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106  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: one general question concerning RFID readers.. on: April 17, 2006, 06:26:48 pm
hey nima,
I'm very courios to know your set up.
what reader are you using? how do you connect it to arduino?

107  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Arduino call and response on: April 20, 2006, 11:13:49 am
I think that the serial buffur is by directional...
it goes through 2 different pins
Rx  stands for Receive and
Tx stands for Transmit
so it won't read what it is transmitting...
it's pointless: whoever sends an info knows what it is sending!!! smiley

to SEND somenthing to the pc (connected either via usb or serial cable)
use any one of the "print" commands available
read the reference

and to READ somenthing coming from the pc
use serialRead()

beware of initializing the serial communication in the setup loop by writing

108  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: wiki please on: March 16, 2006, 06:03:59 am
I totally Agree,
we need a wiki for code, for circuitry, for tutorials, and for single component collection...

sparkfun has an opencircuit wiki
that we could eventually use, but I feel more confortable if we could give it a more "designer oriented" type of information...and host it at "out place" :-)

I'm fairly new to electronics and what I would find very usefull is a collection of already explained components (cut down to a designer's mind) with explained what it is used for, how to use it with a sample code and circuit, where can it be found etc..
today this kind of information needs to be tracked down in numerous forum posts...very usefull for a work in progress but quite difficult to find a second time.

instead of asking all the time what multiplexer is better for this and that..what motor driver...what led driver ecc...we could search the common database contributed by users...

I know that you are all buisy and that you already thought of all this.
I also know the spamming problems..
but I agree that there should be a common place for users...

I'm switching host right soon as I'm perfectly confy with it I'd like to set up such a wiki for the Arduino comunity with the possibility to switch it to the Arduino domain as soon as it is possible.

109  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: How to communicate between 2 boards? on: March 13, 2006, 04:36:00 pm
you can create your own "protocol" to ensure that they are syncronized

- the sender sends a char "s" and loops untill it receives a confirmation "c" from the reader before starting its synchronized tasks
- the receiver repetedely reads the serial untill it receives the "s" (for start value)
- when it receives the "s" from the sender it will send back a "c" and start its main loop
- the sender will receive the "c" that will make it start its main loop...

this is my crunchy version smiley
there probably is a better way or some special code in the Rs-232 serial protocol for bit sincronization...
but I certainly don't know it smiley
if you discover please tell us.

but I imagine doing this blinded without a serial out on the pc screen is kind of hard...
good luck

ps. have a look at in the actionscript class example I've set up...
I had to create exactly that wait and response inside both Arduino and Flash...might give you some hints smiley
110  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: How to communicate between 2 boards? on: March 13, 2006, 02:14:56 pm
hey kr1,
it seems that you are continuously sending and empty byte...that might be the problem!
try setting a value to txVal
either in the declaration
byte txVal = 10;
(more appropriate is to make it an Integer ->  int txtVal = 10; and use printInteger(txVal) )

or in the loop      

void loop () {
       txVal++; //add 1 to txVal at every loop
       printByte(txVal); //send the new value of txVal

or you can do both ( but start txVal = 0) else you wont see the effects

in the receiver board you could also make the led blink as many times as the txVal

if(serialAvailable()) {
    rxVal = serialRead();
    for(i=0; i<rxVal; i++) {
         digitalWrite(ledPin, HIGH);
         digitalWrite(ledPin, LOW);

you will need to synchronize the sender's and receiver's delays
because the receiver wont read again the serialbuffer untill it has completed blinking the first value it reads (if rxVal = 10 and every "for" loop takes 500+500ms = 1 second to complete, the receiver will redo the reading of the serial buffer only after 10 secs...but in the meantime the sender board has gone way faster ahead with its small delay(10); of 10 milliseconds

I've never tested this in making 2 boards's just an idea smiley

hope it helps
111  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: cant even turn LED on on: March 10, 2006, 01:25:43 pm
test it with your brand new voltmeter and see it for yourself ;-)

(remember to connect it to ground)

VCC stands for Voltage Common Collector

112  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: cant even turn LED on on: March 09, 2006, 05:41:24 pm
there is a very simple and immediately satisfying way to check if your board is working properly and that is:

put a led between pin 13 and its closest pin called GND
which stands for ground.
just put the led's longer leg (+) inside pin 13 and the led's shorter leg (-) inside GDN.
You don't even need a resistor because the board already integrates one that goes into pin 13. (achtung: this is the only pin that has this feauture)

once you've put the led like that you can press the reset button on the board to chek if it's should blink 2-3 times to tell you that the bootloader is correctly installed in the microcontroller and that it is waiting for you to send him a program from the computer.

