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31  Using Arduino / Project Guidance / Re: Arduino Cell phone repeater / signal booster on: December 05, 2013, 12:52:56 pm
Main problem with this project idea is you would need formal 'type acceptance' (at least that's what it is called in the US) from the government's RF spectrum manager (again, in the US that's the FCC).  You are talking about transmitting in regulate spectrum.

If the FCC takes notice of your transmitter, they can and usually do issue stiff fines (a Notice of Forfeiture) in the $10,000 range.

The other RF devices you see used with Arduinos or by hobbists in general are in specifically-allocated spectrum for general unlicensed operation.
32  Using Arduino / General Electronics / Re: Single-wire 24VAC input to Arduino on: December 05, 2013, 07:50:05 am
Another way to visual it is fully turning on a faucet and turning it off rapidly.  You get what they call 'water hammer'.  That's the water rushing through the pipe and inertia producing a force that briefly exceeds the nominal water pressure.
33  Using Arduino / General Electronics / Re: Single-wire 24VAC input to Arduino on: December 04, 2013, 07:48:18 pm
The convention for HVAC signalling is (most of the time):

RED - Power (one side of the isolation transformer)
BLU - Common (other side of the isolation transformer
YEL -  Call for cooling (you have none)
WHT - Call for heat (the zone valve)
GRN - Fan relay (but you have no fan)

THESE ARE ALL LOW VOLTAGE, NO USE OF THE MAINS POWER NEUTRAL AT ALL.

The MID400 senses the 24VAC, which is switched on/off in the thermostat onto YEL, WHT and GRN wires for the corresponding signal back to the heating plant.

So  an MID400 could sense between BLU and YEL, BLU and WHT, BLU and GRN (or BLU and RED to detect whether the system is switched off completely)

And yes, you could utilize the spare green wire you have to be the common lead.  Presently you have (irrespective of what colors are in your bundle) WHT and RED connected to your thermostat.  RED going to the thermostat and WHT returning the call for heat.  So you could make the green wire BLU and a MID400 would connect to BLU and WHT.

And I just realized I *assumed* your zone valves are binary on/off devices and not variable-flow, which is a whole 'nuther thing.
34  Using Arduino / General Electronics / Re: Single-wire 24VAC input to Arduino on: December 04, 2013, 06:42:26 pm
John -- that IC won't work.  You don't have AC hot and neutral at the thermostat, you only have hot.  You can't ever directly measure an isolated voltage with only one wire.  The best you can hope for is inductive, but 24vAC control lines are very low-current.  You would have to use a sensitive inductive meter...

Although I would not connect it at the thermostat myself but rather at the furnace, that should be possible anyway.  It is normal to have a 5 or 6 wire 'thermostat cable' in place even when not all conductors are used.  If not a blue 'ground' (actually just one side of the isolation transformer) already there and connected (in mine it is) there's most likely a conductor you can connect up.  That should be true of any house built since the 60's and certainly one that has A/C (OP didn't mention that though and I realize zone valves are a radiant hot water component).

I had to resort to that when I recently added a 24VAC-powered wi-fi thermostat and needed an always-hot 'C' wire as they call it -- I used one of the unused wires in the bundle.
35  Using Arduino / Project Guidance / Re: Yes all i keep getting is Board at COM1 is not available on: December 04, 2013, 05:27:39 pm
Look in the Arduino/drivers folder on your computer (wherever it was you installed the Arduino IDE software).  Install the USB driver in there and you will be able to connect with your Arduino board.
36  Using Arduino / Sensors / Re: Connect a sensor chip on: December 04, 2013, 05:12:11 pm
The most practical way to connect a surface-mount IC to an Arduino is to buy it mounted on a breakout board:

https://www.sparkfun.com/products/11028

But is possible connect without it. Connecting the capacitators on the breadboard an connect the chip with a cable.

