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[on:]

Hello, and sorry for asking stupid questions. (Again) (Having dozens of tabs open and not understanding everything clearly enough just forces me to make this thread. Also I have ADD. Sorry.)

1.) So, in terms of user-friendliness and cost-effectiveness, is Arduino, or an arduino-like board (Nanode, TeensyDuino etc.) really a good way to control stuff over the internet?
Is there a better one, that doesn't cost a hundred times more?

2.) A lot of people seem to be worried about the memory, which makes me worried about it too. See, I'd like to control almost every electronic device (lights, coffee machines, speakers etc.) with my home automation project, whether it is using Arduino or not. But for starters, I only need it to turn those devices on or off, but how many devices can one board handle? I'd also like to know if there are boards that are specifically designed for these kind of projects. Later on, I'd add more functionality to the project.

3.) I've somehow formed this kind of image in my head, that my project mainly consists of three "sections" which I need to figure out before starting; The sketch, the arduino (or a better option) and
what I connect to the Arduino of course (the output and input). Now what bothers me, is that I'm constantly thinking it cannot be that simple.

The way I see it, the actual Duino (be it Arduino or any other) can just set the state of output pins and read the state of input pins you define in the sketch. The sketch itself determines when and where these actions would be performed. Please correct me, I do know I am wrong somewhere, otherwise I would not be asking these questions.

After all these dumb questions, I'll be sure to write a Home Automation for Dummies when I'm done.

Thans in advance,
iDroid

[Reply #1 on:]

ADD only means you get about twice as much done as I do.  I procrastinate.

There are a number of home automation methods and each has a price tag and reliability concerns.  X10 is pretty cheap, but it is horribly unreliable.  This is experience talking here, not me reading the web and forming an opinion.  I have these X10 devices fail all the time.  There are zigbee devices and insteon devices and several others.  To me, these are too expensive.  A light switch will cost about 45 dollars and things seem to go up from there.  I have a tiny amount of experience with a couple of them, but not enough to say how reliable they are.

However, an arduino, an XBee and some custom circuitry could cost you that or more.  The difference being that it will work and you did it.

So, it sort of depends on what your real goal is.  Do you want to automate your house, have and intimate knowledge of how everything works, and do everything yourself?  Or, perhaps the goal is to just get the darn thing automated so you don't have to check the lights before bed.

I've chosen the arduino route because I want to do it myself.  I've found ways of reducing costs using an ardweeny, XBees and a central controller that make it fun.  Also, the devices you build this way have a versatility that something off the shelf can't have.  But, it's a heck of a lot of work.

As to your question about what an arduino can do.  An arduino can do one heck of a lot more than just set a pin state and check a pin state.  Although, in extension, that is one heck of a lot a capability.  It can also measure voltage which means read an analog sensor for temperature, pressure, position, etc.  Using the various libraries it can talk several protocols to other devices to control and monitor them.  I measure the power coming into my house with one and the inside and outside temperature with others.  Using a peripheral, it can communicate with the outside world using several protocols, not just the internet.  It's not the best device for working over the internet, but it can do it.  Using the arduino you can hook to some other device and let it do the comm for you.

Think not in terms of AN arduino, but a network of wired or otherwise connected tiny computers that do many little tasks around the house for you.  One checks the level of light in the bedroom and turns the lights on for you before you go to bed.  Another checks the temperature in the water heater and turns it on in time for your evening bath.  etc.  Think of something you want automated and then just figure out how to do it.  Then later, after a little experience, do it better (reprogram the device). 

[Reply #2 on:]

Thank you

ADD also means that it's hard for me to concentrate on several things at the same time and that I get easily distracted and frustrated.

OFF-TOPIC:

For example, reading a text (tutorial, post, whatever) that has grammar or spelling errors, use of idiomatic abbrevations irrelevant to the subject such as "u", "r", "wtf", "moar", "plz" and so on,
instantly irritates me, because I think English, as the most widely spoken and a very beatiful language, deserves to be respected and used properly. This irritation fires up the neurons and neurotransmitters, that trigger a defensive state in the brain, because I feel my thoughts need to be protected from the influence of others. If and when differences in opinion are confronted, the brain releases the same chemicals that are used to ensure survival in danger. This causes the more primitive part of the brain to interfere with rational thinking and the limbic system, which makes it hard to process an idea, no matter how valuable it is. Even if the threat comes from harmless things (like what I mentioned above) that we could otherwise agree with or relate to. In a defensive state like this, learning and understanding what I am reading becomes very hard.

And I do know that I myself am not perfect in English, but at least I give it the respect it deserves and try to use it properly. Most of the time I have the dictionary ready in another tab.
And I use it alot.

