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Sensing ambient light to control lamp brightness


ajander

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I want to control the brightness of a lamp based on the ambient light level in the rooml. Can anyone suggest a way to do this?

 

A little background.  I have a translucent painting that I have back-lit with an LED pannel and diffuser. This LED panel is

controlled by a Insteon Ballast Dimmer, and this works great. However, when the room is bright during the day, the

backlight needs to be brighter.  When the room is darker in the evening, it looks really gaudy when the backlight is on too

bright.  So, I would like to automatically adjust the brightness based on the room light level.

 

I have been scouring the forum and there does not seem to be a simple way to get an analog input into an ISY program.

 

I have considered a few options:

1) Use a motion sensor that has a dusk/dawn sensor. The program would have to step through and set difeerent thresholds

on the sensor to figure out the light level (binary search?).

2) Use a z-wave "multi-sensor."  But, from what I have been reading there is no way to get the light level into a ISY program for comparison.

3. Modify a Insteon thermostat with a light sensor replacing the temperature sensor and read that value as an effective temperature.

 

None of these seem particularly simple or elegant solutions.  Any ideas?

 

I am an electrical engineer, so I don't mind doing a bit of hardware.

 

Thanks for any advice.

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Another thought was to use a fortrezz mimo lite

http://www.fortrezz.com/index.php/products/mimolite

with an light sensor connected to the analog input.

Would I be able to make ISY program decisions based

on this value somehow?

Cool unit. Too bad Insteon doesn't have something like that! :(

 

The stat would give a local value, of some sort, readout and  could be battery operated.

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I've spec'd a couple of systems with these guys lately, for automatic dimming of lighting systems in classroom spaces. The users have been quite happy with it. I've been meaning to see if there was any way to tap into this for home purposes, but I just haven't had the means, motive, and opportunity all at the same time yet. I'll throw it out there and see if maybe someone else can figure out if it's possible. (PDF warning)

 

http://www.wattstopper.com/~/media/WattStopper/Documents/PDF/LightSaver-LS-301-Dimming-Photosensor-Cut-Sheet.ashx

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I've spec'd a couple of systems with these guys lately, for automatic dimming of lighting systems in classroom spaces. The users have been quite happy with it. I've been meaning to see if there was any way to tap into this for home purposes, but I just haven't had the means, motive, and opportunity all at the same time yet. I'll throw it out there and see if maybe someone else can figure out if it's possible. (PDF warning)

 

http://www.wattstopper.com/~/media/WattStopper/Documents/PDF/LightSaver-LS-301-Dimming-Photosensor-Cut-Sheet.ashx

That appears to be a nice  light sensor with an analogue voltage out. The hard part is getting the analogue into ISY for massaging.

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That appears to be a nice light sensor with an analogue voltage out. The hard part is getting the analogue into ISY for massaging.

I wonder if the controller would be better to look at then. These sensors are tied to a controller that I believe sends a digital signal to the control boards in the lights.

 

Or maybe hack the ballast controls at the lights? I'm not an EE, so it takes me a while to figure this stuff out.

 

The really slick thing about this system is that all the line voltage stuff is above the ceiling. The switches, which have some similarity to Insteon switches in terms of programming, are low voltage. All you have to do is run cat5 cable to the switch. No conduit or mc needed. Makes remodels cheaper.

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I like the wattstoppp sensor with 0-10V output.    Looks like it connects directly to a dimmable balast.  Only it woud have the opposite result

of what I need in my case (I want to increase the light level when it gets brighter, not dim).

 

The web control board or pi with a sensor like this would give the cleanest software interface, but then I would also have to add a powerline modem or wifi. 

Seems like a lot of hardware just to get a simple analog input......

 

I wish someone would come up with a real analog input that operates natively in insteon.

 

Thanks for all the advice so far.  Keep the ideas coming. 

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I want to control the brightness of a lamp based on the ambient light level in the rooml. Can anyone suggest a way to do this?

...

I have considered a few options:

...

