Controller for simple RGB wallwasher installation

[connollycleary]

I am looking to put together a permanent ceiling mounted "wall-washer" lighting installation in RGB. It is for an outdoor (but sheltered) situation in a school in Ireland.

I am trying to figure out what sort of controller I will need. The functioning will be quite simple:

I want the whole wall to be washed alternatively with green or magenta (ie. blue&red) light; no other setting, and no fading neccesary. I am hoping that the lights will change in reaction to presence, but not flashing back and forth between the two constantly (eg. motion sensor(s) set to a high time delay, switching the lights when someone walks by, then leaving them for a few minutes). The other simple-complication is that I want the colour-switching to be random (not green when people are there and magenta when the space is empty, or visa-versa).

Any advice?

I'm not an expert (I'm a new media artist) but I'm handy enough. Trying to do this cheaply but correctly: I don't think I have the budget (or the patience) for a big DMX controller, but I'm open to suggestions. I'd like it all to be as simple and sturdy as possible.

Thanks in advance.

[alistermorton]

For a one off application like this it might be easier to design an interface to a raspberry pi or arduino type of thing, and write a bit of custom code to react to the inputs from the proximity detector, and send control signals to an LED power supply, rather than try to shoehorn somethnig existing into the aplpication.

[maeterlinck]

+1 for the Pi or Arduino.

 

There are also a number of small controllers that could achieve this with some external bits. Depends on your budget.

 

Do you have the lights already?

[connollycleary]

You might be right.

Whay does every simple thing end up so complex? I was originally thinking of just having a standard light switch that switches between green and red/blue channels of the LED fitments, that anyone can switch when they feel like it. The school principle persuaded me to consider a motion sensor instead of a switch (it's a boys school), and now here I am considering complex electronics for what looked so simple to start with… any opinion on whether I could get the original idea to work with wallwashers? I also thought of a simple circuit using two standard motion-sensor switches at either end of the space, switching between green & red/blue circuits.

Cheers & thanks

 

No, haven't bought anything yet.

+1 for the Pi or Arduino.

 

There are also a number of small controllers that could achieve this with some external bits. Depends on your budget.

 

Do you have the lights already?

 

Budget is small I'm afraid, given that I was hoping to do everything super low-tech… am syphoning money off other parts of the project for this!

+1 for the Pi or Arduino.

 

There are also a number of small controllers that could achieve this with some external bits. Depends on your budget.

 

Do you have the lights already?

[maeterlinck]

If you want only simple control, like On/Off or pre-defined motion reaction then there might be other options for you. LED strip might give you want you need in a simplier / cheaper package.

[musht]

Don`t see why relay logic wouldn`t work, probably need an additional relay to the ones in the PIRs.

[Don Allen]

You could have a motion sensor at either end of the wall. If a person approaches from the left, the sensor turns on the green light and disables the output from the right sensor and starts a timer. After the timer finishes, a movement detected by either detector will turn on it's colour and lock out the other while the timer operates.

 

This will allow some randomness to occur. If a person walks along the wall then lights will change colour. If a person approaches and leaves from the same end, the lights come on and stay that colour. Green from left and magenta from the right.

 

Bit hard to randomise with two colours.

 

Now if you could determine their position along the wall using the two sensors, you could produce their colour position in the colour spectrum. That would be art!

[connollycleary]

When I say random, I simply mean that the wall should not be always green when peole are there, and always magenta when noboby is there.

Thanks!

You could have a motion sensor at either end of the wall. If a person approaches from the left, the sensor turns on the green light and disables the output from the right sensor and starts a timer. After the timer finishes, a movement detected by either detector will turn on it's colour and lock out the other while the timer operates.

 

This will allow some randomness to occur. If a person walks along the wall then lights will change colour. If a person approaches and leaves from the same end, the lights come on and stay that colour. Green from left and magenta from the right.

 

Bit hard to randomise with two colours.

 

Now if you could determine their position along the wall using the two sensors, you could produce their colour position in the colour spectrum. That would be art!

 

Am a little shy of the Arduino/PIR solution. Looking for something more sturdy and simple I think, it being a permanent piece, with very little money. + we're talking about the west of Ireland… anyone who has been there knows what that means!

[callumb]

Arduino are cheap! < £20!

 

Simple logic: PIR detect motion ---> Random number gen ----> spits out 1 or 0 -----> 1=Green, 0=Magenta ----> out to LEDs. Profit.

 

The electronics side of it is simple some Triacs and RGB tape or something like that. Set red and blue channels to HIGH for Magenta and green channel to HIGH for only green. While the inverse is LOW.

 

A Pi is really OTT for this application! o.O

[alistermorton]

I bet the powercontrol shield could be convinced to drive the led tape - triacs would latch on with a DC supply, mosfets would be fine. Something like this: http://www.zagrosrob...aspx?itemid=825

[connollycleary]

Wow, that simple?