Back to the topic:

I still don't know how many devices the arduino can handle without having a huge delay between requesting an action and the action being performed (Who wants to wait 10 seconds for a light to get on, when you can walk to the switch in that time...). I Just need to know this so I can plan things ahead. For example, at first I'll be using the system in my room only, since I'm underage and living with my parents, but I plan to expand the system. Maybe my mother would let me hook it up to our coffee machine, since the ON-light is broken and we don't have the screwdriver needed to open the case and everyone is too lazy to order one.
So if I'd know that it could handle, say 5 devices, I could figure out the expenses (how many relays I can use per board and so on?).
The hardware page says:

Digital I/O Pins   14 (of which 6 provide PWM output)
Analog Input Pins   6

Does it mean the arduino can handle 14 devices at a time?

Thanks again.
PS. I didn't quadruple check every word in the OFF-TOPIC explanation, so slap me with a fish if it seems illogical.

[Reply #3 on:]

Does it mean the arduino can handle 14 devices at a time?

Assuming you just bought an Arduino Uno and some relays, yes.

However, if you need more than that, there are tons of things you can do to increase the amount of devices you want to control, so to say that the Arduino can only handle so many devices is a bit misleading because it can handle much more with the right shield or other device.

[Reply #4 on:]

Does it mean the arduino can handle 14 devices at a time?

It depends on what you're attaching to it. If you just want to turn relays on and off, it's actually 20 because you can use the Analog pins as digital ones. Some items, such as an LCD may take more pins to operate them. If you need more, you can use external multiplexing hardware, or you can buy a Mega - more memory and more pins.

Compared to the speed that things happen in a house automation environment, the Arduino is phenomenally fast. You should not have any problem with it keeping up if you code correctly. i.e. don't use the delay function for anything more than tiny debounce (or the like) delays.

[Reply #5 on:]

Does it mean the arduino can handle 14 devices at a time?

It depends on what you're attaching to it. If you just want to turn relays on and off, it's actually 20 because you can use the Analog pins as digital ones. Some items, such as an LCD may take more pins to operate them. If you need more, you can use external multiplexing hardware, or you can buy a Mega - more memory and more pins.

Compared to the speed that things happen in a house automation environment, the Arduino is phenomenally fast. You should not have any problem with it keeping up if you code correctly. i.e. don't use the delay function for anything more than tiny debounce (or the like) delays.

Thank you very much. I'll be snoopin around some boards and try to figure out the best options.

[Reply #6 on:]

Below is a home automation forum tha might be of interest.

http://forums.homeseer.com/

[Reply #7 on:]

I'm also currently working on my own home automation project. I'm using the Arduino Mini (Pro) because of its tiny size. They are quite cheap too, so I will have many of them around the house; one per device I want to control. (I find this better than running long cables from a single Arduino to all devices around the house).
Then I'm using either Bluetooth modules or RF1100-232 433MHz RF wireless modules to send and receive serial commands to/from the Arduinos. (I'm actually now moving away from Bluetooth as it is far more unreliable than the RF modules and has shorter range).

Then I have written a Windows application in C# that controls all these devices and keeps current values for each device in memory that can be get and set by a web application (that my friend develops) over IP.

Currently I have temperature and humidity sensors and a 10W RGB LED that I can control remotely. Next thing will be an Arduino controlled relay that will fit inside a ceiling rose that allows me to switch the lamp on and off remotely.

This brings me to what I see as the biggest issue with this project... Power supplies. Since all these devices connect to 240V mains (I don't want to re-cable the whole house....), each of these devices needs its own little power supply. I'm using the smallest I could find (5V "USB chargers") but still, the PSU always takes up the most space in these devices and limits how small they can be made...

[Reply #8 on:]

I have exactly the same problem with my projects.  Even with 110V, it's hard to find power small enough to keep the project tiny.  I have also been using the USB wall warts, but I take them apart and use just the power supply and throw the plastic shell away.  Helps some, but not as small as I like.

[Reply #9 on:]

Yes, I did the same. Removed the shell and put it in a slightly bigger case that houses the PSU, an Arduino Mini and a Bluetooth module or RF1100-232 module. Then there is a DHT11 sensor glued to the outside. The whole thing plugs into a power socket just like a wall PSU. 2 pictures attached. All that hot melt glue is mostly for safety. I didn't want any mains power exposed.... ;-)

What we would need is a very small switch mode PSU, say, the size of a small relay. Does something like this exist?

[Reply #10 on:]

What we would need is a very small switch mode PSU, say, the size of a small relay. Does something like this exist?

I haven't found one yet.  I'm still looking though.  Nice job on the module, and I would have done something similar to secure the power.