Home Automation Network

The first project, one that I've wanted to do for a long time, is a home automation network.  I look around the house and I see a bunch of systems that while useful by themselves, could be more useful if they were integrated and could communicate with each other.

 

For example - the security system uses IR sensors all around the house - wouldn't it be good if I could use them to tell if a room was unoccupied, so I could turn off the lights and save some electricity?

 

The plumbing 'network' knows when the kids have been in the shower for too long, wouldn't it be good to sound a warning, and then maybe even cut the hot water off if they go over some limit that I set?

 

The idea of the HA network (like many others before it) is to connect these systems together in a useful way, so that they can interact, and I can control them either automatically, or from anywhere in the house.

 

I have had some limited experience with using X10 to control some lights and applicances by remote control, and from the computer.  Unfortunately the 'WinPlus' line of X10 devices that I picked up from Bunnings, and also was given some stuff from a mate, seems to be particuarly dodgy - and every one of the X10/RF transceivers that I have has since failed.  While X10 itself is a fairly old technology, it should still be a little more reliable than this!

 

Commercial systems such as C-Bus cost an arm and a leg - and while I'm not ruling out the possible use of some C-bus components later in time, it is not a consideration at this point.

 

Switching into systems engineer mode for a while, I have the following high-level requirements

 

Functional

• The network shall provide the capability to monitor environmental conditions (temperature, humidity, light level, air quality throughout the house
• The network shall be capable of operating in degraded mode when some features are unavailable
• The network shall be capable of being operated remotely
• The network shall log routine and exceptional events for later review
• The network shall provide control over sound (music/paging) throughout the house and outside areas
• The network shall provide the following information to household members, by a wall mounted display, audio, or other means:
• Environmental conditions (room temperature, outside temperature, weather forecast)
• Users of the network shall have the capability to define time and/or date alarms for certain events during the day e.g. wakeup, bedtime, chores reminder (take the garbage out)
• The network shall provide for control over lighting
• The network shall provide for control over air conditioning (split system heating/cooling, and evaporative cooling)
• Environmental control shall make recommendations on which system is most appropriate for the current environmental conditions, as well as advising on opening/closing windows/blinds where suitable.
• The network shall provide basic control over room lighting - initial capability is for LED 'night lights'in rooms, to later expand to general room lighting.

 

Non-Functional

• The network shall be efficient - using a minimum of electrical power where possible
• The network shall be cheap - using self-built devices where needed
• The network shall be expandable
• The network shall be reliable
• The network shall be secure from external attack via wired or wireless means
• The system shall be capable of being used with minimal training.

 

Next level down is design, and here are some design goals

• Wired technology is still cheaper than wireless and also solves the problem of how to power everything and not be replacing batteries or putting things on charge all the time.
• Wireless technology is suitable for low data rate period comms such as a remote temperature sensor, water tank level sensor, or for occasional remote control (eg wifi/bluetooth)
• The main bus will use RS485 in a multi-drop mode, and ATMega 8-bit micro controllers for small nodes
• The system will interface to the extant MRX multi-room audio system
• The system will interface to the extant NX8 security system
• The system will use the extant house file server/media centre/mp3 server for high level functions and storage

 

Thats all for now but I will try and turn this into a more structured document and make it available from here for anyone who is interested.

Introduction

Ok - first time I've ever written my own blog so here it goes.

Wikipedia says - a menagerie is a form of keeping common and exotic animals in captivity that preceded the modern Zoological garden.

So my electronic menagerie is a collection of both common and exotic electronic projects that are in various stages of development.

I've recently started to get back into electronics in a small way, as well as my full time job in software, I am now spending some of my spare time developing some small electronic projects at home.  The main reason is  just because I enjoy it, and as an engineer I am always looking for ways to improve the world around me.  The other reason is that it is a good way to broaden my skill set and try to keep current with this new fangled Arduino and ARM stuff that  now brings us ridiculously cheap computing power compared to when I was at uni back in the early 90's.

I have two projects on the go right now, with some level of crossover between them.  I'll write about them in separate posts, and I'll try and post regular updates as they develop.

Steve