I originally posted this over on the AV science forum.

Rant begin:
As more hi tech hardware is becoming self install, why does this industry seem to stonewall the DIYer? If I were to hazard a guess it would appear many of the HA devices out today started life as a security system or extension of one. Not one is open source but instead would prefer to nickel and dime every possible option. Worse yet is some designs appear to have been designed in the 1980s with no incentive to bring modern parts into the mix. Paying for someone to ship me physical ROM IC upgrades is really old school, opening the box and prying out ICs to install an updated OS is so 1980s.

I believe an open source collective effort could result in a very powerful HA system that doesn't need expensive custom vendors specific control panels (iPads) and a team of technicians to do even the most basic functions.

A typical connected family probably has 75% of the gear they need already in their home. A WiFi router, some computers with a web browser. It's figured Apple will have sold 12 Million iPads by the end of 2010, this is an incredible device that could easily be used as a HA / HVAC remote.

I would simply like to see some of the electrical items in the house to be connected, I don't see the need to spend $50k to do it for a typical home. I'm not talking about the monster homes where $50k is a drop in the bucket but for a typical working family home.

I'm an embedded engineer who specializes in microcontrollers so I can build such a device if the demand exists. I'm not a marketer so if I'm wrong I'd like to hear why.
Rant pause:

 

Won't happen until the chinese are READY for it to happen.

 

LOL, no they'll simply copy it when it happens. Home automation and HVAC control can benefit any household but is currently priced out of reach of most.

My problem is there are so many possibilities that it's hard to tell which one would would have the most appeal.

Example:
Which is best?
1. A standalone controller with Ethernet (complex to program?)
2. A smart slave controller with USB (cheap but needs a internet connected host)
3. An embedded Linux box with I/O (expensive)

Two is cheaper and would be the easiest to program but here's the rub: Leaving your PC on to manage it is wasteful and routers or NASs would have to be hacked (this would require the cooperation of the router / NAS manufacture for it to be a success. Computer hardware manufactures churn out model after model to remain competitive and the internal firmware / hardware can really vary even though the unit looks identical on the outside.

I don't want the solution to be another hacker only creation and I would like it to work with any network on any platform.

 

I would think creating an wireless ethernet based interface that has all the functionality of X10 devies, plus more, such as control of thermostats.

It would need to be backwards compatible with X10 to actually get into the Home Automation market, people have a lot invested already in X 10 control systems, so nudging them toward WiFi while keeping compatibility would be best.

X10 is a good idea, but the data rate is poor, and not very secure. It is a start, however.

 

There exists, in Canada at least, regulations that prevent an "unqualified" person from installing a security or HVAC system, and prevent an "uncertified" system from contacting emergency services or accessing mains power. I can understand these laws, but not their inflexibility in allowing those unqualified persons to do the same, followed by inspection.

I've run across several DIY home automation communities in the past few years, though.

 

You're allowed to install your own thermostat, but not modify your existing furnace controller without a gas license in Ontario. As for security systems it's only those that directly dial emergency services that are regulated to my knowledge. If you wanted an alarm system to SMS or email you I'm unaware of any special regulations.

 

So far the closest approximation of my vision and a current HVAC (no Ethernet, HA) controller is the RCS-TR16

It's basically a wall mounted temperature sensor that uses the existing furnace wiring for communications to the controller. The X10 module is an RS232 unit. This is a fairly basic system but consider its potential. Just add Ethernet with an embedded web server...

 

Yes, I've heard the same. Home insurance companies take security systems into account too, though; I imagine they would require some kind of certificate. Are you part of an open HA group?

 

No I'm not part of an open HA group, I'd be happy to join. And a security system is not on the list of what I'm putting together yet... and it will probably require a form of DOC listing.

 

What is DOC listing? Google and WikiP are stumped.

 

iPads may be cheap to you, but here £500 is a lot. I don't actually know that many people with one; and I may be missing something, but I don't get what's so great about a big iPhone. But maybe I'm missing something. Anyway, that's a rant for another day.

I might be missing the point but why not just make it a web page so you can access it from any smart phone?

