No, without using any kind of isolation.

Oh, by the way in tools -> serial port it appears as: /dev/tty.usbserial-A400eNFz

And in tools -> board it'll work with both Arduino Duemilanove w/ATmega328 and Arduino Pro or Pro Mini (5V, 16MHz) w/ ATmega328

[In case you cant upload the sketch file,-1. Press the upload button on your IDE-2. Hold the reset button on your Arduino Pro Mini.-3. Release the button upon you see the first blink on the FTDI board!At this time moment in time the sketch should be acknowledged by the board!Hope that this helps you all!Peace.]

Right so, I installed the drivers and still didn't work so:
on youtube I found this:
In case you cant upload the sketch file,
-1. Press the upload button on your IDE
-2. Hold the reset button on your Arduino Pro Mini.
-3. Release the button upon you see the first blink on the FTDI board!
At this time moment in time the sketch should be acknowledged by the board!
Hope that this helps you all!
Peace.

I have to do this every time, but it works.

Is there a problem with auto reset?? I had the RST pin on the Pro Mini (tested to GND and it works) attached to pin 3 of the USB Serial adapter.

I'm using a Arduino Pro Mini 5v/ atMega 328 and a iMac OSX. Trying to program with the latest version of the Arduino serial USB connector.
I joined all the cables properly (tried switching RX-RX & TX-TX // RX-TX & TX-RX around).

I only get the apparently typical steady red light and blinking green light on the pro mini.
To begin with there is no "USB........" in the arduino tools -> serial port, which there is with my mega.

Ant ideas of what's the problem??
ty in advance

Would I damage the Arduino by feeding input and outputs to and from it without any isolation? (transistor, optocoupler)

Maybe other kinds of wireless communication would be faster and/or more suitable for you:

http://www.creativeapplications.net/sound/wireless-arduino-of-tutorial/

RPF

Well, I'm guessing you'd have to make the arduino type in the password (as a USB keyboard (and USB mouse to click on user account)) when it reads the appropriate tag and as soon as you log out have a processing sketch notify the arduino about it and put it out of standby mode ready to read a tag again.

Hope you got inspired, 

Yep, make sure you understand how everything works separately and then slowly join it all. This way you save lot's of time (even though it might not look like it) and makes debugging a lot simpler.

Have fun!!

I'm applying a similar concept and also thought of starting as you are.
Problem is when people entered clumped up or brought objects in with them (shopping cart...)
Way I got around it is a US sensor crossing the doorway and a PIR sensor inside. So every time US detects sudden change it'll check if there is still movement inside or not and thus knowing if there are none, one or two+ people in the room.

another problem is closing the door, normally that would count as someone coming in/out.
Since the door is an electric sliding one, I solved that by adding increment values into the code. If the increment/decrement of distance the US reads matches the sliding door speed (door is pretty thick, about 10 cm) then that's the door opening/closing(depends on wether increment or decrement) if there is a sudden increment followed by a sudden decrement, someone came in/out.

Here's how it knows how many people are in:
-----no people  = no PIR movement
-----1 person   = US detected sudden inc/decr + PIR detects movement
-----2+ people = 1 or 1+ people are in and the US detects entrance/exit while PIR detects movement


Hope I helped, or at least got ya thinking 

What does this mean:
quad buffer/line driver with 3-state outputs controlled by
the output enable inputs
I tried goggling around but I don't see how it should help?

I WANT:
An arduino Pro Mini 5v to:
-Know when a button on the calculator is pressed.
-Press buttons on the calculator(buy connecting two connection points)

HOW?:
Know when a button is pressed by reading a change in voltage between connection points.
Use transistors to connect two connection points, transistor's base (B) to arduino.

MY PROBLEMS:
Will feeding a cable from the connection points on the calculator to the arduino damage the arduino? or even work?
Can I join two connection points on the calculator using the arduino, not transistors? ( the two connection points have to be wired one to another, NOT to GND or Vcc)

[Do I have to join GND like when wiring a Servo????]

Would I damage the arduino by feeding the contact points on the calculator to it as inputs?
Do I have to join GND like when wiring a Servo????  (1.5v cicuit of the calculator and 6v circuit of the arduino)

[(is there a way the arduino can do this without transistors)]

Hello!

I'm trying to hack a CASIO fx-85ES calculator:


I want to use the calculator as a keypad (arduino knows what button you pressed) and display (arduino "presses" a button), using an Arduino Pro Mini (5v).

buttons are pressed by connecting two contact points on the board:

 for example: K07 + KI5 = "1" or K01 + KI2 = "4"
I only want to use the following keys: 0-9, +, -, x, :, =, and ")". total of 16 buttons

I plan to:
Connect points using transistors "press buttons". (is there a way the arduino can do this without transistors)
Use pins as input to read buttons pressed. (or more transistors?)

Note: I will only use calculator as INPUT OR OUTPUT never both at once.

Anything I forgot or suggestions? what do you think, could this work?

TimeSerial.ino, still nothing.

Arduino output:

Code:

TimeSerial:24: error: 'time_t' does not name a type
TimeSerial.pde: In function 'void setup()':
TimeSerial:20: error: 'requestSync' was not declared in this scope
TimeSerial:20: error: 'setSyncProvider' was not declared in this scope
TimeSerial.pde: In function 'void loop()':
TimeSerial:29: error: 'timeStatus' was not declared in this scope
TimeSerial:29: error: 'timeNotSet' was not declared in this scope
TimeSerial:31: error: 'timeSet' was not declared in this scope
TimeSerial.pde: In function 'void digitalClockDisplay()':
TimeSerial:39: error: 'hour' was not declared in this scope
TimeSerial:40: error: 'minute' was not declared in this scope
TimeSerial:41: error: 'second' was not declared in this scope
TimeSerial:43: error: 'day' was not declared in this scope
TimeSerial:45: error: 'month' was not declared in this scope
TimeSerial:47: error: 'year' was not declared in this scope
TimeSerial.pde: In function 'void processSyncMessage()':
TimeSerial:65: error: 'time_t' was not declared in this scope
TimeSerial:65: error: expected `;' before 'pctime'
TimeSerial:69: error: 'pctime' was not declared in this scope
TimeSerial:72: error: 'pctime' was not declared in this scope
TimeSerial:72: error: 'setTime' was not declared in this scope
TimeSerial.pde: At global scope:
TimeSerial:77: error: 'time_t' does not name a type

Processing output:

ArrayIndexOutOfBoundsExeption:1
Quote
Exception in thread "Animation Thread" java.lang.ArrayIndexOutOfBoundsException: 1
   at SyncArduinoClock.setup(SyncArduinoClock.java:47)
   at processing.core.PApplet.handleDraw(Unknown Source)
   at processing.core.PApplet.run(Unknown Source)
   at java.lang.Thread.run(Thread.java:662)

[/quote]

Is the Time.h file not in the right place?