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1  Using Arduino / Installation & Troubleshooting / Re: Opening Serial Monitor Restarts Sketch On Nano. IS THIS NORMAL?? on: Today at 08:54:16 pm
That is normal behavior.  It is the auto-reset feature that allows you to upload sketches without pressing the reset button.
2  Using Arduino / Sensors / Re: Measuring angle using gyroscope on: Today at 08:52:25 pm
Code:
dt = (now  - lastTime ) /1000

That line is missing the closing semicolon so it won't compile. 

Dividing a small integer (now - lastTime) by 1000 is likely to result in the value 0.  You should, therefore, not do the division here.
3  Using Arduino / Project Guidance / Re: Upload Binary from arduino? on: Today at 08:46:58 pm
The program 'avrdude' which the Arduino IDE uses to upload your sketch can also download from the ATmega memory.  I think the Arduino bootloader supports reading (so the upload can be verified) so you should be able to run avrdude in a command window and get it to download the memory contents.  Hopefully it can download it in .hex format for later upload.
4  Using Arduino / Sensors / Re: Measuring angle using gyroscope on: Today at 08:20:42 pm
I don't see the 'dt' calculation in either test.ino or gyro.ino.  The calculations you show above are unlikely to work.

Code:
now = millis();
dt = (now-lastTime)/1000;  // This will produce dt=0 if 'now' and 'lastTime' are both unsigned long as they should be.
dt = now;  // Shouldn't this be "lastTime = now;"?
5  Using Arduino / Microcontrollers / Re: attiny85 timing clock incorrect on: Today at 07:59:36 pm
Did you do the Burn Bootloader step?  If not the ATtiny is probably still set for the factory default speed of 1 MHz (8 MHz internal clock and prescale of smiley-cool.  Your cycle time would then be eight seconds instead of one.
6  Using Arduino / Project Guidance / Re: NFC and Ethernet/SD shield stacked on Mega on: Today at 08:53:37 am
You can use any unused digital pin as an SS signal.  The easiest way will probably be to bend Pin 10 on the NFC shield and wire it to some unused pin.  Then you need to adjust the software to use the selected pin.
7  Using Arduino / Programming Questions / Re: Program For 2X Font Size Is Giving Me Problems! on: Today at 08:46:53 am
Perhaps you need to put lcd.begin() before the lcd.createChar() calls?
8  Using Arduino / LEDs and Multiplexing / Re: Question regarding PCF8574P usage on: Today at 08:36:49 am
The 4051 is an eight-way analog switch.  You can use it to expand the number of inputs but since you can connect the switch to only one pin at a time you can't use it to drive more than one output at a time.  It is typically used to expand the number of analog inputs but can also be used for digital inputs.

For digital output expansion many people use a 74HC595 shift register (serial in, parallel out) and the shiftOut() function or the SPI bus if you need high speed.

For digital input expansion many people use a 74HC165 shift register (parallel in, serial out) and the shiftIn() function or the SPI bus if you need high speed.
9  General Category / General Discussion / Re: Original or clone? on: Today at 08:28:14 am
Clone.  The original doesn't have the reset button in the upper left corner.  There should be a blank area there for a label.

But John, the pics on this very site show the R3 has the reset button top left....

http://arduino.cc/en/Main/ArduinoBoardUno

They moved it!  I guess I've never seen an R3 in real life.

Another difference: they seem to have taken the  "Made in Italy" text off the front (but not the R2-style back).
10  Using Arduino / Project Guidance / Re: Which LilyPad to use - noob on: Today at 08:09:14 am
Will I then be able to send right/left keyboard strokes that will affect whichever application that is active at that time?

No.  You will be able to read from the Bluetooth Mate as if it were a serial port.  You would have to write a program for the PC that would translate whatever serial messages are received from that serial port into keystrokes.

The Arduino Leonardo and other ATmega32u4-based Arduinos can emulate a keyboard if directly attached to the PC via USB.
11  Using Arduino / Storage / Re: Save serial.println to file on: July 29, 2014, 07:36:46 pm
You can copy and paste from Serial Monitor.

If you want neat columns you can use the tab ("\t") character.

If you want to import into a spreadsheet you can use commas to separate fields and save the text in a .csv (Comma Separated Values) file.  Then import that into your spreadsheet.
12  Using Arduino / LEDs and Multiplexing / Re: Question regarding PCF8574P usage on: July 29, 2014, 07:26:49 pm
Time to read the datasheet: http://www.nxp.com/documents/data_sheet/PCF8574.pdf

When set HIGH the outputs source a maximum of 300 MICROamps (0.3 mA).  That is so you can use them as inputs.  When set LOW they can sink about 20 mA.  That is why you connect the LED's between +5 and the output and you write it LOW to turn it on.
13  Products / Arduino GSM Shield / Re: ITEAD SIM900-GPRS-GSM-Modul doesn't work on: July 29, 2014, 02:47:47 pm
I don't think that GSM Shield is a clone of the official Arduino GSM Shield.  You should download the library and examples for the ITEAD shield and try those.
14  Using Arduino / Project Guidance / Re: airsoft prop feasability on: July 29, 2014, 02:29:19 pm
anyone got any tips on using a 9.6v 1200mAh battery to power this all?

You could hook that straight to the Arduino power jack but the linear regulator on the Arduino will be converting half your power into heat.  For longer battery life you should use a 5V DC-to-DC converter.  They are more efficient. 
15  Using Arduino / Project Guidance / Re: Shift registers and analog data on: July 29, 2014, 07:31:51 am
No, but you can use a 4051 analog multiplexer to select from among eight analog inputs.  You use three digital outputs to select which input goes to your voltage divider.
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