The question is what is home automation?

[ericmark]

With an old disabled mother automatic items can really be a boost. The heating is set to come on automatically and the TV set to turn off automatically the oven maintains the temperature set automatically the phone rejects calls with no caller ID automatically, but most of the technology needs user input.

Be it a remote for TV or a remote for web cam most of what is done to assist is not automatic. The curtains may draw without needing to grab the curtain but one manually presses the button or pulls a cord to get it to do the function required.

Even then there is a safety problem. Her chair lift has a wireless remote to drop the leg and to be frank it is rather dangerous as there is nothing to detect anything in it's path. And this is manually lowered by pressing a button on the remote.

I think the idea with cars to have doors auto lock when engine is off and ignition key removed does help. However it is also a pain when you have put the keys down inside the car. My house has an automatic door lock, when we leave and shut the door it requires a key to gain entry again. My father-in-law has a security door with many leavers which mean it is unlikely to be jimmied open but it does not auto lock you need to lift the handle up and manually turn the key.

Since windows are made of glass and an automatic centre punch can remove the glass in seconds what is the point of having a high security door? My automatic one is far better.

I like the idea of when driving home the global positioning on my phone tells it to automatically turn up the central heating ready for when I arrive, and setting the house alarm automatically turns the central heating down, but there has to be a manual over ride if I am visiting my father-in-law next door but one for Christmas dinner I want to be able to manually turn my heating down.

I have worked in large stores where heating was controlled centrally in London for a store in Chester it simply did not work. If outside is a really hot day then store needs to be cool maybe 18°C but outside temperature zero then in store maybe 22°C is more appropriate.

So yes use the Arduino to automatically control temperature using occupancy sensors, but it also needs to read the weather report to see what the temperature will rise to. If likely mid-day temperatures will sore to 26°C then want to keep house cool. Last thing we will want is getting house to 20°C in the morning. So I have a simple thermostat which although automatic I can manually turn down when forecast says it will be a warm day.

 

[unclebob1]

HI Eric,

I'm in the process of designing my own heating controller, using pi's and relays... the main requirement being that if the pi dies/system fails, i can continue to use the heating manually! With any automation, to me if you automate, make sure you know, and the people who may need to use in your absence also know how to manually override! Even better, have a manual override, as well as a function built into your automation which allows for an overide. In my case, i need to program a "holiday" and "party" mode where i can set a number of days/ours where the heating schedule is ignored, and kicks in again at my expected date/time of return. like wise Eventually i'm hoping that i can connect sensors to windows and doors (internal and external) such that if the heating is on, if the window/door is opened and stays open for a preset time, turn off heating and notify me of the conflict...

With automation, there has to be further understanding of the environment and use... else its just a half a$$ job!

 

[ericmark]

I am sure there are manual central heating systems, to have a fire in the middle of a round house is clearly central heating, but not what we consider as central heating.

Anything with a thermostat or timer is by definition an automated system. The system can be expanded to include thermostats in every room the typical TRV, and using a condensating boiler one has little option as one needs to ensure the room thermostats talk to the boiler normally simply by monitoring the return water temperature.

However as we try to extend the automatic control we encounter conflicts between the systems. I for example use a Myson fan assisted radiator fitted around 1984 which with a non condensating boiler works well. To work it has a large flow of water and the thermostat turns on the fan when the room needs heat. However this unit sends hot water back to the boiler which with non condensating is not a problem but with condensating will cause the flame to reduce.

This talking of thermostat to boiler also has problems when using electronic TRV with timers. The theory seems great. Bedroom not used in day so TRV turns off the radiator, and living room not used over night so again the TRV turns off the radiator. However this completely messes up the hand shaking. The boiler often has anti-cycle software built in. What this does is monitor the time taken from hot water leaving the boiler to hot water returning. If all TRV are closed then the time taken will be short, but if all open it will be long. So if short then heat was not required so re-try time extended, if long then heat was required so re-try time shortened. With standard mechanical valves this works well. But with electronic valves with timers built in it gets all messed up.

So instead of simply adding electronic TRV we have to at the same time tap into the boiler electronics and tell the boiler when to re-try which will correspond to an electronic TRV opening. But to do that the boiler manufacturer has to provide an interface to do it with.

I look at Hive and Nest. The idea of monitoring where people who use the house are and turning on the central heating as they get near to the home seems fine. However they don't need to monitor the temperature as this will vary room to room according to timer on TRV all it needs to do is say on or off. If it is going to monitor temperature then it needs to do it in every room the idea of measuring the temperature of the hall and all other rooms will be a percentage of that heat no longer works.

So for central heating there is a massive jump from TRV and condensating boiler to a system with electronic TRV's with timers connected to a central processor which in turn controls the system. There is really no half way except for those using the old non condensating boilers.

I have looked at automation and telemetry a lot to control my mothers house. I have identified just four items which need monitoring. The toilet, the wheel chair, the bed and the easy chair. In essence my mother should occupy one of them all of the time with may be 5 minutes transfer time. So if not occupying one with a 5 minutes grace then she must have fallen and an alarm needs raising.

Seems simple but other than building the system from scratch there seems to be no system on the market place to do the job. The big problem is the telemetry sensors are easy so are timers, but at a reasonable cost getting that info from her house to mine is the real problem.

