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1  Using Arduino / Project Guidance / Re: PCF2127T on: September 27, 2014, 08:31:00 pm
I dont have experience with RTC, but i need one pretty accurate (I found this IC), and where you are refering to change the library,

How accurate do you need?  DS3231/32/34 are some of the more accurate low-priced RTCs, 2ppm.
2  Community / Bar Sport / Re: Lead free solder on: September 23, 2014, 04:57:13 pm
I'm quite willing to believe the EU is a bunch of bureaucrats passing pointless directives just for the sake of it, although proof of that seems mostly anecdotal.

Happens everywhere including of course here in the US. Congress evidently thinks that because it's their job to make the laws, then the more they make, the better. Nothing could be further from the truth. They also like to make laws because then they appear to be actually doing something. But most of the activity at best is worthless; or worse, is counterproductive tampering. Oft times, doing nothing is the best thing.

Regarding lead free solder, a very good question is if it causes a higher level of failures, then what is the environmental impact of not only scrapping more electronic devices, but also of manufacturing replacements. It's a very difficult question, I don't pretend to have the answer, but I'd be surprised if it was even considered, let alone answered, before the lead-free laws were passed.

In a similar vein, the July 2013 issue of IEEE Spectrum asked, "Are Electric Cars Really Green?" This of course raised quite a controversy, but again, it's a very difficult question to answer, if the end-to-end impact is truly considered. IEEE evidently thought that it was an important enough question that it ran it as the cover story.
3  Community / Bar Sport / Re: Lead free solder on: September 23, 2014, 04:37:10 pm
I just got an architect desk lamp and LED bulbs. The bulbs are so heavy that the lamp can only stay at one position, the worst one of course. It stands tall and won't get closer to my desk without toppling over. I am in need of lead bricks.

Sorry, you can't have them, too toxic. You can only have RoHS bricks.
4  Community / Products and Services / Re: MCP79412 Real-Time Clock on: September 23, 2014, 10:12:28 am
I am interfacing Arduino due with MCP79412
I got this error , i configured MCP79412RTC lib also ....

I don’t have a Due, but after a little research, I found that the Arduino Time library is not compatible with the Due.  As you are aware, my library in turn depends on the Time library.

Please have a look at these forum threads:,136843.0.html,136126.0.html

And the library here:

My library relies on data types (time_t, tmElements_t) and functions defined by the Arduino Time library.  I’m afraid it would need to be rewritten to make it compatible with the Due.  Sorry about that.
5  Using Arduino / Microcontrollers / Re: Strange problem w/ ATTiny85 (MOSI/MISO interference) on: September 18, 2014, 05:22:26 pm
Most people do not try to program an ATtiny85 in the target PCB. It is generally plugged into somithing like a TinyISP and then moved to the target board after programming. Why don't you just breadboard the Arduino as ISP UNO - ATtiny85 programming circuit on a small breadboard and upload your sketches in that and then transfer the tiny to the target board. Wouldn't that be much easier that trying to troubleshoot an unusual problem ?

Kinda tough with a SMT device.
6  Community / Bar Sport / Re: 60 capacitors? on: September 17, 2014, 10:31:47 pm
However, being that it's advertised for audio use, the primary purpose is to give audiophiles something to be excited about.  "Look!  Instead of one capacitor, I use 60!  You should hear the improvement in spaciousness, tighter low-end, and effortless highs!"

LOL, I once read a review of a very pricey power cord that the reviewer swore improved the airiness, imaging, liquidity, etc. etc. etc. But I think it was because they had inked the edges of the CDs with a green Sharpie marker to reduce evil stray laser scatter. Or maybe they hadn't embraced CDs yet due to their digital stridency, I forget.
7  Using Arduino / Microcontrollers / Re: Strange problem w/ ATTiny85 (MOSI/MISO interference) on: September 17, 2014, 10:11:00 pm
Debug with through-hole parts on a breadboard? Another alternative, use larger resistors, say between 470Ω and 1K, build one board with those and use that to debug. I have some SMT LEDs that are plenty bright with 1K.
8  Using Arduino / Microcontrollers / Re: Strange problem w/ ATTiny85 (MOSI/MISO interference) on: September 17, 2014, 08:10:36 pm
I've had similar problems a few times. Basically there is more load present than the programmer can drive. One workaround would be to program the MCU before installing the LEDs and their associated current-limiting resistors.

