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1  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.
2  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.
3  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.
4  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.
5  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.
</R&R>
6  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.
7  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.

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Unless is some GOTO kind of operation

What do you mean?
8  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.
9  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 digi.com and there are probably other resources like application notes there as well.

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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.



10  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.
http://www.digi.com/pdf/chart_xbee_rf_features.pdf
11  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.
12  Using Arduino / Networking, Protocols, and Devices / Re: Setting up X-bee network in API mode on: August 26, 2014, 03:49:29 pm
I saw a video in which network Co-ordinator is set in API mode and router in AT mode?.Can we have different modes in the same network?

It's a common misconception, but indeed, as @djb_rh said, the interfaces API/AT as well as baud rates can be mixed or matched in any way. The key point to understand is that these only affect the local interface to the module, and the RF link between modules is always the same and is unaffected by choice of mode (API or AT) or baud rate.

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I read that there are different AT command frames to carry out different functions like source routing,remote AT commands etc. Now My question is how to set different command frames?. Should I program in arduino to send those corresponding AT command frames serially through xbee to other xbee I wish to communicate?
 eg:If i want a router to send a data, Should I create a command frame and send it serially from co-ordinator through zigbee so that router receives it and responds accordingly?

Source routing can be a bit hairy, I would recommend avoiding it until you have more experience and are sure that you need it. Indeed there is a frame to cause a remote module to execute AT commands, frame type 0x17.

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If so ,can u show me a small program example to request a data from a router?

I don't happen to have one of those.

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since I am using more than one light sensor, I want to address a particular sensor from co-ordinator and ask it to transmit the data only when I need it. Is it possible to do using AT command? If so, how to do it?

There is a command (1S) to force a sample to be taken, I suppose this could be sent via frame type 0x17. I don't operate my nodes this way, however, so I haven't tried it.

At the risk of repeating myself, the best favor you could do yourself is to learn to use Andrew Rapp's library. Otherwise you will be reinventing several large wheels. Of course maybe you want to roll your own API frames and also interpret them on the other end as an exercise, which is fine, but prepare to spend much more time on that than on the actual problem you're trying to solve.

In any event, API mode is the only way to go in order to really take advantage of the XBees' capabilities. AT mode is only good for trivial and non-critical applications, and is terribly cumbersome to use in any advanced scenario.
13  Using Arduino / Project Guidance / Re: Recommendation for a Simple 2 Line Display on: August 26, 2014, 07:26:33 am
Adafruit's library works with the MCP23008 I/O expander (as used in their backpacks) and FMalpartida's library works with the PCF8574 expander (as used in backpacks from electrofunltd.com), so the libraries are not interchangeable in that regard.

I benchmarked several libraries in native and in I2C mode (MCP23008); results and code are here.
14  Using Arduino / Project Guidance / Re: Recommendation for a Simple 2 Line Display on: August 25, 2014, 10:31:17 pm
These work very well for me, good sale price right now:
http://www.dipmicro.com/store/index.php?act=viewProd&productCode=LCD-1602A-B

I've also used these, they're also fine, interchangeable with the one above and a little less expensive:
http://www.dipmicro.com/store/LCD1602B-GEN

Both work fine with the standard LiquidCrystal library, as well as with some improved versions that are out there. To convert them to I2C, these work well:
http://www.adafruit.com/products/292
15  Using Arduino / Networking, Protocols, and Devices / Re: Xbee sleep mode question on: August 25, 2014, 10:24:17 pm
No clue I'm afraid. The way I read it, an I/O sample should be sent immediately after waking up. Is it possible that the XBee is not really going back to sleep all the time? Not sure if that would account for the varied behavior.

If power consumption is the only concern with adding a microcontroller, I sure wouldn't worry about that. Sleeping the MCU should make its power consumption negligible. But that would be the easy way out smiley-grin maybe it can be made to work with just the XBee.

What about pullups on the sleep pin, D0 and D1, buttons to ground on D0 and D1, and rather than a wake button on the sleep pin, use diodes to form an OR gate. So one diode from the sleep pin to D0 and one from the sleep pin to D1, with the anodes connected to the sleep pin. When either button is pressed, it should wake the XBee, and the I/O sample should show which button was pressed. Just thinking out loud.
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