Use a microcontroller with ethernet and a power line ethernet controller, for example, Maxim has these: http://www.maxim-ic.com/products/powerline/ You could use this to communicate between modules.

Unfortunately this probably wouldn't be X10 compatible (it might even interfere with X10), but who knows? Maybe that could be added.

I had an idea for doing this: also, it would consist of a bit more, adding a DC power bus to the house providing 24V and battery backup using a lithium polymer rechargeable 18V battery, or if required a 12V sealed lead acid "UPS battery". I also considered adding solar panel or wind generator input, which would switch over from mains input if the output was great enough. A unit would sit somewhere hidden in a cupboard to provide power conversion.

The advantage of a 24V bus vs. normal AC mains is it allows for less strict wiring regulations (doesn't count as high voltage); it allows for simpler controller units (no need for additional isolation or transformer/SMPS) and it allows for things like LED lighting to be built with less complexity and higher efficiency (think simple buck converter.) But of course there are many complexities involved in adding a 24V bus to a building of any kind, so these advantages probably aren't worth it.

Either way, it's an interesting project.

 

Well you don't have to have an iPad, just something with a web browser. If you priced out HA touchscreen remote controls they are uber expensive.

I don't plan on building X10 or powerline controllers, they require UL certification and there are already many devices on the market. Almost all have USB or RS232 versions so I'll make sure there are as many RS232 ports as practical.

12V battery backup is worthwhile for alarms but not for HVAC (your furnace won't work without power) but its worth considering.

 

If you look at my avatar, and my blog you will se a project that I did the begining of this year.

I turned my basement into a DC domicile.

Using my drop ceiling, I wired the it for DC.

The only thing in my basement that was AC was the blower motor for the HVAC system. and the ONLY reason I didn't change that to DC was because of the warranty.

It was a great place to live. When ever I had a power outage, I had a shelter with frige, tv, radio, plenty of light, bench, computer, internet.

The computer was a carputer DC system adapted to operate on 24v.

I took a dozen ac/dc wallwart and yanked the trafo out, so I had regulated DC where ever I needed it.

The cree Xlamps are some bright momba-jombas, I tell you what.

It was a great place for a work bench. I used two 400w inverters bought from harbor freight for cases where I needed AC.. like the TV and computer monitor.

The bank of LA batteries ran the place just fine for 12 hours (Not including the A/C)

That is the longest I went with no power.

A friend lost his job and home, so It had to be re-converted to give him a place to live, but It convinced me of 1 thing.

I will add a DC buss and a natural gas buss to the next home I buy/build.

As for the topic..(sorry).. Blueroom, I think that should have been done long ago.

AND, with the 7inch iPad knockoffs all around, im sure a touch-ready 7" screen is quite affordable.

They run android, which is open source and already contain the communications needed. Add a temperature sensor, some custom software, and we are in business.

I have spent many years in the HVAC trade, and have installed my fair share of security systems. I lack experience in Home Automation, but I can learn.

I would like in on this if you decide to make a go of it.

 

Retched, that sounds pretty cool. You used 24V? I actually designed a DC-DC converter unit which output +5V, +12V, +24V, +36V, +48V as well as -12V and -5V (optional, probably not used), but never completed it. It was rated to 270W and ran everything off an 18V LiPo.

Now I think about it, the better solution would have been to use an inverter to generate 230Vac from the 12V battery banks (or whatever power source you like) and then run a computer SMPS off it. An 800W PSU and 1kW inverter could probably run all the lighting and most of the cooling in a modern house, for probably under £200 for the lot, with plenty of room to spare and expand the system. You'd want to run most of the load off the 12V rail due to the lower voltage drop, and have several different rails. Bonus on top of this is you can also run a computer off it at the same time, if you can figure that out and don't mind a short or fault on one of the rails resetting the computer.

 

Yeah. I went 24 volts because I planned ahead.

Actually, the largest draw is the furnace. Heat is gas, but the combustion air fan and the blower are AC.

I could get the same hp/rpm motors in 24vDC packages. Also, many of the projects I had at the time were solar and battery charging. Instead of boosting 12v up to charge a battery, and increasing current, I decided to go larger.

