Flutterby™! : Whines of the weekend 2009-03-30 13:34:45.649531+00

Whines of the weekend

2009-03-30 13:34:45.649531+00 by Dan Lyke 21 comments

Dear Ubuntu upgrade: How about rather than giving me the "close all of your apps to continue" after half an hour of diddling about with my computer, but before an hour and a half to two hours of downloads that precede the actual drop-dead point, you give it to me at the actual "point of no return"? That way I don't walk away from my computer the night before believing that the update will be done in the morning. Or, better yet, how about a "just go and do it, already" checkbox?

Dear Toro ECXTRA irrigation computer software (that I got with the dongle for $12 at Yardbird's going out of business liquidation): Really, Vista has been out for how long?

Dear Windows Vista: I could see dropping compatibility with Windows 3.11, probably even Windows 95, but why should I have to reboot to clear whatever got set when I tried to run the application previously, turn off the firewall, explore the CD, right click on the setup, go into properties, set up XP SP2 compatibility, close properties, do "Run As Administrator", to make this work?

Also, Vista, "The computer rebooted unexpectedly. Diagnose/Cancel" where "Diagnose", so far as I can tell, does nothing, is not a helpful error message. I realize that you have a tendency to "blue screen" occasionally (despite the fact that this is a few month old computer that came with Vista installed), perhaps you could log that somewhere and offer it up as a "more info" dialog when you come back up?

Oh, look, Vista blue-screened again! Funny how I've got Linux running on bizarre hardware where I'm actively pushing the limits of things to see how far I can push it and it's running fine, even when subsystems blow chunks, but a basic Windows box... well... Grrr...

You had recommended Atmel hardware to me at one other time when we discussed hardware to control some of the stuff that I am doing. I acquired a Duemilanove, which was plug n play to my PC, unlike some of the other communications and hardware interfacing I have done in the past -- the ones that left permanent fracture lines in my skull after banging my head against every wall in sight. The Duemilanove options seem pretty flexible., and I already have more than a passing acquaintance with C (though it is not a favorite), so unlike some of the other families, I wouldn't have to learn Java or some microprocessor specific assembler or machine code.

I will have about 8 zones to control for my drip irrigation project. I need RF to go from my home out to the vegetable garden. Then I can use relays to drive some low power latching solenoid valves to control water flow in the pipe system. Distance, lightning potential, rocky soil and a driveway preclude using cable.

I never played with RF communications before. I was thinking about using Xbee -- have you any experience with Xbee? Does it play nicely with the Atmel hardware? Would you suggest that I look into something else?

Intermediate comment, typed in a text browser, 'cause I'm stuck between a system check with new memory on the Windows box (Ubuntu tells me that what was causing some of the issues on the Vista machine was a bad memory stick) and an upgrade on the Ubuntu laptop.

For right now, I've just got the Toro ECXTRA controller, with the Yardbirds sale I kicked it up to ten channels, I've got 8 of them wired up so far, and it's been okay. But I also live in an area where we can predict the weather for 8 months out, and despite local water officials calling the predictions for drought this summer dire, code here (unlike most of the rest of the country) doesn't require rain sensors: Turn irrigation off during during the rainy season, back on in the spring.

The closest I've gotten to wireless with the Atmel controllers has been a bit of playing with the RZRAVEN boards, which are, I think, roughly ZigBee out of the box. Each of their terminal boards has a relay driving output, but I haven't put my own code on one of them yet, only played with sending messages to them via the USB hub.

You probably know this, but the standard for valves is 24v solenoids, and my 10 zone controller has a small wall wart, so they have to draw trivial amounts of current. You could probably drive 'em directly with a 2n2222 and a diode.

I didn't even know Vista could blue-screen until it started happening to me about once a week. Since I do dev work on my computer, I figured it was something I had installed. I started removing multiple updates for things like VSC++, java, and .net and just installed the latest proper version, and then it started blue screening about once a day.

After it moved to three times one day, I downloaded wubi and put ubuntu on here. It basically runs everything I need for work with the exception of Borland Delphi and MS Visual Studio. (working on getting delphi on a xp virtual machine now)

Luckily, even though I'd never gotten Ubuntu on this box to the point where it could run Windows virtualized, when I installed it I got memtestx86, which, after the machine started bluescreening on or shortly after every boot this morning, showed me fairly quickly that I had a bad RAM stick. $70 to Staples later and I'm back running.