The determinator is whether the pins on the chip match up with the board's contact matrix (it probably won't).  It will be much simpler to buy a prototyping board like https://www.sparkfun.com/products/7914 and as Johnwasser alluded, mount a breakout board with the chip on it.  Then attach to the Arduino.
37  Using Arduino / General Electronics / Re: SMD Soldering Training PCBs on: December 04, 2013, 05:03:26 pm
Cool! 

I do NOT miss the days of RubyLith films and exacto knives OR the spray resist and ferric chloride.  Praise be the PCB jobbers.
38  Using Arduino / General Electronics / Re: Single-wire 24VAC input to Arduino on: December 04, 2013, 04:57:13 pm
[
I used some Fairchild MID400 chips, which are designed exactly for this kind of application.  Works great!  They are opto-isolators and can handle up to around 250 VAC on the input side, as I recall.

http://www.fairchildsemi.com/ds/MI/MID400.pdf
That looks great! Probably means ordering it, unless the local (small) RadioShack has them or something equivalent. Which sucks, because I was hoping to be logging data by the weekend (and shipping things to Alaska takes time). Can this be hooked up in series with the line to the zone valve, or do I have to do this in parallel and still have the issue of figuring out how to ground it?

You would connect to the switched side of the thermostat, so the MID400 'sees' 24V whenever the thermostat completes its circuit.  In effect, you are illuminating an LED inside the MID400 and this causes the output side's photosensor to switch the 5V signal.
39  Using Arduino / General Electronics / Re: Single-wire 24VAC input to Arduino on: December 04, 2013, 03:06:20 pm
I used some Fairchild MID400 chips, which are designed exactly for this kind of application.  Works great!  They are opto-isolators and can handle up to around 250 VAC on the input side, as I recall.

http://www.fairchildsemi.com/ds/MI/MID400.pdf

40  Using Arduino / Project Guidance / Re: Something to hold the light bulbs on: December 03, 2013, 09:07:56 pm
You could use the caps from bottled water, toothpaste as 'sockets' or maybe grab up some glass ball Christmas ornaments in a few weeks then they get deeply discounted.
41  Using Arduino / Sensors / Re: Help me..nRF24L01 2.4GHz Radio/Wireless Transceivers on: December 03, 2013, 07:46:06 pm
Could you try reformatting the code with indentedbrackets and putting it in code tags so it's more easily read? 

Now, on to the matter at hand.  There's the radio.printDetails() function which will give some idea of what the radio is doing.  Have a look at that.  If the values printed are mostly zeros or ones, then the radio is clearly not communicating with the Arduino.  That's where I'd start to figure this out.
42  Using Arduino / Microcontrollers / Re: Trying to use avrdude.exe but window closes imediately on: December 03, 2013, 07:41:47 pm
console apps typically will give you that 'help' display when you omit the minimum required (or provide invalid) command line parameters.

So it sounds like you just need to supply the -t option and the name of a configuration file (based on what I see when I tried to run it myself.
43  Using Arduino / Project Guidance / Re: Advice needed to buy an enclosure on: December 03, 2013, 07:35:40 pm
If this is going to be out in plain sight, then maybe something like a jewelry box?

http://www.ebay.com/itm/Chinese-Wood-Handmade-Hollow-Out-Competitive-Products-Jewelry-Box-1pc-Free-sh-/390686399136?pt=LH_DefaultDomain_0&hash=item5af6b95aa0

$10 and pretty swank.
44  Using Arduino / Project Guidance / Re: Arduino Micro green light constantly flashes !help! on: November 29, 2013, 01:35:10 pm
Did you install the USB driver provided with the Arduino IDE?  Sounds like you may not have.

Look in C:\Program Files (x86)\Arduino\drivers (or wherever the equivalent is for your situation)
45  Using Arduino / Microcontrollers / Re: Is this mega2560 a fake? on: November 29, 2013, 09:53:15 am

No, not the infinity logo with the + and - signs --- the big-ass circular gear-like thingy that only partly fits on the back of the board...



Oh, yeah... Guess my excuse is I don't look at the bottom side very often.  smiley-wink
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