Room Management System – putting it together

Assembling options for the controller

Being at that stage, the whole thing has to come of the breadboard. There we also have a couple of options.

1. Keeping the Arduino board
   Advantage of keeping the complete Arduino board is you keep the possibility to connect the system straight to a computer and do quick changes in the settings part and if something goes wrong, to change the board should not take longer than 5 minutes.
   Adding to the Arduino board 2 inexpensive relay shields containing 8 relays each and a 7.5 Volt power supply. That leaves us with putting just the shift register circuits, the LED's if you opt to keep them as indicators, the maintenance switch and the potentiometer to adjust the sensitivity of the photocell.
   The following image is showing a possibility how to connect everything together. Please be advised, that the boards are generic and the connections may vary depending on the relay shields used and how you design the PCB for the controller.

2. Putting the Atmega chip on to the controller PCB with 5 Volt stabilised DC power supply
   This version would compact the the whole system a little but makes it little more complicated to change things. Using this option you have to take the chip out, put it back on a Arduino board to change some of the variables like timings and sensitivities.
   Again, the following image is showing a possibility how to connect everything together. Please be advised, that the boards are generic and the connections may vary depending on the relay shields used and how you design the PCB for the controller.

3. Putting the Atmega chip on to the controller PCB with 7.5 Volt DC power supply
   It is pretty much the same layout as under point 2 except for the supply circuit.
   Again, the following image is showing a possibility how to connect everything together. Please be advised, that the boards are generic and the connections may vary depending on the relay shields used and how you design the PCB for the controller.

Connecting it to your light circuits

Sorry for that but again a little warning before I start:

Connecting the controller to your light circuit means you are dealing with 240 V AC circuits (Europe) and 110 V AC circuits (US). Before you attempt of doing any work on house installations make sure your circuit breakers are off and you double checked with a meter that the part you are working is surely powerless. If you have any doubts in what you are doing you might consider calling a qualified electrician to do the job for you. Working on house installations without the necessary safety precaution can lead to serious injury or death.

OK, lets have a look into connecting the buttons and PIR's first. If followed the line in how I connected everything up on the breadboard and the output relays are addressed accordingly, it is pretty straight forward.

Starting with PIR's:

I had in mind using PIR's with their own power supply to be connected to a common household socket outlet or if it's a new installation it may be a consideration on hard-wire them to a MCB in the main distribution box. On side of the switch of the PIR goes to the common pos connection of the controller input and the other side of the switch to the representing input (e.g. input 1 for room 1 PIR). Depending on size and shape of the room you may need to connect multiple PIR's in parallel to control a bigger area or a room with various corners and niches. The same goes for the switches (momentary switch) to activate or deactivate the priority options in bedrooms and the living area. They are also connected to with one side to the common pos connection of the controller and to the respective input (e.g. input 2 for priority switches of room 1). If needed also priority switches can be connected in parallel. To connect the AC units please check with the user manual of the AC manufacturer. In general you can just use the connection where the readswitches connect to and connect it to the representing relays of the controller since the read switches again are connected to the controllers input in the same way as all the other switches, one contact to common pos and the other one to the representing controller input. The same accounts for the main door read switch. To place the photocell might need some careful observation of the controlled rooms for a few days to determine the right place for it. It should be placed on an average lit place of the controlled rooms to make the lights come on also at dusk or dawn while it's still bright next to the window but the average room starts to get dark. You also may want the maintenance switch to come of the board and somewhere accessible depending on where the controller is installed.

Finally connecting the lights. This takes a little more planing since we want to split off the main lights and the lights additionally controlled by a switch like bed side lights, light in wardrobes or the ones you use just for watching TV. If unmaintained emergency lights are present or the socket outlets where a cordless phone is connected to, a wireless router or a networked TV should stay on a permanent power supply. If you have gas detectors and other alarm systems running of the rooms power supply, make sure that they are not effected by the controller.

The main lights should connect coming from a MCB rated slightly lower than the switch rating of the used relay to the common connector and from the relays NO connector to the lights. If you use only 3 A rated relays you have to add solid state relays and control the solid state relays with relays of our room management controller. The advantage of using separate solid state relays to switch the load is that we can use low DC voltage in the controller. The downside on doing so are the costs.

To connect the maintained lights we do need the help of at least 1 contactor. If you are thinking of cutting also the power to kitchen appliances when nobody is in the room there have to be a minimum of 2 contactors installed. The control circuit for the contactors is coming again from a MCB from the rooms distribution to the coils of the contactors and back to the neutral of the rooms distribution. If you use like a 4 pole contactor you can use every single pole to switch a separate circuit. Again, the line coming from a MCB through 1 of the contactor switches to the lights, socket outlets etc. Another way might be of grouping circuits in the rooms distribution and instead of switching single circuits, cutting off a group of circuits. However, this has to be carefully checked with the load to be switched and the contactor ratings.

The following diagram is showing an example of switching single circuits through the contactor.

Another possible way of connecting it together is shown in the following image