I install HVAC control systems for a living. Almost all of them rely on Windows at some point along the way anymore, either for setup software or the user interface software (if it doesn't use a web interface).

However, most do NOT require the Windows computer in order to function properly. The systems either have a dedicated embedded-style building controller, or use a peer-to-peer arrangement with each device handling its own schedules and talking to each other directly to integrate. It's entirely possible that the most he could actually do from that computer is look at a few temperatures.

Not that I expect that's reality. Unfortunately, we're typically talking about people with very little computer / networking skills, and security is dead last on anyone's mind when setting these systems up. They wouldn't even talk to IT at all if they didn't need an IP or LAN drop somewhere. I try to caution people about the need for at least rudimentary security, but all too often ease-of-use wins the day. Some even have their HVAC systems exposed directly to the net so they can more easily use their smartphones or check on things from home. Combine with braindead username/password selection and I'm surprised many haven't been hacked.

One way I try to prevent total disaster is by careful programming - make it so the user front-end doesn't allow them to do stupid stuff, and sanity-check user input. But there's a limit to what can be done with most of these systems, and in the end if the customer says he wants to be able to do something stupid - well, it's his building. Just don't expect me to cover it under warranty!

Climate control (at least for commercial HVAC) is a relative non-issue as well. Every motor I've seen installed lately is happy at either frequency - for that matter, we put lots of them on variable-speed drives which varies the frequency and voltage all over the place. Only extremely old motors might have issues.

So all that really happens is the motor speeds up/down a bit (depending on who converts their system) which is handily fixed - if you even need to - as most large air handling equipment is belt-driven. Pull the sheaves off, put on a slightly-different size, fire it back up. Some equipment has adjustable sheaves already, so just screw the assembly in/out a bit to change the diameter.

Water pumps aren't so readily adjusted, but most have balancing valves after the pumps anyway to set the desired flow - just tweak it open/closed a bit and again you're done.

Some of the really old building automation systems I've seen used to use "line time clocks" - referencing the AC frequency for their clock. I expect some of those wouldn't keep proper time, and one particular panel simply quit functioning if the frequency fell outside 60 Hz +/- a few tenths (found that out when they stopped running every time the emergency generators were tested). Those panels were obsoleted by the manufacturer quite a few years ago, but there are still a LOT of them installed and operating (in the US anyway). They would have to be upgraded, but it's an easy retrofit to something newer - the new stuff is so much smaller than those old panels you can just gut the old cans and install new with room to spare.

In part, yes, I could use a larger battery bank. It is currently 8 T-105 "golf cart" batteries, which gives 48V x 205AH = 9840Wh if they are completely discharged. Best to keep a lead-acid battery above 50% discharged, so that's just shy of 5kWh. For daily use I don't like to go more than 25% discharged, so 2.5kWh/day. When these are ready to be replaced, I plan to go with L16s which will double my capacity.

But I can only replace that and run the loads simultaneously during the summer. In winter, I'm doing good to get 3kWh/day from the panels. If the loads are left on the inverter during that time I won't get the battery bank fully charged. Summertime no problem, 6kWh easy - long as it isn't a cloudy day.

My fridge uses 1.6kWh/day, so it alone would almost fully consume my available solar power in winter. The LAN and servers "idle" (when my desktop isn't on) at a total of 120W or so, just shy of 3kWh/day. In summer it is my 24x7 load for the solar system, but again in winter I can't count on achieving that each day. Of course, the desktop only adds to that total number, making it worse.

I have written a program to monitor power usage and switch the loads to grid when the battery bank drops to 25% discharged, then back to inverter at 20%. Works well enough, but it means I discharge the battery in the evenings and it sits partially charged overnight. I need to add to that so it senses when the sun is up, and also "anticipates" sunrise by switching over to inverter in the wee hours of the morning - then the battery bank doesn't spend much time in a discharged state before recharge begins.

Or just spend more money on more panels and battery...!

I have the usual collection of small toys - calculator, garden lights, so forth...

And I have around 1200W in solar panels on the roof. One 135W panel supplies my ham radio bench w/ 12V AGM battery. A (cheap, junky, but still functioning) Harbor Freight 45W panel set is used to charge random 12V batteries or maintain the car in the garage. The rest (8 x 135W) are tied to a battery bank and inverter that feeds a dedicated set of circuits in the house. I can in theory run almost anything in the house off that system - the inverter is good for 3600W - although battery and panel capacities do limit me overall.

Absolutely nothing "green" to my motives - I sat in the dark and cold through a multi-day power outage during an ice storm, and have no intention of doing so again. (I also have a generator, but don't want to run it 24x7 to keep the fridge, lights, computers going. The solar system is effectively a big UPS.)

Depends on the system, of course. I'm running a couple of Mac Minis as linux servers, and when they aren't busy (the vast majority of their time) they are drawing only 12-15W. Loaded up maybe 25W. I also have an OpenRD Client ARM board that draws about 7W.

My previous servers were a P4 desktop and P4 PowerEdge (low-end model) which both used about 90W idle and 150W loaded.

The dollar difference in electricity is about $60/year per machine, but more important I wanted to run my network off the small (~800W in panels) solar power system I installed. Dropping from 2.1kWh/day per machine to 360Wh/day made that possible.

Who says they're "on hold"? With a bluetooth headset, or with the iPhone just plug in the earphones w/mic provided with the phone, and you can tap away while continuing the conversation. They certainly won't hear your fingers unless you're trying to bash a hole in the screen.

