What are your concerns with relays? I have a bunch that I was intending to use for lighting, have you had trouble with them?

Well then there you go!  Making your own might be the least complicated way of doing it!

I haven't had any issues with them but I'm yet to try them with any mains electricity. They're bloody easy to use and very useful though.

I do have concerns around safety, I could be being over cautious but I don't want to fudge something when it comes to mains. So, a list why I don't think relays are ideal for me.

1) Quality of relay - what makes a good relay? How much do properly decent ones cost with all the correct levels of insulation across circuits? Would I trust the ones I've bought from China? Probably not. (would I even be insured if I fit them myself and they caused a fire?)

2) Each relay will need cables running to whatever is controlling it.

3) I want a physical switch as well as being able to remotely control.

4) Switching states. Which carries on from 3... I want to be able to know whether something is on or off, or be able to calculate/work it out. If you use a relay and a physical switch I'm guessing it would need to be done in a similar fashion to having two switches for one light (upstairs/downstairs on stairs etc) which if I've worked the wiring out right you'd very quickly not know whether the relay being on/off would mean the light is on or off because of the use of the physical switch. I think this would make it impossible to turn a light on/off unless you already knew whether it was on or off. That may not seem like an issue but for example if I was out of the house and wanted to turn a light off, I want to be able to issue an "off" command. There could be a chance that the light is already off and I didn't know, with a relay I'd end up turning the light back on.


My current answer to this is LightwaveRF switches. So to answer the above

1) High quality products, much safer, tested etc. More expensive than relays though.

2) Simple to fit, just replaces your normal wall switch. Controlled wirelessly.

3) It is a physical switch that can be remotely controlled.

4) It can be issued with an "on" or an "off" command. So if you want to try and turn something off that is already off it stays off.

That was obviously to you!

Interesting.  Yeah I'm not crazy about having to wire everything up.  I am going to look into these lightwave things in a bit, it might make more sense for me to use them.

Thanks!

There's a number of other RF options out there.

Some that have a bit of a dummy switch which is battery powered and can go anywhere which acts as a remote and the RF received goes above the light fitting in the ceiling. There's even some lightbulbs out there that have it built in.

I wanted to easiest way to fit a remote controlled light and that was two screws and 2 or 3 wires with the LightwaveRF switches.

The switch I ordered should arrive in the next couple of days and I can have a play. Hopefully it does what I want. Or more so, I hope I can get the Arduino talking to it properly!

I have a set of the Phillips Hue bulbs.  Most of the Open Source Automation programs that I've messed with can control them.  But the downside is they are crazy expensive.  I don't think I'll be getting any more but who knows.

The switch I've bought is £25 (~$40) which I do feel is a bit expensive. Equivalents are probably cheaper in the US.

I've seen a bunch for ~$40, that seems to be the norm for them.  I think that's a little steep but it's the going rate!

Can't find the right thread, but this made me think of your temperature logging stuff. Also seems very interesting and has many very cool possibilities if all SD cards can be hacked like this..
http://www.bunniestudios.com/blog/?p=3554

Bet they work for the Feds.

Who /doesn't/ work for the feds?

Definitely interesting. Large memory, high speed (relatively) microprocessor.

And essentially free. No doubt if it gets popular the manufacturers will start looking the bootloader though :-(

But if it's possible to use something like I2C with it it would be amazingly useful.

Definitely, I2C, SPI or even a GPIO pin or two would be very useful.

> No doubt if it gets popular the manufacturers will start looking the bootloader though

The bootloader is already "locked" - you have to send a special sequence to unlock it.

As the article says:
> It's not feasible to indelibly burn a static body of code into on-chip ROM.
> The crux is that a firmware loading and update mechanism is virtually mandatory.

So the functionality has to be there - they can't take it away. They could perhaps start changing the sequence required to enable loading mode, but what would be the benefit to them? It wouldn't increase their profits, and they have no reason to care about a few people hacking SD cards to do more than store stuff. Maybe, if the dodgy/oversized cards being sold are negatively affecting a particular brand's reputation, they might insist on their chip producers doing something... *shrug*

Locled/secured, whatever. Given the potential for malicious use, it could well be in the manufacturers interests to stop people messing with them.

According to the video presentation, the potential for malicious use is somewhat limited by the fact that comms control is led by the host, not the SD card itself.

I hope these Arduinos get here soon, the light switch came last week and is fitted and waiting to be controlled!

I am curious. In what situations will you remotely control your lights? I tried to count the times I wished I didn't have to go over and press a switch on the wall like some sort of schmuck but so far it's none. No times. But I bet people said that about the TV remote, and well, who's a schmuck now? Those potentially-existing people that I bet on, that's who.

Part of buying just one switch is to see how useful it is.

Current ideas are switching between "moods" if I'm watching TV or a film. Once I can control the switch(es) via RPi/Arduino I will easily be able to that through XBMC.

So, I'd pop the living room lights into my Film mode which might be to turn off the big light and switch on a lamp, or turn everything off all together.

Forgetting to turn a light off when you go out and being able to turn it off using your phone.

Being able to set timers for your regular lights.

If you have suitable bulbs you could even have your bedroom light slowly getting brighter like one of those SAD/Light alarms.

No idea whether I'll make use in those ways but they're possibilities.