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Hall sensors or optical encoders are probably a good bet.

Eagle CAD.  You can grab it here: http://www.cadsoftusa.com/

Thank you very much for your help. It is very much appreciated.

I am planning a new project and andruino looks promising. I need to capture 24 bits every 15 ms and send it to the PC. I was looking at the Uno and the Mega models and I can decide which one to use.

Please advise,

Best regards,

Andres

Cadsoft Eagle -  http://www.cadsoftusa.com/

Either one should work fine.

Jeremy,

I have a fresh 13.37 x64 system and trying to compile some avr code. When I try to compile I get the following error ;

/usr/lib/gcc/avr/4.4.4/avr5/libc.a: could not read symbols: File format not recognized

Actually there were bunch of errors like ;


/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/../../../../avr/lib/avr5/libm.a when searching  for -lm
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/../../../../avr/lib/libm.a when searching for -lm
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: cannot find -lm
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/avr5/libgcc.a when searching for -lgcc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible /usr/lib/gcc/avr/4.4.4/libgcc.a when searching for -lgcc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: cannot find -lgcc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/../../../../avr/lib/avr5/libc.a when searching  for -lc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/../../../../avr/lib/libc.a when searching for -lc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: cannot find -lc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible  /usr/lib/gcc/avr/4.4.4/avr5/libgcc.a when searching for -lgcc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: skipping incompatible /usr/lib/gcc/avr/4.4.4/libgcc.a when searching for -lgcc
/usr/lib/gcc/avr/4.4.4/../../../../avr/bin/ld: cannot find -lgcc

and I copied the 64bit versions of the libraries to destination folders  and got rid of all the errors except that I am stuck at libc.a couldn't  read symbols.

So I am asking you, any help is appreciated.

which ardunio suitable for low power energy harbvesting from solar/wind/others  and can be connected to  Near Field Communication  (NFC) or RFID

Hi Jeremy. Im new to arduino technology and I want to embark myself upon a project.

I want to read the data from two accelerometers(x,y coordinates) and send this data wirelessly to an arduino board. I currently have two solutions:

1) One solution is to attach attach an Arduino to the object, and using an XBee shield to send data  from the accelerometer to another Arduino (or desktop machine)

2) Another solution proposed by a fellow engineer was to connect the accelerometers to an XBee antenna,

then having your Arduino paired with an XBee shield to receive data. Is that possible?

I personally like solution number 2 the most because space is an issue in this project.

Do you think there is a better approach to this problem? What advise would you give me?

2) What arduino board do you suggest I should buy first in order to start developing this project. I have seen many arduino

boards, but im unsure which one to buy.

Jeremy, thanks for being such a great resource...I am a complete newbie but wanting to learn fast. My project is to take the voltage measurements (0 to 2 VDC) from two distinct sensors and use a look-up table that I have for these sensors to convert them to temperature readings, and then display the temps on an LCD (at a later date would like to access them through the internet if that is possible). How do I do all this? How do I enter the look-up table? How do I display the temperatures? Can I store these temp and download at a later time?

If this is too simple, pls direct me to another site as not to be a nuisance.

Thanks for your help.

Regards,
David

What is the temp sensor you are using?  Most of them are linear and you can calculate the temperature very simply from the voltage read rather than use a lookup table. For storage and later retrieval, Arduino has a 512 byte EEPROM you should be able to store a hundred readings in that.  See the EEPROM library on the Arduino site.

Here is some code you can study from a class I took. It reads from a TMP36 sensor and sends the reading to both serial and a parallel LCD.

/* Sensor test sketch
  for more information see http://www.ladyada.net/make/logshield/lighttemp.html
  */

#define aref_voltage 3.3         // we tie 3.3V to ARef and measure it with a multimeter!

// include the LCD library code:
#include <LiquidCrystal.h>
// initialize the LCD library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

//TMP36 Pin Variables
int tempPin = A1;        //the analog pin the TMP36's Vout (sense) pin is connected to
                        //the resolution is 10 mV / degree centigrade with a
                        //500 mV offset to allow for negative temperatures
int tempReading;        // the analog reading from the sensor

void setup(void) {
  // We'll send debugging information via the Serial monitor
  Serial.begin(9600);
   lcd.begin(16, 2);  // for debug
  // If you want to set the aref to something other than 5v
  analogReference(EXTERNAL);
}

void loop(void) {

  tempReading = analogRead(tempPin);

  Serial.print("Temp reading = ");
  Serial.print(tempReading);     // the raw analog reading

  // converting that reading to voltage, which is based off the reference voltage
  float voltage = tempReading * aref_voltage;
  voltage /= 1024.0;

  // print out the voltage
  Serial.print(" - ");
  Serial.print(voltage); Serial.println(" volts");

  // now print out the temperature
  float temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset
                                               //to degrees ((volatge - 500mV) times 100)
  Serial.print(temperatureC); Serial.println(" degress C");
  lcd.clear();
lcd.print(temperatureC);

  // now convert to Fahrenheight
  float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
  Serial.print(temperatureF); Serial.println(" degress F");
  lcd.setCursor(0,1);
lcd.print(temperatureF);
  delay(1000);
}