LED dimmer ...

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  • chris_j_hunter
    Automated Home Legend
    • Dec 2007
    • 1713

    LED dimmer ...

    a spot of banter over on UK_Selfbuild led to the following device for making an LED driver with dimming (for lighting - cupboard, room, whatever - not indicators) :





    the trick being to substitute a link to an Idratek QAO module output for the potentiometer that's shown connected to the REF/ADJ pins ... not sure quite how to do that yet (more homework required), but thought I'd mention this because LED dimming is not easy to come by !
    Last edited by chris_j_hunter; 30 April 2009, 01:30 PM.
    Our self-build - going further with HA...
  • toscal
    Moderator
    • Oct 2005
    • 2061

    #2
    Actually there is possibly a better device on the market. Simpler to wire up and can either be controlled via a potentiometer or via a 0 to 10v signal or via PWM.


    I've just ordered one to play with.
    So will let you know how I get on.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
    Renovation Spain Blog

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    • chris_j_hunter
      Automated Home Legend
      • Dec 2007
      • 1713

      #3
      well done, look forward to hearing how you get on ... we're looking to drive LEDs around the house, ideally with one controller to lots of lamps - most of which will likely be strips, eg:



      which are a bit expensive at the moment, but we'd hope to be able to use something of the sort to give halo effects around various things, to provide lighting for shelves & displays, for reading lights, for under-bed lights, and so-on - the idea being that it would be good with such things to keep not too far off what will inevitably be variable ambient light levels (daylight & artificial), and so help keep the mood, avoid glare, etc ...
      Last edited by chris_j_hunter; 30 April 2009, 04:04 PM.
      Our self-build - going further with HA...

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      • toscal
        Moderator
        • Oct 2005
        • 2061

        #4
        How about some of these, they come in 1m lengths. Are very flexible and may possibly work out cheaper than the 30cm strips. We also do special under cabinet lighting. If you PM me I can email you the details. All work from 12DC. We also do other types of rigid and flexible led lighting.
        Attached Files
        Last edited by toscal; 30 April 2009, 04:34 PM.
        IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
        Renovation Spain Blog

        Comment

        • Paul_B
          Automated Home Legend
          • Jul 2006
          • 608

          #5
          I've ecommended these guys before but once again they ae always my first stop fo anything LED elated:



          How about something like this:



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          • chris_j_hunter
            Automated Home Legend
            • Dec 2007
            • 1713

            #6
            interesting - still frighteningly expensive, though, and the dimmer seems to be by push-button only ... they also say 0-100%, which always makes me wonder !

            hopefully, prices will come down ... suspect we'll be provisioning rather than installing, for the moment !
            Our self-build - going further with HA...

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            • toscal
              Moderator
              • Oct 2005
              • 2061

              #7
              Thats very expensive. We do something very similar cheaper.
              IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
              Renovation Spain Blog

              Comment

              • Karam
                Automated Home Legend
                • Mar 2005
                • 863

                #8
                Originally posted by chris_j_hunter View Post
                the trick being to substitute a link to an Idratek QAO module output for the potentiometer that's shown connected to the REF/ADJ pins ... not sure quite how to do that yet (more homework required), but thought I'd mention this because LED dimming is not easy to come by !
                Chris,

                As far as I can see it is controlled by a voltage value (0-1.25V I think) so perhaps just a voltage divider on the QAO output could do the job. But toscal's Innoline suggestion looks more practical. Haven't looked at costs.

                Or perhaps there is some hinting going on here

                Comment

                • chris_j_hunter
                  Automated Home Legend
                  • Dec 2007
                  • 1713

                  #9
                  Karam -

                  voltage-divider ... was wondering about grounding strategies, since the LEDs would be on separate power-supplies to the QAO ?

                  0-1.25V - looks that to me, too, max' control to max' brightness, and the Recom looks to be 0-4.5V, max' to min' ...

                  hinting - could-be !

                  Maxim or Recom obviously depends on costs, but it would be easy to believe the latter could work-out best ...

                  dedicated module or satellite (to a QAO), possibly making use of the spare pair in the Cat-5e cable (?)

                  wonder if PWM would actually be better than analogue ?

                  either way, LEDs would seem to be here to stay, so dimmers for them would be good, able to operate on groups of lamps !

                  Chris
                  Last edited by chris_j_hunter; 1 May 2009, 08:23 AM. Reason: spelling & afterthought
                  Our self-build - going further with HA...

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                  • toscal
                    Moderator
                    • Oct 2005
                    • 2061

                    #10
                    We about to get a test LED dimmer. (should be arriving early July). This will be for 12V LED lighting, and will have a 0 to 10V input so control via some home automation systems should be possible. It will have a local dimming control and a separate on off switch. Once we get the prototype and have it up and running I will post here with pics etc. It should look similar to a standard mains dimmer.
                    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
                    Renovation Spain Blog

                    Comment

                    • RichardC
                      Automated Home Jr Member
                      • Mar 2009
                      • 29

                      #11
                      Originally posted by toscal View Post
                      We about to get a test LED dimmer. (should be arriving early July). This will be for 12V LED lighting, and will have a 0 to 10V input so control via some home automation systems should be possible. It will have a local dimming control and a separate on off switch. Once we get the prototype and have it up and running I will post here with pics etc. It should look similar to a standard mains dimmer.
                      How did your test go? (Hope I didn't miss this post if you have already posted about this) We are looking at putting LED lighting in several areas, most likely first to be the kitchen as we normally have a light on in this area all the time. I would put several LED strips into place, one hidden behind one of the beams to reflect off the wall, one on top of the kitchen cabinets. One underneath the cabinets over the work surface, this would need additional lighting I think but would look good at night for in-direct lighting when making a cup of tea etc.

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