Maybe I'll give it a try. If it is that economical, I guess I can build something & test it without breaking the bank…

I could put the arduino above the soffit. Do Arduinos survive the elements well?

 

That looks like it would work!

My main concern now is integrating such a piece of electronics into an external soffit in a secondary school. Would this sort of set up be built to last indefinitely? The architect will probably demand IP rating (at least 44) and I'll have to persuade him that people do this sort of thing all the time.

Thanks for your help.

I bet the powercontrol shield could be convinced to drive the led tape - triacs would latch on with a DC supply, mosfets would be fine. Something like this: http://www.zagrosrob...aspx?itemid=825

[sleah]

Just a couple of thoughts....

Despite the added complication (and speaking as someone who prefer to KISS where possible ;) ) stay away from anykind of switch that needs human intervention. They WILL break it!!! Even if they didn't break it, the novelty will probably wear off and the leds will end up never changing :(

 

I know nothing about programming, but in terms of function it strikes me that whatever does the switching (PIR etc) simply triggers a change of state, rather than a specific state.

The logic being a simple flip-flop. A pulse input that flip-flops the output.

 

As for keeping it locked for an amount of time and making it work with DMX is beyond my brain.... <img src='http://www.blue-room.org.uk/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt=':** laughs out loud **:' />

 

I'm just seeing it as a simple logic circuit.

 

Probably no help at all, I'm just thinking aloud about how I'd try to tackle the problem...

 

Regarding the electronics under the soffit - you can get nice water proof ABS boxes that will be perfect for the job, just search CPC for waterproof enclosures B-)

[musht]

PIR relays in parallel, timer will lock other one out, running relay flip-flop out to changeover relay for power to colours.

 

http://www.emil.matei.ro/onof2.php

 

Arduino`s are great cheap and possibly overkill for the application.

 

Only tubed and solid silicone embedded LED tape has any resistance to mositure, the tubed only stuff seems to trap moisture in.

 

Mebbe these worth a look http://www.bigclive.com/flud.htm

[connollycleary]

Thanks for that!

The school would agree with regard to the schoolboys breaking anything they can get their hands on! I really want to avoid having something complex - like an Arduino or Pi - up there if I can do it with something simple.

The trouble with standard common or garden motion sensor switches is that they are always set to turn the light on and then turn it off again (after a delay). If I could suppress the switch off function, or associate it with a 'flip-flop'/toggle relay of some kind…

As you say: KISS!

 

Just a couple of thoughts....

Despite the added complication (and speaking as someone who prefer to KISS where possible ;) ) stay away from anykind of switch that needs human intervention. They WILL break it!!! Even if they didn't break it, the novelty will probably wear off and the leds will end up never changing :(

 

I know nothing about programming, but in terms of function it strikes me that whatever does the switching (PIR etc) simply triggers a change of state, rather than a specific state.

The logic being a simple flip-flop. A pulse input that flip-flops the output.

 

As for keeping it locked for an amount of time and making it work with DMX is beyond my brain.... <img src='http://www.blue-room.org.uk/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt=':** laughs out loud **:' />

 

I'm just seeing it as a simple logic circuit.

 

Probably no help at all, I'm just thinking aloud about how I'd try to tackle the problem...

 

 

Regarding the electronics under the soffit - you can get nice water proof ABS boxes that will be perfect for the job, just search CPC for waterproof enclosures B-)

 

I will look into sourcing some sort of flip-flop switch. It will need to be super-vandal-resistant, but I think there must be something available.

Thanks!

PIR relays in parallel, timer will lock other one out, running relay flip-flop out to changeover relay for power to colours.

 

http://www.emil.matei.ro/onof2.php

 

Arduino`s are great cheap and possibly overkill for the application.

 

Only tubed and solid silicone embedded LED tape has any resistance to mositure, the tubed only stuff seems to trap moisture in.

 

Mebbe these worth a look http://www.bigclive.com/flud.htm

[alistermorton]

The trouble with standard common or garden motion sensor switches is that they are always set to turn the light on and then turn it off again (after a delay). If I could suppress the switch off function, or associate it with a 'flip-flop'/toggle relay of some kind…

 

What you need to do is get the PIR to start a timer whenever it closes. If it opens before the timer has expired, the lights stay on in their current state until the timer expires. If it re-closes you can arrange for it either to be ignored (the timer is already running), or to reset the timer, so that that lighting stays on until some time after the last trigger. Often the second option is better, as it avoids the immediate retriggering just after the time has expired problem leading to flickering between states.

 

This is classic pulse stretching, usually achieved with some sort of monostable multi-vibrator.