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766  Using Arduino / Networking, Protocols, and Devices / Re: Xbee and arduino ? on: June 12, 2011, 03:38:59 am
Good point markbee.  I never considered the power eaten up by the LEDs, I was always fascinated by the way they flash.  I'll keep that in mind when I build a solar powered sensor.  Probably put the LEDs in when I'm testing it and take them out before I deploy it for real use.

There's just something cool about flashing lights.....
767  Community / Exhibition / Gallery / Re: Alarm clock from Atmega328 and 7-segment display on: June 12, 2011, 03:19:34 am
I was coordinating my house clocks using a NIS server was down for several hours.  I'm a bit of a nut about having the little machines monitor their own operation and reboot as necessary and when the NIS server went down, I lost my clock because it rebooted at the end of every retry interval.  That prompted me to get a (relatively) cheap GPS module and take time from the satellites.  That is working really, really well.  In my case I provide the time from a single clock over my ethernet network and a XBee broadcast.  That way I can sync devices based on either protocol.  The little GPS module has a RTC in it too so I don't have to be as careful about reboots.

Your clock is a really cool device.  Doing it from the ground up is impressive and fun.  I would have made the cancel button about 100% larger though; my aim is bad in the morning.
768  Using Arduino / Networking, Protocols, and Devices / Re: Using XBee and USB cable at the same time. on: June 12, 2011, 02:55:38 am
I exclusively use series 2 XBees so I don't have anything definitive on the series 1 for you, but I have never, ever made the XBee work reliably connected to the usart ports at the same time I'm using the USB port.  Tried it a couple of times and there were so many complications I just gave it up forever.  I do what you did.  I create a softwareSerial port on two different digital pins and transfer between this and the usart port (digital 0 and 1).

If you only use pins 0 and 1 for the XBee and disconnect the USB it will work fine; just never worked at the same time as the USB for me.

Oh, I don't have any problem with the series 2 devices working the first time I power them up. That is, if I already have a coordinator running somewhere.  The XBee comes configured as a router with DL set to broadcast and it finds the coordinator and just starts working.  However, if I reprogram it, all bets are off.  About 80% of the time the darn things have some problem or other during programming and I lose various items that have to be programmed back.  Now, if I try to bring two of them up and no coordinator already running, they can't talk since there is no coordinator (new ones always arrive as routers).  One of them has to be set up as a coordinator before there's any hope of them working.  For that very reason, my coordinator is in a device that has almost nothing to do.  It just serves as the house coordinator and a simple clock.  That way I always have a coordinator on line.

Net, the solution you arrived at is almost exactly the same one that I arrived at.  Good job.
769  Using Arduino / Networking, Protocols, and Devices / Re: Examples of Xbee code for arduino to arduino communication? on: June 12, 2011, 02:31:08 am
Well, simple it isn't, but I have arduinos talking to arduinos using XBees.  I have a power monitor that sends broadcasts and a display that receives the broadcasts and displays them at another location in the house.  I have these described at my blog.  I also have a centralized controller that both sends and receives from various XBee devices, but it's not on the blog because I'm still deeply involved in the code for this; it'll be up there sometime, but it isn't ready to show off yet.  I also have a pool control device that sends and receives XBee to convert from something I can read to the silly pool controller protocol.

The controller is on a mega 2560 and the code passed the 30K mark over a week ago, so I may never post the code because it is just too darn big.  Anyway, if it helps, feel free to grab anything you want.
770  Using Arduino / Networking, Protocols, and Devices / Re: Xbee and arduino ? on: June 12, 2011, 02:18:43 am
That's a nice looking board, but I couldn't tell if it actually has level conversion for the pins you normally use.  It definitely has a 5 to 3.3 converter, but it doesn't appear to have a level converter for the digital pins.  That would mean that you could still have concerns about signal level on the input being too high and signal level on the output being too low.  Boards like the Adafruit one have a buffer chip that also converts the signal levels for the often used pins. 

When I use a board, I use this one because I can populate it exactly the way I want to use it.  However, the board you linked to has a nice set of leds to help you tell what is going on.

But, remember, even if it doesn't have a buffer for the signal lines it will still work (I have proven that by doing it).  It's just that the objections above related to signal voltages still apply.
771  Using Arduino / Networking, Protocols, and Devices / Re: Xbee and arduino ? on: June 11, 2011, 01:13:46 pm
I have had the same experience as markbee.  I hook the XBee power to the 3.3 volt on the arduino and the tx and rx directly to the arduino digital pins.  It works just fine.  However, if you want to run one of the pro modules, this will not work.  The increased power drain causes problems with the regulator's output (at least for me).  In those cases I get one of the buffer boards and use it with a 5V supply.

But, you can hook it directly to the arduino, power, ground and digital all work just fine.  I have one device that has ran this way for several months without a hiccup.  So, my recommendation is to experiment with it this way (just connect it), and as you get more experience, move to something more sophisticated. 

I hate waiting for stuff to arrive in the mail when I'm trying something new.
772  Using Arduino / Installation & Troubleshooting / Re: Arduino's safe to connect 12v/10A on: June 11, 2011, 11:43:17 am
go to ebay and buy one of those 12 - 5V usb adapters for charging a cell phone.  About 3 bucks or so.  Keep a couple around the house for other things too.  You can easily repurpose these to provide power for most projects.
773  Using Arduino / Networking, Protocols, and Devices / Re: XbeeFaradayCageProblem? on: June 09, 2011, 10:12:30 am
No, that's not a Faraday cage problem.  Sounds more like an extremely electrically noisy environment.  You probably have a ton of rf noise from the various lights and equipment that is making it almost impossible for the XBees to talk.  Take them outside and try it again to be sure.   You should get around 15 to 30 m through normal house walls and such and really good range outside.  If it works outside, you've got extremely high rf noise inside.
774  Community / Bar Sport / Re: Digital illiteracy? on: June 08, 2011, 03:06:47 pm
I worked in IT for a very long time at various positions from programmer to director of programming at one of the fortune 500.  I was totally disillusioned at the corporate handling of people and projects and just wanted out.  I went to school part time and picked up a master's in education and went through all the hoops of testing and such to become a high school teacher.  I was certified in Social Studies, History, Math and General Science, and after some searching, I was offered a job and accepted it to get my feet wet.  I should have known better.

