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1  Using Arduino / Project Guidance / Re: sim card for GPRS shield in USA on: April 21, 2014, 12:26:15 pm
Verizon phones operate on CDMA, which is different hardware than the GSM/GPRS module I want to use.  So a Verizon SIM card is useless.  Any other ideas?
2  Using Arduino / Project Guidance / Re: Are there any small Arduino boards with Ethernet built-in? on: April 15, 2014, 02:45:55 pm
I don't know if you're interested in wifi, or only Ethernet, but these boards look interesting:  https://www.spark.io/

Tiny boards with built-in wifi.  And cheap!  Seems like an awesome idea, but I don't know much about them.  Maybe someone else has some experience with them?
3  Using Arduino / Project Guidance / Re: sim card for GPRS shield in USA on: April 15, 2014, 02:43:00 pm
Does anybody have a SIM provider suggestion?
4  Using Arduino / Project Guidance / sim card for GPRS shield in USA on: March 08, 2014, 09:51:39 pm
I've got a GPRS/GSM shield that I'd like to use, but I don't know where to get a SIM card for it.   I'd like to get a pre-paid one instead of signing some kind of agreement with a carrier, but is that possible?  It seems like lots of people are successfully using GPRS/GSM shields but I can't find any mention of what type of sim card or carrier people are using here in the US. 
5  Using Arduino / Interfacing w/ Software on the Computer / ethernet logger posting to remote file with php on: January 28, 2014, 02:16:26 pm
I have a logger that I built using the new Uno+Ethernet board. It records data from a bunch sensors, and puts all of the values into a string. I'd like to transmit that string every 10 minutes via the internet to a remote server that's running a php script that will append the incoming string to a text file on the server. The problem is that I can't find any examples of a php script that will do this. I know absolutely nothing about php scripts, so I'm looking for a basic examples that takes the incoming string from the arduino's GET or POST request and just appends it to a text file. I've found enough examples of Arduino sketches to figure out how to transmit the string, I just need help on the php side. Thanks!
6  Using Arduino / Programming Questions / Re: converting captured string to floats on: November 06, 2013, 11:21:58 am
I finally found a solution that is pretty simple and seems to be capturing the data correctly, using the parseInt() and parseFloat() functions.

Code:
  if (mySerial.available() > 0) {
    int x = mySerial.parseInt();
    float y = mySerial.parseFloat();
    int z = mySerial.parseInt();
    }
 
7  Using Arduino / Programming Questions / Re: converting captured string to floats on: November 04, 2013, 11:33:16 am
I thought there were going to be some new-fangled parsing functions included in the new Arduino 1.0 IDE, but I can't seem to find how they might be used in this case.
8  Using Arduino / Programming Questions / converting captured string to floats on: November 04, 2013, 10:25:33 am
I have an arduino device that captures incoming serial data from a sensor in the string that is made up of three numbers, separated by spaces, and ending with a letter, usually looks like this:    -24 55.5 243t

I used to have an older sensor that outputted 3 integers, which was easy to parse using the following code.  But now that the middle number is a float, my code breaks.  I know that not many people recommend using the scanf() function anyway, and it appears it doesn't work for floats.  I can't figure out how to use atof() on an array like this one.  Is there a better option that I should try?

Code:
int x,z;
float y;
String testString = "-15 22.8 402t";

void setup()
{
  Serial.begin(9600);
}

void loop() {
  
  Serial.print("testString = ");
  Serial.println(testString);  //so you can see the captured string
   char Carray[testString.length() + 1]; //determine size of the array
   testString.toCharArray(Carray, sizeof(Carray));
  Serial.print("Carray = ");
  Serial.println(Carray);
   sscanf (Carray, "%d %f %d", &x, &y, &z);
  Serial.println("THE DATA:");
  Serial.print("first= ");
  Serial.println(x);
  Serial.print("middle= ");
  Serial.println(y);
  Serial.print("last= ");
  Serial.println(z);
  
  delay(5000);  