- open the simplest example...the "led blink" inside your arduino software IDE (check in tools > serial port if it's addressing the right COMport where your arduino is connected)
- if you read the program you should see that it is addressing pin13 for the led
- press the "verify" button to compile the program
- press the reset button on the board
- and right after press the upload button on the IDE
- wait untill it has been properly uploaded and enjoy smiley

113  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: cant even turn LED on on: March 09, 2006, 03:28:15 pm
from what it seems you are not connecting your breadboard to ground!
you need to connect the blu stripe, right under the blu minus sign to arduino common ground!
if you look on the arduino board in the "POWER" section there is one pin that outputs 5V, 2 pins called "GND" which stands for GROUND, and a pin that outputs 9V.
You need to connect one of the two Gnd pins with the rightmost blue line in your breadboard (According to your diagram) that the 470 Ohm resistor connects to ground and closes the circuit

as for the ledPin = 5
it is probably speaking of the DIGITAL pin 5
the other "5" that you might be referring to
belong 1 to the POWER section and it just says that it has 5Volts coming to that pin

and the other belongs to the ANALOG IN section
which as the name says are mainly used to send Analog data to the microcontroller.

do you have clear the difference between digital and analog ? smiley sorry for the question smiley

hope it helps
look under the tutorials for reference image

114  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: wireless wearable display project on: March 08, 2006, 09:08:54 pm
I wanted to do the same thing...
I'm waiting for the bluetooth arduino to do the wirelles s part ;-) (that is going to be very soon I hope )

in the meantime you can read leah buechley's excellent references and diy projects...
she's already done (on Pic) all this kind of things... ;-)

now you just need to push the boundaries ;-)

115  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: reading a microphone and tone recognition on: February 24, 2006, 10:55:07 pm
hey we are discussing the same thing on another thread...;action=display;num=1138827944

read it and report on your results please smiley

116  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: string library ? on: February 21, 2006, 01:25:29 pm
salut, smiley-wink
I'm a newbie as well in Arduino...and in C...
I've started studying C thanks to arduino and going deeper now.
I've no clue yet on how to use the string library (I thought it was stdio.h but couldn't find it nor make it work)
here are a few resources for C:

- the excellent howstuffismade C article
(very good at explaning pointers)

- teach yourself C in 24 Hours online book

- teach yourself C in 21 days online book

- some more low level C for microprocessors

- as a compiler I chose MinGW
which is very geeky and low level (you must compile through command line) but if you will choose it I can give you a sample .bat file to automatize the compilation. Maybe you can test DJGPP and tell me how it is ;-) would have been my next test, but I haven't had time yet to look over it.

I'm not sure if I made the right choice, maybe Massimo or someone else has a better platform to suggest... I even thought if it was possible to compile in C through arduino since it uses gpp as all the other free compilers...but I'm not sure of that yet...this is one of the questions I will put on the "other" thread smiley

besides that...
where are you from? I lived for almost two years in Paris and I can understand that you like accents smiley

hope this helps
à bientot (sorry! no accent aigu dans mon clavier ;-) )

ps. did you read the datasheet for your LCD? you might find valuable info in it.
117  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: string library ? on: February 20, 2006, 09:56:38 pm
yeah great!
thanks! smiley
can't really understand why you are feeling nice!? ;-)

in fact I've seen that in the lib/avrlib folder there is actually an lcd.c and lcd.h and much more...there is even a servo.c library (I couldn't find the stdio.h though) but this is not used in the
tutorial and I can't really understand why we can't use these with Arduino (at least this is what I've been led to think because no one in the forum talks about this hidden goldmine ;-) )

I'm not interested in the lcd functions right now smiley
thanks anyhow.  smiley
what I'm really interested is in understanding the guts of Arduino software...and in particular to better understand what are the steps to implement it for another microcontroller (AVR and PIC), and many many more things...but I want to write them all at once on a new thread smiley

I don't want to take the thread away from mrbpp

hear you soon

118  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: string library ? on: February 20, 2006, 08:06:41 pm
that's a good question...
I've also wondered what can be brought to Arduino from C
how to integrate libraries we find around or have available...
and that gets us to a way bigger question which is...what is the exact structure of Arduino (software)
but I will post a full thread on that.

for example this guy here has some routines for the atmega16 (not that far from the atmega8 smiley-wink )
to easily connect an LCD... I know that the processor is different but how can we integrate that code (or a subset) into Arduino? how do you extend arduino...besides adding code directly in you project file.

anyhow, I had problems with strings as well,
I needed to be able to pass full strings back and forth from flash
you can check for some code I've wrote that you might find usefull.
It passes "strings" all in one time (actually sending them char by char but it's completely invisible to you)

hope it helps

119  Forum 2005-2010 (read only) / Bar Sport / Re: Arduino Robotics Project on: January 06, 2007, 07:43:11 pm
hehehe find something really stupid that you want your robot to do and go for it smiley

you probably might be interested in seeing the asuro robot...
it's a kit that is built upon the atmega 8 and that has wireless IR comunication with the pc.

you could probably stick asuro parts in your shell to have a super asuro...
120  Forum 2005-2010 (read only) / Bar Sport / Re: Required reading in electronics on: January 02, 2007, 07:12:46 am
if you wanna go really cheap
go to
it's a good compromise between theory and practice
be sure to hop back and forth from the volume you want to read and the correspondent chapter
in the volume VII - experiments
it helped me a lot.

although I would suggest as well tom igoe's book. very comprehensive and cut down to designers minds, even if it doesn't have arduino examples it's very easy to port to them

hope it helps
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