2) Use a z-wave "multi-sensor."  But, from what I have been reading there is no way to get the light level into a ISY program for comparison.

 

In ISY version 4 you can program a few different light levels using only a Z-Wave Aeotec MultiSensor 6. The approach I mentioned in the following thread would work: http://forum.universal-devices.com/topic/16597-ezio2x4-analogue-mode/?p=147062

 

And then with ISY version 5 (if I understand the planned enhancements correctly) you'll have more flexibility to set variable lighting based on the MultiSensor 6 light sensor readings.

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  • 2 weeks later...
  • 1 month later...

Just an update on this project.

 

I did get the Z-Wave Aeotec Multi-Sensor 6.  It works well.

 

Intallation and liking was straight forward. ISY recognized it without any problems.  Now I can get "analog"

light level readings from the room and adjust the backlight intensity accordingly in an ISY program.

 

I also use the motion sensor to determine when to turn on and off the backlight.   I don't use the temperature, humidity and

tamper signals.

 

One problem:  I find that I don't always get the off signal after the motions sensor time out period. As a consequence, the

picture backlight sometimes remains on until I switch it off manually.   I haven't really investigated where the failure is.

Worst case I can put a timeout in a program instead.

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It occurred to me that sacrificing the humidity sensor on a 2441ZTH thermostat for a light dependant resistor could also work for ISY. All temperature functions in the stat would still function and ISY can read the analogue value from the humidistat as light level. Of course, some scaling would be needed.

 

These analogue values have always been the hardest things to get into ISY.

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....

One problem:  I find that I don't always get the off signal after the motions sensor time out period. As a consequence, the

picture backlight sometimes remains on until I switch it off manually.   I haven't really investigated where the failure is.

Worst case I can put a timeout in a program instead.

 

Normally there are both a "Multilevel Sensor" device and a "Motion Sensor" device for the MultiSensor 6. In programs you can monitor for motion using either device and either control or status.

 

Similar to your situation I think I had one case where ISY didn't get a "motion off" so the Motion Sensor device showed On but the Multilevel Sensor device showed 0%. Since then I've mainly been relying on status of the Multilevel Sensor.

 

Following is an example of a normal trace showing changes for the Multilevel Sensor ZW017_1 and Motion Sensor ZW017_155 when motion is sensed and four minutes later when the motion timer expired:

 

Sun 12/06/2015 12:21:08 PM : [     ZW017_1]       ST 100 (uom=51 prec=0)
Sun 12/06/2015 12:21:08 PM : [     ZW017_1]      DON 100 (uom=51 prec=0)
Sun 12/06/2015 12:21:08 PM : [   ZW017_155]       ST 100 (uom=78 prec=0)
Sun 12/06/2015 12:21:08 PM : [   ZW017_155]      DON 100 (uom=78 prec=0)
Sun 12/06/2015 12:25:07 PM : [     ZW017_1]       ST   0 (uom=51 prec=0)
Sun 12/06/2015 12:25:07 PM : [     ZW017_1]      DOF   0 (uom=51 prec=0)
Sun 12/06/2015 12:25:08 PM : [   ZW017_157]      DOF   0 (uom=78 prec=0)
Sun 12/06/2015 12:25:08 PM : [   ZW017_155]       ST   0 (uom=78 prec=0)
Sun 12/06/2015 12:25:08 PM : [   ZW017_155]      DOF   0 (uom=78 prec=0)
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  • 3 weeks later...

It sounds like you have found a good solution so the following is probably moot at this point, but if others are interested In addition to the other solutions presented here, there is also this: http://smartenit.com/product/ezeye/ which is used in conjunction with one of these: http://smartenit.com/product/ezio4o/.

 

The possible advantage could be its calibration to "Human Eye Accuracy" which I think means it is tuned to the range of wavelengths that the human eye sees, or it could be "sales-speak".

 

Again, as others have mentioned, the ISY can only read discrete values.  In this case the analog to digital conversion is done in the ezio4o module.

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