I'm gonna revisit this and see if I can either bypass enough of the licensing crap to get my Windows partition running virtualized on the Ubuntu host, or vice-versa. It's funny, the whole reason I started putting Ubuntu on this machine was better hardware support; specifically, Ubuntu deals with my scanner, and my joystick for FlightGear, better.

Looked at the Deumalinove, looks like the little board I built for my Mega16 explorations, except they got all the right support circuitry on the board. Looks like a no-brainer to use 'em for ATMega16 stuff.

And those XBees look sweet! The starter kits look like overkill, and a board which gets the connections to them right might be reason to go with a custom PCB rather than the Deumalinove, but... dang. Don't know if I want to continue mucking about with the RZRAVEN or just buy a couple of those.

I know that what the irrigation industry calls "electronic" is 18-24V. Mine are what are called timer or battery valves which are spec'ed at 6-9Vdc. They are frequently run from 1 or 2 drugstore variety 9V batteries with an electronic timer. Such battery capacity is supposed to last a season.

Don't know exactly what the power requirements are, but I would use a 12V car or deep charge battery. And run them off a power supply, possibly revolving around a 7508. Such a supply is well within my limited hardware capabilities. Just another circuit on the board that powers the Arudino.

I need to add a solar charger for an electric fence anyway as I have serious wildlife issues. Lots of deer, coons, porcupines, skunks, rabbits, etc. So I don't have to add on a major subsystem. They wildlife did a job on my veggies last year when I forgot to renew my homemade deer away mix.

No rush on an answer. I need to get this system up and running manually first, and is about two months before anticipated completion. Target for the automation is later this year, hopefully not next year.

Sorry about your VISTA problems, just remember to wash your hands after you are finished using it, even if you are wearing latex gloves. And for goodness sakes be careful around sharp objects until you do, those pathogens can go right through bloodstream and into the brain. An eyewash and asprin would help too.

There is an XBee shield available too. It allows a couple of different power to XBees to be inserted for differing transmission lengths. The newer series 2 also supports a mesh. This is real plus as I live in a contemporary log, and adding any new cabling around the log faces or support beams is more than a pain. Its only about $80 or so for the Duemilanove and XBee RF setup, maybe $30-40 for a prebuilt relay bank. I can think of a lot of other uses if the primary additional communications cost is only on the order of $80-100 bucks. Ethernet converting shield available too.

The hardware for the garden drip system is $1300, so the add on cost is not bad, Actually about 1/2 of a timer system, and room for more zones at minimal cost as well as some ADC inputs for temps sensors, rain sensor, soil moisture sensors, etc.

Again, thanks for your help. It is really great for me to know that at least I am headed in a reasonable direction in an area I know little about.

Above I should have said that the XBee shield is supposed to made to fit directly on the Duemilanove board.

I need to finish my bike computer so I can justify buying more toys, I think that'd work fine.

And I haven't tried running all 10 valve slots at one time yet, but the wall wart with my irrigation computer is 750mA, 24v. The ATMega168 spec sheet says max of 40mA per pin to the overall current (to, I think, 200mA total), absolute maximum operating voltage is 6v, if they're really substantially lower current you're pretty darned close to be able to just drive the things directly (although by the time you get a diode in there to keep the induction from the solenoid coil from doing damage, that's optimistic).

At the very least you should be able to save current by skipping the relays: A 2N2222 is overkill, but it's cheap and available everywhere and has leads you can solder just on perf board, put a diode from the emitter back to the collector, to protect against the aforementioned induction, it should have a gain between 50 and 100x (depends on voltage between collector and emitter), so a resistor around 2.2k Ohm will let you draw at least 100mA (all numbers are approximate, test this one on a breadboard before you solder it up). And I do actual circuits only when I can't pawn them off on someone else.

And the prefab relay board I have lying around here uses exactly that to feed the relays.

#Comment Re: made: 2009-03-31 00:04:28.494007+00 by: meuon [edit history]

I've got the complete Xbee dev kit.. it looks slick....and no time to get into that mode right now, it's not a paying project. M, are you near Chattanooga? Although I should just ship the whole kit to Dan.

