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1  Using Arduino / Project Guidance / Re: Need help to splitt a string that comes from serieport on: August 20, 2014, 11:53:53 am
Where does the string come from?  If your reading it character-by-character from a stream, I would say your best bet s to parse it on the fly.  If you have to parse the string in memory, have a look at strtok()

You can google for zillions of examples.  Your code would give <BS><CR><LF> ("\b\r\n") as delimiters, then look at the strings found.  The ones that aren't "" are what you are looking for.
2  Using Arduino / Programming Questions / Re: I cant insert code, please help..... on: August 18, 2014, 10:35:22 am
this is going to be very vague

Agreed: vague in the extreme.

It is not possible for anyone to help you without at least one of, and ideally both of:

(1) the whole actual sketch you are struggling with, and
(2) the whole actual error messages given by the IDE when you build it.

is there a tutorial about when, where, why and how to use the "{ }" syntax
3  Using Arduino / Project Guidance / Re: ultrasonic ground speed detection on: August 18, 2014, 09:58:52 am
Think ball-less mouse.

I was reading this:

I wonder if you could replace the lens system in a mouse's optical imager to focus on the ground 15cm below and just use the mouse's movement outputs to read the speed, direction, distance traveled and so forth.

I have a vague idea to try placing a parallax ping style sensor at a 45-degree angle to the direction of travel and see if there is a detectible shift in the distance it reads with relative movement.  That would be a simple experiment to try, even if it is unlikely to be successful.
4  Using Arduino / Project Guidance / Re: Animatronic Iron Man Suit Feasibility on: August 18, 2014, 09:34:37 am
Most RFID systems would not read very well through a (distance equivalent to a) persons head, so I think you'd need separate readers on each side.  In this case it would be fine to use the same tag on both sides, as the logic depends on which side reads the tag.  Two readers within 20cm of each other might cause some interference.  It might be desirable to power them alternately rather than both simultaneously.

If you wound your own coil for an ID02, you might get reasonable readings on both sides.  A coil could be mounted inside the mask, canted so that it passes on one side of the eyes and on the other side of the neck.

All of this would require trying it to see what works.

5  Using Arduino / Project Guidance / Re: 6' Groundwater Level Meter on: August 15, 2014, 10:39:15 pm
I originally got started after reading this:
They reported that a 50mm (2-inch) pipe resulted in limited range.  I only needed 1,000 mm range or so, but I went with a 100mm pipe, mostly because that was available.  My sensor is a seeed studio one that operates the same as the parallax ping.

The parts you'd need to have to just experiment a bit are pretty cheap.  I would recommend buying a couple of the cheaper ones and just see how it all works.

In my application I run the sensor, an Arduino pro, a 433MHz radio and some other electronics from a 7Ah gel cell.  It draws about 25mA on average, reading the water level every 15 secs or so.
6  Using Arduino / Project Guidance / Re: Arduino Wireless Configuration Parameter to Control via RS232 on: August 15, 2014, 09:00:21 am
is it generell possibile to get this szenario done? 

Yes, of course it is possible.  Go for it.
7  Using Arduino / Programming Questions / Re: Pass const char [4][20] PROGMEM into function on: August 14, 2014, 10:06:31 pm
Something like this would work

void init_menu(const char menu[][20])
  char sbuff[20];
  for( uint8_t i=0; i<4; i++ )
    lcd_set_cursor( 0, i );
    strcpy_P( sbuff, &menu[i][0] );
    lcd_print_string( sbuff );


It would be an idea to use a zero-length string to end your menu, then the loop can loop until strlen(sbuff) == 0.  That way your menus don't have to have exactly 4 entries.
8  Using Arduino / Project Guidance / Re: 6' Groundwater Level Meter on: August 14, 2014, 08:55:44 pm
I have been reasonably successful measuring water level in a 100mm ABS tube using a parallax ping style sensor like this one:

I would say that that accuracy is closer to +/- 15mm than the 2mm some models claim.  There are dozens of versions of these things.  I've seen them as cheap as $3 on ebay.

For a permanent installation in a humid/damp location, you might want to try a weatherproof sensor.  Those will cost a bit more.  There are tons to choose from.  Here's a supplier for a range of options:
9  Using Arduino / Programming Questions / Re: Am I doing something wrong with PROGMEM? on: August 14, 2014, 08:34:36 pm
There is a known bug that PROGMEM generates spurious warnings when compiling C++.

I believe it is fixed in a version of AVR-GCC that has not been picked up by Arduino.  My reading leads me to believe that it is harmless.
10  Using Arduino / Programming Questions / Re: Identify SIM Phone Number via Serial.print on: August 14, 2014, 08:26:53 pm
Look up the +CNUM command:
AT+CNUM´╝Üread subscriber MSISDN
11  Using Arduino / Programming Questions / Re: Help needed - SIM900 send/receive SMS with SMS response and LED control on: August 11, 2014, 12:08:24 pm
When I google "arduino simcom sim900" I get several hits.

Maybe one of these would help you.
12  Using Arduino / Project Guidance / Re: Receiver signal strength 2.4ghz wireless on: August 01, 2014, 02:27:12 pm
That is an nRF24 part.  Are you using the RadioHead library with it?
I doesn't look that these guys give you a usable RSSI.

The hardware has:
In RX mode a Received Power Detector (RPD) signal is available. The RPD is a signal that is set high
when a RF signal higher than -64 dBm is detected inside the receiving frequency channel.

If you felt like hacking RadioHead to read out Received Power Detector (RPD), located in register 09, bit 0 you would at least know if the received signal is < or > -64dBm.
13  Using Arduino / Programming Questions / Re: Pointer problems on: August 01, 2014, 11:00:38 am
parms * TparmsA = new parms[num_of_parms];

What is the value of num_of_parms? And do you check that TparmsA is not NULL?

This is an AVR Ardunio, yes?  Assuming so, there is so very little memory around than any sort of dynamic memory allocation is a total crap shoot.   holmes4's suggestion to read the parameters one at a time into a statically allocated instance is the right way to go, IMO.
14  Using Arduino / Interfacing w/ Software on the Computer / Re: How to get output of system() command? on: July 29, 2014, 11:28:03 pm
Where does the Arduino come into play? There is no system() on Arduino.
15  Using Arduino / Project Guidance / Re: Gprs connection on: July 29, 2014, 11:13:31 pm
Maybe there is a free tier amazon service that would suit your needs
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