  }
9  Using Arduino / General Electronics / calculating battery life with intermittant load on: February 06, 2012, 11:34:55 pm
I've got a circuit that draws 15ma when powered on, and draws no current when off.  If it's only active for 5 seconds every 5 minutes, how long will it last if I have a battery pack with a 2000mAh capacity? 
10  Using Arduino / Programming Questions / XML parsing on: October 28, 2011, 02:30:38 pm
I have a device that is outputting XML data via a serial line every few seconds.  I need to interface an Arduino with it to parse the data and then do some other stuff with the values it gets.  This is a standalone portable unit that only exports XML and I don't want to connect a PC or something else to handle the data.  I'd like the Arduino to do the parsing if it's possible.  The datastream looks like this:

<data><celltemp>5.13581e1</celltemp><cellpres>1.01388e2</cellpres></data>

What is the preferred method for parsing the two number string out of the above text and once I do that, is there a good method for converting 1.01388e2 to 101.388.

11  Using Arduino / Networking, Protocols, and Devices / Re: sending text strings through xbee mesh on: October 08, 2011, 04:39:22 pm
Each of my arduino logger nodes have unique names anyway, so it's not a problem to tack that on to the beginning of the string.  I just wasn't sure if API mode was more efficient in terms of the actual packets that are being transmitted, or am I losing some cool features of API mode if I choose transparent mode.
12  Using Arduino / Networking, Protocols, and Devices / sending text strings through xbee mesh on: October 07, 2011, 11:20:06 pm
I've been working my way through Rob Faludi's WSN book, and I have successfully sent text strings from one arduino to another using my series 2 ZB xbee units in transparent mode.  I also did his example of having 3 router/endpoint nodes transmitting temperature data to a coordinator with API and displaying the live data on the Processing thermometer graph.  But those nodes sensed the temperature from a sensor on their own analog input pins.   I have arduino-based loggers with multiple sensors on them that require a more complicated interface than I can achieve with the onboard I/O of the xbee.  Currently the loggers just write the data to an SD card, but I'd also like to transmit it via the xbee.  How do I go about sending a string of text through the mesh and have it arrive in one piece at the coordinator?  Is it simply a matter of saying "Serial.print("23 degrees, 0.58 cm, 4.5 volts") on the serial input of the end node, or do I have to use a special protocol?
13  Using Arduino / Programming Questions / best method for implementing a timer on: September 12, 2011, 10:30:07 pm
I'm building a device with an Uno that'll have an LCD display showing the length of time (mm:ss) that has elapsed, and then every 5 minutes it'll need to be reset to 00:00 and started again.  The catch is that during the period it's showing the time, I also need to be reading a few sensor inputs and outputting some serial data, so I can't simply use a delay for the timer.

Should I just use Timer0 and millis to do some arithmetic, like:  if(currentMillis - previousMillis > interval)....   so it'll only update the display when a certain interval (1000 millis) has passed, meanwhile the main loop will keep looping and doing other stuff.

or is there a timing library that would be easier to help keep track of seconds and minutes?  I'll also have a DS1307 RTC onboard, so should I just poll that every loop to get the current time and then do the math like above?
14  Using Arduino / General Electronics / Re: how to get a stable 5v reference on: July 20, 2011, 06:03:20 pm
That looks great, thanks!  There are so many ADC chips out there that I've had a hard time trying to figure out which one to use, but that one seems like a good one to start with.
15  Using Arduino / General Electronics / Re: how to get a stable 5v reference on: July 20, 2011, 12:27:59 pm
So use  the 5V 1A switching regulator, will be a very stable 5V source for your 25mA plus the arduino's 30mA.
Use the analog devices SPI ADC that's been posted previously with 6 sample & hold inputs & get 6 conversions at the same time.

Do you happen to know the part number of that ADC?  I've been searching for days and haven't found one with 0-5v input and multiple channels.
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