I never even thought about simultaneous voice/data, until I realized one day that was exactly what I was doing. Talking with a friend, some topic came up and I pulled up the browser to do a search. Sure, if I'm sitting in the office or at home, the computer might be handier but if I'm - say - waiting on someone at a restaurant or client site, the computer isn't convenient and wifi is normally not available. (Few have "free wifi" around here, if they have it at all they have it locked down.)

Now that I'm aware of it, I realized I use that "feature" all the time - it would be annoying not to have it.

Well, you *could* also pass data while in the "digital voice" mode, even alongside a voice conversation. Just at an abysmally slow data rate (~960 bps). So in theory you could "access the net" even with a VHF/UHF rig if the other end was set up appropriately.

I did this once, set up a PPP link between two ID-800s attached to Linux machines. Just for giggles - the data rate is so horribly slow you almost have time to think between keypresses! :)

Normally the data "side channel" is only used for position reporting like APRS, but there are some apps available that let you do a sort of text-messaging with it. Perhaps that's what has them up in arms, don't want to lose any lucrative text-messaging money from the phone company... (Although then again I'm under the impression France / Europe didn't have insane pricing for texting like we do in the US.)

I'm waiting for a couple of ID-1s to show up right now, be interesting to see what sort of range I'll get from 1.2GHz. Never used that band before...

A nifty trick I've seen electricians using on jobsites is to suck on one end of the conduit with a Shop-Vac, tie a piece of paper (or wad of electrical tape) to the end of the pull string, then feed into the other end of the conduit. With any luck, the vacuum will suck your string right on down to the other end in no time!

I was thinking the same thing.

I can't say I've had NONE fail, but the only piece I remember failing was an oddball Toshiba laptop memory card that they happily replaced years after the fact for free. That replacement worked just fine until the laptop was replaced.

More recently I've been buying Kingston USB drives and SDHC cards because they seemed to have the best balance of reviews on Newegg, so obviously not everyone there has had problems. So far all devices have been working just fine.

Now watch, I've probably jinxed myself - I have two Kingston 16GB SDHC cards arriving *today* for my Sheeva Plugs. They'll probably both die fiery deaths, taking the rest of the kit along with them! ;)

Are there actually cell phones out there that behave this way?!? (Just checked mine, it doesn't have anything like that that I could find.) Why in the world would there be a setting where the phone's response to dialing 911 would be such that you couldn't actually use it as a phone and communicate with the call-taker when they answered? That isn't a double-edged sword, that's just plain brain-dead.

You lost me with the far-fetched scenario after that...

I've never understood this argument. (At least as it applies to the US - perhaps other countries offer better deals - like maybe a tax rebate for donations?)

Why would I give just for a tax deduction? Let's say I'm in the 30% tax bracket. I'm going to give some established charity $1,000 to save myself $300 in taxes? How is coming out $700 poorer in that transaction a "win"? Most people I know who use this argument aren't anywhere near the 30% tax bracket either, so the numbers are even worse.

If I want to give for other reasons, that's a nice "benefit" from the govt, and perhaps it would help encourage me to donate a bit more. But as a sole reason to give?

Even worse were the people who got a home mortgage "for the deduction". A friend actually bought a house because his tax preparer said it would "help him on taxes"! At least with charitable giving some good (hopefully) comes of the money spent, instead of just making a bank that much wealthier...

This is exactly why I bought my laser printer. Most months I only print 2-3 pages. On rare occasion I'll print a manual or PDF book.

Bought a Brother HL-5040 for $220 back in October 2003, and I'm *still* using the original toner cartridge! :p Six years now, and I was lucky if inkjet cartridges would last six *months*.

If he wants the thing to run 24x7, he's also going to need a battery, charge controller to keep the battery from getting overcharged, and an inverter to power the PSU (or change out - if possible - to a DC fed PSU). Adding the battery means ongoing maintenance, at the very least replacement every few years.

Unless he's in a very expensive area for electricity, or where he gets huge rebates from the government (like southern California), electric rates are generally so cheap that you will *never* achieve payback on an off-grid solar system.

I know, because I have one! My intent was for power outages, to keep a few things going, so payback wasn't an issue to me. But I calculated it out anyway, and it would take in the neighborhood of 64 years for my system (bought and installed by me, so no labor costs, and catching pretty decent sales as well) to achieve financial payback. That's if *nothing* goes bad, and somehow I doubt the batteries will last that long...

Still a nifty and fun project, though. I now have 540W in solar panels, a 660AH 12V battery bank, and keep my ham shack off-grid along with the office desk (computer, light), cablemodem, router and VoIP adapter. In an outage, I can switch on the Big Inverter and run the fridge. I've had a couple short outages since getting it all put in, and only noticed because some other lights went off.

Or even a nicer one - I have the 1000HE (Atom processor, 160GB HDD) and it runs 10-12W with the screen on. Performs comparably to the Atom "fanless" desktop machine I also have (which won't run more than 1/2 hour without getting hot as a pistol thanks to the lousy chipset, so it now has a fan on the heatsink!) which pulls 25W at idle with NO screen. Both running Ubuntu 9.04. (Of course, the Eee pulls more when it needs to charge the battery - I don't remember what that tops out at.)

I use the Eee as a laptop, but have considered getting another to replace the desktop. It is a server, running on my off-grid solar system, so more than halving my 24x7 power consumption is a tempting idea...

The wattages above are actually DC measurements off my battery bank - the desktop has a DC PSU, the Eee was running through a small inverter.

When I bought the Eee, I thought it was interesting that the unit with solid-state disk listed a *shorter* battery life than the one with the 160GB HDD... I wanted the space anyway, so went with the HDD.

Hey, wow. I stumbled across the SciFi TV show version one night while sitting in a hotel room on a business trip, never saw it again but remember the story well. Didn't know it was based on a book, I'll have to get it now.