Putting the pieces together, I believe m is in southwestern New York. I can't make a direct commitment to getting to it, but it's getting higher on my list.

Additional giggle on the irrigation computer software: The registration page that the software sends you off to is now owned by a domain squatter. Clearly this wasn't a priority product...

A caveat on the valves - The ones I've used are 24 Vac. Since inductance limits the current in an ac solenoid, they probably will function on considerably lower Voltage dc, and possibly burn out is you hit them with 24 Vdc.

#Comment Re: made: 2009-03-31 14:41:45.277955+00 by: m [edit history]

meuon, Yes, I live in Corning, NY. Along the Pa border, about 50 miles South of Cornell at Ithaca, and about 90 miles west of Binghampton. Thank you for your kindness in thinking of me. But I need to standardize on the latest series of Xbees because of the new mesh capabilities that have been added.

Dan, thanks for the circuit tip. I only want one valve circuit active at a time, and I absolutely will try breadboarding your suggestion when the valves come in. My interest in the zoning is to limit the load put on my well in terms of the total water flow, not maintaining water pressure. I only need about 10lbs of pressure for the inline drip emitters that I will be using. If my well could withstand supplying four or eight zones at a time, I would use easier and cheaper methods of controlling the water delivered to the individual zones.

#Comment Re: made: 2009-03-31 14:43:59.765404+00 by: Dan Lyke [edit history]

Aha! Dad, thanks, it's been so long since I've seen an AC wall wart I didn't pay attention to that... Huh. Now I'm wondering how you build one of those that's efficient; I kind of understand switching power supplies, but there DC is the point.

m, yeah, totally understand the need to limit overall consumption. I'm on a municipal feed with over 90PSI delivered to the house through a 3/4" pipe, so I can probably blow open every valve at once and not see much drop. And my yard is fairly small. But when I was planning the irrigation system, everything started with a "calculate your flow", so I did.

You can drive the AVR at pretty close to 6V (that's supposed to be an absolute upper limit), and your valves probably pull less than 40mA, but as I try to figure out where to feed the induction back from the solenoids (ie: you don't want to just stuff it back on Vcc, lest you do nasty things to the AVR, and the voltage drop across the diodes mean you don't just want to put the diode from the output pin to the input of the solenoid) I'm thinking that some sort of secondary driver is better. I mean, I've done one stepper driver that used a zener diode to try to limit Vcc in case I was doing anything too stupid, and it seemed to work fairly well, but I never stuffed a scope on it to see how badly I was corrupting my input. And a warning on all suggestions electrical: I'm a software guy, and my electronics knowledge doesn't get too far beyond V=I/R and a bit of "whoops, let the smoke out, shouldn't do that again".

My favorite hardware debugging technique! Fortunately the electronics are cheap enough now so that is generally not a significant concern. Not having a back up of the component that lost its magic smoke is more of a pain.

Grin. Yeah, unfortunately I've ended up doing it at least once with what was apparently the only available display of its type on this continent, and I also got a batch of dev kits where the solder apparently wasn't reflowed properly, so several BGA parts were flakey and unfixable, but the flakiness was such that I couldn't be sure I hadn't mucked 'em up 'til we got the vendor to start testing parts there.

We were getting the parts because of a really good relationship with the vendor, but from Digi-Key they're about $700 each, and I've probably had ten or fifteen flow through here in the past two months (on my desk right now: two bad ones and three good ones, the latter with substantial hand-solder modifications).

Oh, two more bits of electronics knowledge: When in doubt, slap another capacitor from Vcc to ground, and crystals can be really sensitive to lead length.

My worst "magic smoke" moment occurred when I was trying to interface an Apple II to an IBM Series I for the purpose of eventually transferring logging data up to an IBM main frame. The RS232 card in the Apple had to be pulled in order to set the DIP switches. I had been up over thirty hours and was kind of foggy, and forgot to power down the Apple on one iteration of "pull the card and change the switches." I didn't see the magic smoke leave the Apple, but it surely escaped from just about every chip on the whole motherboard, never mind the I/O card. Worse, it was my personal Apple.

As for magic smoke moments.. I've let out lots of very expensive special magic smoke...