I have a 3V ATtiny85 circuit that drives some ordinary 5mm LEDs through 100Ω resistors, not charlieplexed or anything, and if the batteries aren't fairly fresh, programming will fail.
9  Community / Bar Sport / Re: IE11 on: September 16, 2014, 09:38:01 pm
Finally put Win 8.1 on my desktop. Had been putting it off because the install had failed on my laptop many months back. They sort of forced the issue. OK, I get it. Well mostly.

Anyway it was painful. Lost count of the reboots over at least an hour and a half. Non-functional device drivers once it completed. Tried to deinstall one, then it wanted to reboot again, but it never came back up completely. Once I finally got that all sorted, Firefox, Chrome and IE all had problems rendering certain pages correctly. Turned out to be an incompatibility with Avast "Web Shield". I've only found one site that's affected so far, disabling Web Shield is a reasonable workaround in that case. Not sure whose problem that is.

So it was pretty much a Charlie Foxtrot. Took all day to get productive again. I hate Microsoft more and more every day.
10  Using Arduino / Programming Questions / Re: Writing to EEprom using Wire on interrupt - Arduino freezing on: September 14, 2014, 09:29:54 am

LOL yes I am well aware what a GOTO is, I didn't understand why it was a necessity here.
11  Using Arduino / Programming Questions / Re: Writing to EEprom using Wire on interrupt - Arduino freezing on: September 14, 2014, 06:53:55 am
That would defeat the purpose of using interrupts in the first place.

I don't see why that would be.

Unless is some GOTO kind of operation

What do you mean?
12  Using Arduino / Programming Questions / Re: Writing to EEprom using Wire on interrupt - Arduino freezing on: September 13, 2014, 07:54:08 pm
The arduino freezes when doing this. In fact it does it with any other interrupt, while attempting to use this function
Is there anything stopping me from using the wire library inside an interrupt? if so how shall I overcome this issue?

PS: The function works OK outside the ISR

The Wire library uses interrupts. Interrupts are disabled upon entry to an ISR. Solution: Simply have the ISR set a flag variable (e.g. bool), monitor the variable in the mainline (non-ISR) code and when the flag is set, call the FRAMwrite() function.
13  Using Arduino / Project Guidance / Re: Wireless datalogger ?? on: September 02, 2014, 08:15:32 am
is the xbee a secure method of transmission ? can somebody snoop on the data being transmitted ?

XBees can do 128-bit AES encryption. For details, XBee product manuals can be downloaded from and there are probably other resources like application notes there as well.

i only need the transmitter to be powerful - the rx will only receive data - can you mix a weak and a powerful xbee ?

Even if the data flow at the application level is one-way, the modules still communicate in two directions in order to send acknowledgements and other network overhead. As others have noted, mismatched modules will work, but range will be limited to that of the lower power module.

14  Using Arduino / Project Guidance / Re: Wireless datalogger ?? on: September 01, 2014, 06:19:59 pm
is there a verion of xbee that is powerful and can transmit long distances

The various "pro" models can transmit up to a mile or two.
15  Using Arduino / Networking, Protocols, and Devices / Re: Xbee sleep mode question on: August 26, 2014, 06:04:14 pm
See attached for an idea of what I had in mind. Most of my XBee applications have not used the XBee's I/O capability, I've maybe played with it once or twice. It seems I always have a sensor or something that the XBee isn't capable of communicating directly with. So I let the MCU do the heavy lifting to produce the data, and then the XBee just does the communication.
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