And also, for the same reason that the power company uses higher voltages, transmission.
Even though my longest run was 36 feet, I could use smaller wire at a decent current.

I made 2 buss lines. High power and low power. the high power used 8 gauge wire to handle things like the fridge and the PC.

All the wall wart stuff used the low power line.

I could have done a color coded, or different connectors to differentiate the two, but to save money, I simply made the left side high power and the right side low power.

Easy enough.

There is plenty of high power inverters made for solar and wind that accept 24vDC, so I could find them no problem.

 

Retched: Looking around my house, the only things I need AC for right now without any mods is the furnace and fridge.

Stove is gas. EVERYTHING else uses a SMPS for a lower Voltage DC current to run (Computers, Displays, etc).

Getting the right Voltage to each item, would need a lot of mods to change the SMPS to DC-DC converters, a LOT of mods there.

 

IMO The closed black box controller has got to go. I'm trying to take the mystery out of the HA / HVAC world. That said some folks want it all and are willing to pay for it, that's fine, but wouldn't it be nice to have an HA / HVAC controller for the rest of us. I'm not talking about distributed audio and home theater but basic control of a typical home. ie: lights, thermostat for starters.

What I propose is:

Open source hardware. This is something I can design (of course the more suggestions / feedback I get the better the initial design) and would make the schematics and documentation available to anyone. I've already begun the groundwork and am reviewing a MIPs core MPU with Ethernet, OTG USB, Six serial ports and more on a single inexpensive IC. Throw in a handful of relays and some inputs and you have the heart of an HA / HVAC controller. I'm going to try to keep the target price around $200.

The hardware as of today are a 32bit MIPs microcontroller with
1 10/100 Ethernet
1 USB
6 relays
4 general purpose or opto-isolated inputs
2 RS485 ports
2 RS232 ports expandable to 4 (may include onboard XBee Pro or ZigBee)
1 IR blaster port
1 onboard temperature sensor (freeze sensor)

Open source firmware. Take Linux for example, look what the community can do if source code is available. There are a lot of really smart people out there with ideas far outreaching anything I've envisioned. You want a feature or have a better way to do something now's your chance. The IDE is free and the C compiler has a free academic version available to anyone. The programming hardware is cheap $50 and a bootloader will be part of the programming so the device can be user updated either via Ethernet or USB.

Just like your PC this device can be customized for the application. Firmware could be upgraded, customized or completely rewritten. It's possible even for user programs to be added or a simple interpreter onboard to run inline code.

What it must be is inexpensive, reliable and low power. What I don't want is something chewing through current like a full blown PC, you just don't need that sort of horsepower to turn lights on and off or run the furnace. What's the point in turning off the light when you've got a 300W PC running 24/7

 

Retched: Well maybe in the future a DC bus will be commonplace. An ideal solution would be to use a boost converter to provide a high voltage DC line, maybe around 40V. (Chosen because it is just shy of the 60V high voltage point, and because there are a lot of "42V car" buck converters available.) That way, wires could be smaller.

I was actually originally going to use something like these RC LiPos:

http://cgi.ebay.co.uk/18-5v-5200mAh...sGames_RadioControlled_JN&hash=item3a5a979cf7

About 10 of them for £260 is a lot given that it's only 52Ah and about 1kW, but they are much smaller than lead acids. So it would probably based on lead acid batteries.

 

Blueroom, I like the idea.

I had an awesome X10 / Alarm / Home Automation setup going a while back. It was all controlled by Debian Linux. There are several X10 friendly, and Automation friendly packages out there.

The biggest/ONLY thing you need to do is develop an open ended API to talk to your hardware for all possible functions, through the different interfaces, leaving room for expansion. Once that is published, adding the "blueroom output" would simply be a library call instead of calling the X10 library.

I'll state it again: Your controller needs to have a legacy X10 interface, even if it is the controller (RS232 to line module). The people that will be interested in the newer/better control system have already invested a good deal of money into X10 technology. They can phase out parts as time goes on and more "blueroom" controls are available.

 

One thing is, does X10 interfere with powerline networking or vice versa?

Also, I was thinking that CAN bus would also be an option for connecting multiple devices, if power line networking doesn't work.