 

[Lucid]

You asked "What is home automation?" Proper home automation links several subsystems together and takes input from external sources (local sensors and web based data) and combines all of that to work as a complete system. This goes beyond just controlling the heating or automating some door locks. Your idea of reading the data from a weather forecast is along the right lines but only scratches the surface. Much of what's done in the DIY field with Arduino, RPi, X10 and the like isn't there yet. It's still dealing mostly with isolated subsystems rather than dealing with the house and its occupants in a holistic way. Commercial systems from Crestron, Control4, Savant and others offer the sort of level of integrated control but the ticket price is high.

 

[bernardgreen]

It's still dealing mostly with isolated subsystems rather than dealing with the house and its occupants in a holistic way.

"Dealing with the house and it's occupants" has implications of Big Brother ( Orwell's 1984 version ) taking control of all human life. Automation should do what the humans in the house want it to do, it should never decide what is going to happen to the house and as a consequence to the humans in it.

 

[Lucid]

"Dealing with the house and it's occupants" has implications of Big Brother ( Orwell's 1984 version ) taking control of all human life. Automation should do what the humans in the house want it to do, it should never decide what is going to happen to the house and as a consequence to the humans in it.

Is that just a cheap shot to try and score some points?

We have automation in all sorts of areas of life that take decision making out of human hands. If you spend any time in a modern car then you are probably putting your life in the hands of automation each and every time you hit the road. Traction control, ABS, seatbelt pre-tensioners, air bags and now even collision prevention systems; these are all examples of automation systems that deal with the occupants and the decisions they make. Would you really ascribe Orwellian overtones to the modern motoring industry?

If you are scared of home automation turning down the heating or switching off the air-con automatically in response to an outside window or door being left open, or adjusting the maximum brightness of the hall way lights in the wee small hours so as not to dazzle, or turning down the surround system when the phone rings, then are you sure that the home automation forum is really the place for you?

 

[bernardgreen]

If you are scared of home automation turning down the heating or switching off the air-con automatically in response to an outside window or door being left open

There are times when heating and fresh air are needed at the same time. By all means automate to reduce wasted heat but if you go as far as turning off heating simply because a window is open at least make provision for overiding the function. A person who is ill in bed may require both warmth and fresh air.

Noo cheap shot intended.

 

[Lucid]

If you are scared of home automation turning down the heating or switching off the air-con automatically in response to an outside window or door being left open

There are times when heating and fresh air are needed at the same time. By all means automate to reduce wasted heat but if you go as far as turning off heating simply because a window is open at least make provision for overiding the function. A person who is ill in bed may require both warmth and fresh air.

Noo cheap shot intended.

...and a properly planned and executed home automation system would have the option to cater for this. If I may say so, it sounds like your fears are founded on the limitations of low cost DIY solutions. There is a world of solutions where simple things like these kind of exceptions are dealt with as routine, and that's because the designers and manufacturers have past experience of dealing with the same. What's perhaps being overlooked is all of the time when these exceptions do not occur; those every day normal times when the house is just being used.

 

[ericmark]

I have been involved with automation for many years. My field is PLC (programmable logic control) of machines to do anything from producing concrete blocks for washing machines, packing cheese or milk, making smelly things for loos to medical bags and woman's products.

I have both modified existing and written programs from scratch and to get it right first time is rare. OK some tweaks as to set timers but it is easy to miss out some function required. Often I would include a HMI (human machine interface) so the user could alter selected times etc.

However the lap top was my main tool and it seemed never ending adding bits to a program or altering them. My University lecturer claimed he had written PLC programs which ran first time without a hitch, but I was never so lucky. The use of SCARTA does help an I know my son accesses machines from home to work out what has gone wrong.

In the main the lap top helps locate the fault and often it is the sensor or solenoid at fault not software. But without the option to see what the software is trying to do one can be lead astray. One example was a heater to weld plastic. It was not heating up and tests showed reading 0°C so one would think it should be heating. However a crushed cable will also show 0°C so the programmer had written program so if less than 10°C it would not heat.

I know I have many times cheated. When working in BT telephone exchanges it got very hot and I wanted to open the door but the alarm system would not allow it. So I had bits I could use to bypass the alarm and allow door to be opened. Had I been programming the alarm I am sure there would be a way to allow windows and doors to be opened when some one was on site.

I would have many a talk about what it was safe to allow people to do. And this included the problem in getting people to over ride machine safeties in the way I had fiddled a way to open door.

So to the open window with central heating still running.
1) With a heat recovery unit that should not be required anyway. In other word if needed then there is a design fault.
2) Any over ride needs to be one shot only. So once window is closed on re-opening the over ride must no longer be active.
3) There is a cost in providing an over ride.

With many of the new heat recovery units they only have one fan. So they blow air out but rely on the depression in the room to suck in the replacement air. It therefore needs the door to be closed in the room to work as well as the window. Now the older larger units have two fans and will work what ever position the doors and windows are in.

So it would need some option to adapt software for the systems being used. Now altering a PLC program was simple, but with a PIC (Programmable integrated circuit often made by MicroChip) it needs a lot more skill to write the program. The Arduino is about half way between the two.

The big question is if the automation is required. Having a bathroom fan automatically run and wake others in the house is only required if you can't get people to press a timer button to activate fan when required. A simple manual pneumatic timed button is often much better than automated by use of the light.

Having an electric sliding door on a mini bus carrying school children is a big plus for safety. But with adults it's not required. With electric windows in Holland it was found people could not exit the car when it went into canals, in the UK we don't have the canals so not a problem. The same with the house. What may be good with one house could be complete rubbish with another.