Jul 16, 2016
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