Hall Light Automation

The objectives of this project are:

  • To automate the main ceiling light in our entrance hall, using a schedule to make our home look occupied and improve security.
  • To schedule the light so that it only comes on when it is dark, as determined by our Home Control System (HCS) twilight sensor.
  • To use detected occupancy & presence, to switch the light on when required, improving safety and convenience.

  • To save significant amounts of electrical energy by reducing the power used by this light fitting and optimising its use.

We had previously installed a decorative light on the ceiling of entrance hall, covering the existing ceiling rose. There is a real shortage of attractive lights that have the required low profile. In retrospect, this one was a bit of a mistake because it has ten 10W halogen G4 bulbs and uses 100W when on. We replaced seven of the bulbs with cheap LED equivalents but they were very dim.

We looked at a number of wired solutions to automating this light but there are no easy options, given it's location and the complexity of the existing wires installed. For these reasons we decided to go down the wireless route, using Z-Wave technology.

Design

Lighting Options

Existing light fitting
With ten 10W G4 bulbs, the existing ceiling light took far to much power, especially considering the amount of time this light is in use. It is a central light in the house and is in the main corridor in to the house and through it to the upstairs room. It is also the first light seen on entering the house and lights up the whole hall and stairs. To reduce power usage, we replaced all but three of the ten G4 halogen bulbs with cheap G4 LED equivalents. This still left it using over 30W of power though and with noticeably less light output. It simply didn't look as impressive.

Existing LED bulbs
These are the existing LED bulbs we were using. They are basically just 10mm LEDs with some simple electronics in the white housing. They are rated at 12V / 0.3W and on a 12dc power supply are OK in terms of light output. The problem comes when used with the 12Vac transformer built into the above light fitting. They seem to be much dimmer and we think this is down to a large voltage drop across the rectifier diodes in these bulbs.

Philips G4 LED
This Philips G4 LED bulb is rated at 12V and 2.5W, with 100 lumen output. The colour temperature is 3000K and it has a claimed lifetime of 35,000 hours. These bulbs also come with a 3 year guarantee. This bulb has a 360º lens, making it a true alternative to its halogen equivalent. It is expensive (cheapest price we have found is about £15 delivered. These bulbs are 49.8mm long and 18.7mm in diameter.

There is a 1W version of this bulb, with 50 lumen output and a lifetime of 25,000 hours. There are also 'very warm white' versions with a colour temperature of 2700K. Of all the bulbs we have seen, this is one of the best looking.

Osram G4 LED
The Osram LED Star Pin G4 12V bulb is rated at 1.5W and 12V, with 80 lumen output. The colour temperature is 3000K and a claimed lifetime of 'up to' 15,000 hours. Including the pins it is quite long at 55mm and not as attractive to look at as the Philips equivalent above. It is not dimmable.

Megaman G4 LED
This Megaman G4 LED bulb is rated at 12V and 2W, with 140 lumen output. The colour temperature is 3000K and it has a claimed lifetime of 50,000 hours.

eBay G4 LED
We found these compact 12V ac bulbs on eBay. They are rated at 1.5W and have a reasonable light output. These bulbs were just 99p each delivered!

Lighting Choice

We decided to bite the bullet and buy 10 Philips G4 bulbs. They should save a lot of electricity and last a very long time. Ten of these bulbs (cost approximately £160 delivered) mean the light will provide plenty of light and use 25W of power. This is still more than we would like but, the Fibaro dimmer module needs a minimum load and this project also aims to optimise the time this light is on.

Bulb size comparison
Unfortunately, when these Philips bulbs arrived, we realised that they are a lot bigger than their halogen equivalents. Too big to install into our light fitting in some places. We have had to return these lamps.

We are currently looking at other brands of G4 LED bulbs. In the mean time we have resorted to 5W frosted halogen G4 bulbs. We are going to need to use some of these anyway as the Fibaro module needs a minimum 25W load.

Switch

Kingshield Timer switch
To provide some basic automation, we installed a Kingshield timer switch about 5 or 6 years ago. This is a simple 7-day timer switch with a manual push switch over-ride. Because of the age of our current house, this is wired up without a neutral wire. The problem with these type of timer switches is that they don't handle the change over to British Summer Time and they have no visibility of how light or dark it is outside. This means that you are forever playing with the timings, to optimise the times they switch the light on and off.

MK K3231 face plate
In keeping with our Smart Home philosophy, we also want to maintain a simple and intuitive manual user interface. We have standardised on MK switches and we are using a momentary action switch to toggle this light on and off.

Z-Wave Module

Fibaro FGD211 module
The plan is to replace this existing timer switch with a Fibaro FGD211 module (PDF datasheet), to enable control from our Home Control System (HCS) using Z-Wave. This device is capable of both acting as a dimmer and as a switch. Our light is not capable of being used with a dimmer, so we are using this device for binary switching only.

We are using this device because it is the only Z-Wave module available on the market capable of controlling LED lighting or fluorescent lights in electrical systems without a neutral wire.

