Help with LED dimming / control.

[neilhooper]

We have some RGB LED strips that we want to use for effect / mood lighting. When we bought them they came with a basic controller that's OK but not brilliant by any means. I am intending to use Idratek to control them. I have found a suitable three channel dimmer that uses 0-10v to control the dimming and intend to use a QAO to control it.

Taking the Hall and Stairs as an example. What we really want to do is very slowly change the colour of the strip, random colours would be nice but when someone walks in change the strip to all channels on, ie white then back again when presence is no longer detected.

Can anybody tell me if this could be achieved and possibly point me in the right direction on how to set it up in Cortex.

- Neil

[Gumby]

I be interested in the details of your dimmer since I have a similar RGB strip in my study and want to do the same thing.

I've always fancied being able to do interesting things with the color, including using it as an ambient indicator - you know, link colour to your stock portfolio so that it's always red

Actually, it would be nice to link to incoming callerID and change colour depending on a lookup into the directory...

[neilhooper]

This is it
http://www.ltechonline.com/english/p...ng-Driver.html

I've been in touch with them over the last few days and they are happy to supply direct, also to give an idea of price I have found a Hong Kong supplier selling them at £24.99 so I'm hoping that they will be cheaper direct.

[RichardC]

I'm working on the same thing at the moment, my throughts are to get a LED controller but control it via IR (plus I have a spare Idratek IR sender). So that I can send it signals and let it get on with changing colours itself. Also I can send it IR to make it go to a specific colour (preprogrammed)

Alternatively I do have 3 spare 0-10v outputs nearby so this could be an alternative.

I've been working with Toscal on a lighting design for our new kitchen - he has available a RS232 controlled LED dimmer, but I don't think that can be integrated directly into Idratek.

[neilhooper]

I'm working on the same thing at the moment, my throughts are to get a LED controller but control it via IR (plus I have a spare Idratek IR sender). So that I can send it signals and let it get on with changing colours itself. Also I can send it IR to make it go to a specific colour (preprogrammed)

That could be possible but finding an LED controller that is not the "standard" one that is widely available, that I have already got, seems to be very difficult if not impossible. Have you found one ?

I'm wondering if it can be done via a scene or a macro or some other means but as I'm new to this I don't even know if it's possible to do with Cortex. If it is, I just need somebody to point me in the right direction and I'll start digging.

I haven't actually ordered the 0-10v dimmers, amplifiers or the QAO's that I will need yet because I don't want to waste money chasing something that can't be done !!

[Karam]

A way to do this might be by using the concept that Dimmer OFF/ON does not mean 0%/100% but any values that you choose. So what you could do is control the OFF values using a Scene setting object (and latest release of Cortex), i.e. by having a different 'OFF' profile for each LED colour you will get different hues at different times when the lights are 'OFF' in terms of automation. One possible snag is that the time step resolution of the scene object is 15 minutes. Anyhow, that aside you will at least get the desired automation without further messing about since the idea is that when presence is detected (and possibly you may also be using light level as a gating input) this could be made to switch all LEDs to 'ON' level (all the same value to give white) and then when presence not asserted the LEDs would go to their 'OFF' values according to the scene schedule.

But you'd also need a way to turn the lights totally off and this could be done via a button or by the scheduler by first disabling the Scene object and then setting the 'OFF' levels to 0%. Then you need a way to turn back on which would just be a case of re-enabling the Scene object.

Note: I haven't tried any of this and there maybe alternative solutions, but you could try simulate in Cortex without a physical QAO module.

As a matter of more esoteric interest, the QAO and Dimmer modules have an internal profile function which can operate at a standalone module level (Reflex level). This feature allows you to define an arbitrary dynamic profile with finer step resolution (0.1s - 2min). The profile is stored in the module EEprom and could then be triggered to run as one shot or cyclic. We don't have any nice GUI tools to create the profiles so its a bit of a job, but I thought worth mentioning for wider readership since you never know when a particular application might warrant it.

[toscal]

That could be possible but finding an LED controller that is not the "standard" one that is widely available, that I have already got, seems to be very difficult if not impossible. Have you found one ?

What sort of LED controller are you after.

[neilhooper]

What sort of LED controller are you after.

One that does what I said above.



Karam - I've had another thought.

Last night I was having a play with the API.

Let me run this past you.

Using a modified version of the example for VB2005 Express (I've converted it to VB2008 Express) I think that I could send values to the QAO to set the light levels for each channel. Also I could poll whatever I use as presence detection at the same time to check that the lights don't need to change to white and also poll to make sure nobody has over ridden the setting using a switch if either of these is true then don't send any messages to change values but keep polling to see when it is OK to send messages again.

I don't think I've explained it very well but I'm hoping you get my drift. What do you think ?

[Karam]

Neil,

I'm not the expert on the API so my unconsidered response is 'possibly'. As a general comment, since Cortex is often co-ordinating many different points of interaction for an object I'd usually be a bit wary of trying to have both Cortex automation and user defined code trying to access the same objects for fear of conflicts of objective i.e. Cortex wanting the state to be one value whilst the user code wanting something else. Not saying it can't be done just to be careful to think through any possible conflicts. What is the reason for considering the API route? Do you want finer control of the colour changing time steps or something else?

One benefit you might get via the API is that you may be able to write some code to interface to the LED dimmers offered by Toscal (casatech), but obviously these do not have representative objects in Cortex so it would be a case of your API controlling them directly. It may well be possible to set up a virtual dimmer object in Cortex and you translate its states via your API but I'm ranting now ...

[neilhooper]

I'd usually be a bit wary of trying to have both Cortex automation and user defined code trying to access the same objects for fear of conflicts of objective i.e. Cortex wanting the state to be one value whilst the user code wanting something else.

- What I am thinking is that a light is either "on" or "off". In my case my definition for this particular application is that "on" means all three channels of the RGB strip at 100% ie white light, however "off" is a gradual and random fading between different colours. My thought is that a gradual fade would take say 1/2 an hour to get from one colour to the next.

Looking at what I've seen with the API example code I should be able to keep an "eye" on what Cortex is doing with the object(s) that I want to control. So when Cortex switches the light "on" my code will leave the object alone, when Cortex switches it "off" my code will take over again and carry on the colour changing.

At the moment this is all theory as I'm just starting to simulate it in Cortex.