My offer came on the last day before school started and I was assigned to teach 6 classes a day of first year Algebra.  So, no time for preparation, lesson plans or nothing.  No mentor teacher for this first-timer; just toss him in and watch what happens.  I lasted 11 weeks before I gave up.

Why?  Well, the classes were all > 28 students, it was the first year of 'immersion' for Special Needs kids, English immersion for non-English speakers had happened the year before and it was tough to handle it all.  So, when one tries to teach to the smart kids, the less smart get lost and throw their pencils at each other.  When you try to teach to the less smart, the smart ones get bored and throw their pencils at each other.  The ESL (English as a Second Language) students are always lost so they throw their pencils at each other.  There is a minimal dress code so the girls have to hold their backpacks in their laps to keep from showing their panties.  The boys are always trying to get the backpacks away from them.  Cell phones are constantly being used under the desk so it's hard to see.  Ipods are hidden in bras with the cord run under the blouse, under the hair and into the ears to keep them out of sight.  The ESL students set together with the best English speaker trying to translate for them so there is a constant murmur of some foreign language.  To add insult to an already painful job, teachers are constantly required to prove that they are 'Highly Qualified', so teachers are required to attend classes in the evening and on weekends to improve their skills in these situations (no additional pay, this is required).  Each morning from the second week on teachers had to meet with parents of the Special Needs kids to review their progress and problems.

Add to this the problems of curriculum.  The students are required to pass a competency exam; the books don't follow the requirements of the exam so the teachers have to create a curriculum to match the tests.  This means every single day the teacher is standing in front of the copy machine creating worksheets for the next day.  Each teacher is required to match the same curriculum so every teacher is in line waiting their turn.  The students were issued books, but they were never opened; just put in the locker so the school could claim they had books.

I'm not a complainer, so I tried my best to make it work.  I audited the classes of other teachers (long timers), asked for help from the senior teacher on campus who came in and audited my classes.  Followed their suggestions for various ways to improve things, but it wasn't getting much better.  One day I was called to the district office and told that I needed to attend a couple of classes at a local university to upgrade my skills in handling Special Needs kids.  OK, I was fine with that, but when in the day could I make the time?  It seems the district and the school had worked together to create the classes and there was a minimal charge, 25K US dollars for the courses and materials.  I was gone the next week. 

I'm totally retired now (yes, I retired really early) and have given up any thoughts of trying to pass on whatever skills I may have to the next generation.  That chicken-sh*t job in the corporate world wasn't so bad after all.
775  Using Arduino / Project Guidance / Re: Temperature Sensing on a Farm on: June 06, 2011, 10:56:40 am
PaulS made a really good point.  One must make sure to balance the devices since XBees work in pairs at a minimum.  You can construct an unreliable network by not keep close tabs on a nodes range and match it with a device that can receive and transmit to it.  The laser led idea is a good one, but the code to support it is a great deal more complex than just adding a repeater XBee somewhere to pass on data.  Using a laser to communicate is fun, but you get to figure out retries, error detection and correction yourself.  The wire library can help with this if you decide to go that way.
776  Using Arduino / Networking, Protocols, and Devices / Re: Master, Slave, I2C and TinyGPS issues on: June 05, 2011, 06:26:08 pm
That measurement wasn't inside an interrupt routine was it?
777  Using Arduino / Installation & Troubleshooting / Re: Mega 2560 bootloader revised? on: June 05, 2011, 05:44:44 pm
Oh, come on.   There's got to be someone that knows something about this.
778  Using Arduino / Project Guidance / Re: Temperature Sensing on a Farm on: June 04, 2011, 10:13:22 am
I drilled a small hole in the side, ran two wires through and then stuck it to the side with two sided tape.  I was in a hurry to try out the idea.
779  Using Arduino / Networking, Protocols, and Devices / Re: Master, Slave, I2C and TinyGPS issues on: June 01, 2011, 11:29:03 am
Zero milliseconds is unexpected.  I don't have a clue what is going on there; I would have expected something to show up, not much, but something.  I'm not suggesting you try it, but I wonder how long it takes to convert the ascii string from the GPS to a float.  I may have to dig out my device and play a bit.  However, since you get checksum errors and no overflow, I suspect there is something going on that won't be easy to find.  Like you, I'd be thinking about borrowing someone's GPS and comparing results, or adding up the checksums myself to see if the machine is sending them correctly all the time or reviewing tinyGPS's algorithm for calculating the sums, or bumping up the baudrate to shorten character time, or something.

Bet you already did all that.
780  Using Arduino / Installation & Troubleshooting / Mega 2560 bootloader revised? on: June 01, 2011, 11:10:40 am
I have a 2560 that exhibits the bootloader problems discussed in various places.  Three exclamation points cause the load to fail and the watchdog timer doesn't work right.

Is there a new bootloader yet?  I've seen discussions about various fixes, but nothing about a loader being ready.  Yes, I could hunt down the various fixes and try to build a bootloader and then a day later the 'official' one would be announced.  I would much rather keep with the one other folks are using than do something myself and branch off from everyone else.
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