Fibaro Dimmer module rating is 500W or 1.8A maximum, when used with non-resistive loads. There is a 'bypass' device but, this is not usually required. It is designed for use with lamps that provide a very low load (~5W or less). With a two-wire installation (no neutral) you need to use the bypass device if the load is below 25VA. As we are borderline with our 25W load, we have bought one just in case.

Sensors

There will be four sensors used to detect presence and extend the time this light is on:

  • Front Door - Also currently a Z-Wave contact sensor.
  • Entrance Hall PIR
  • Lounge Door - a wired contact sensor.
  • Kitchen Door - a wired contact sensor.

Configuration

Warning - Projects like this involve installing and connecting devices to the mains wiring. This is 230Vac in the UK and it can kill you. If you are not qualified or comfortable doing this, then employ a qualified electrician to do the work for you.

Before we installed this equipment and wired it all up, we mounted the Fibaro module, switch and a test load onto a 'test board', which we could plug into a mains power socket. This means we could test it and perform Z-Wave inclusion and configuration in a location next to our Z-Wave controller.

Z-Wave add device
We started up the VeraLite web interface in a browser and under the 'Devices' tab, we chose to 'Add Devices'.

Z-Wave include device
We then chose 'option 1', to include a device in proximity to the controller. This is why we put the Fibaro module and other components on a test board to start with.

Z-Wave new node found
We then plugged it in and a new node (number 11) was found.

Assign name
We then assigned a name and room to this device.

New device found
Finally we have a new device visible in the Vera web interface which can be controlled and dimmed as expected.

At this point we noticed two problems:

  1. Firstly, the filament light bulb we were using to test with wouldn't switch completely off. A quick check showed why. We had picked up a 12W 'night light' bulb by mistake from our bulb store. Swapping this with a 40W bulb resulted in a bulb that switched off properly.
  2. Pressing our momentary action switch quickly would toggle the light on and off as expected. Pressing and holding the switch would cause it to brighten (if it was off) and dim (if it was on). It also remembered previous brightness levels set when toggled quickly on and off. We need to disable this dimming capability.

Fibaro FGD211 Parameters

The Fibaro module has a number of parameters which can be modified in the VeraLite web interface.

Fibaro settings
The settings are accessed by clicking on the spanner icon in the devices view. This pops up a window with a number of device options.

Parameter 10 is the time taken to move the dimmer between the highest and lowest brightness settings (these can be constrained using other parameters). Setting it to 0 should stop the dimmer feature altogether and is required for devices like ours that don't support dimming. This didn't appear to work for us though. It would still dim on pressing and holding the switch.

Parameter 11 is the percentage of dimming step when using the switch (manual control) and has a default value of 1. We tried setting this to its highest value of 99 and this disabled the manual dimming. It would now jump between off and full on and on an full off, when pressing and holding the switch. We still see the bulb not quite switching full off occasionally though. For now this is set back to its default value of 1.

Parameter 14 is set to 1 to configure it for a bi-stable switch or 0 for a mono-stable switch (which is what we are using). The default value is 0.

Parameter 15 is the double click option to set the lighting to 100% brightness. The default value for this is 1 (enabled) and we set it to 0 (disabled). Double clicking the switch simply switches if on and off again quickly now, as expected.

Installation

Installed module behind switch
With it all working pretty much as we wanted on our test board, we then installed the Fibaro module and MK Grid switch in place of the current timer switch. It all fitted into the 25mm deep wall box without any problems.

We then went into the VeraLite UI and in the 'Devices' tab / Settings (spanner icon) / 'Device Options' tab, we then 'Update Neighbour Nodes'.

Automation

Automating this lamp is now simply a matter of updating the main XML configuration file and our 'Entrance Hall' zone, to create a new controller and to also add a new XML configuration file for this controller.

Vera Mobile iOS App

Vera Mobile app view
This is the view of the device as viewed in the Vera Mobile app on our iPhone 5. We don't use this app to control our lighting! It is useful for testing though.

Summary

Not quite sure why we don't get the required behaviour from the Fibaro FGD211 module. Investigating further.

This project is now operational in our house. We have swapped the timer switch over for the Fibaro module and the MK Grid switch. It is now under full control of our . My wife commented that the MK Grid switch feels too stiff in operation but, I reminded her that once all the sensors are linked, she should never have to touch it. The lamp should just know when it needs to be on. This is a real example of zero-touch home automation. Our networked doors project will complete the required set of sensors needed for this project.

It would be very simple to have sensors in other rooms extend the duration that this lamp is on, such that any movement downstairs in our house would keep the light active. My current preference though is to have it go off at the set times and to then come on when people enter the hallway. This approach is more energy efficient.

In our next house the light switches on the walls will simply be a manual, redundant backup, with all of the lighting intelligently automated in this way. It will just know when it needs to be on.

Updates

March 2013

This is now working really well. The controller has been programmed to turn on the light for 2 minutes (if off), when the front door is opened, which is handy when I get back late from the pub :-)

As predicted, the manual switch is just not used now. The light comes on automatically when needed and goes off when it isn't. It is now also linked into a 'good night' scene, which also switches it off. The only thing to be added now is a 1 minute delay on the lounge door opening.

Further Reading

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