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1  Using Arduino / Motors, Mechanics, and Power / Re: Reasons for motor shield? (general question) on: January 29, 2014, 12:27:52 pm
Thank you both!
2  Using Arduino / Motors, Mechanics, and Power / Reasons for motor shield? (general question) on: January 29, 2014, 11:45:17 am
Hi,
I'm curious why someone would use the Arduino motorshield, rather than building either a transistor H-Bridge, with a seperate power supply for a dc motor, or using relays to separate the power supply for a servo motor.  Is it just easier, or part of the Arduino system? I've noticed the heat sink on some of them. I've never used this to power motors. Generally speaking, am I missing out, by not using the motor shield?

Thanks

Oh!, and additionally, how much current is required to pulse a servo with PWM. Assuming a series of motors are all expected to move in exactly the same way, couldn't I use one arduino pin to send pwm to all the motors at once?
3  Topics / Device Hacking / Help with avr-objdump and disassembly on: December 19, 2013, 09:31:39 am
I've got an Arduino Mega board running a light display with 6 7-segment displays, and a bunch of bulbs. Sorry for the vagueness, I didn't design it, but I'm trying to figure out the design because it's been vandalized, and I've been asked to fix it. I could simply start putting wires in random header plugs, but that seems stupid. I'd rather look at the code stored on the Mega, and see if I can make heads or tails of the pinouts. I know the IDE has converted the code to a low level programming language, but is there a way to pull the hex/assembly off the arduino and disassemble it, using something like this http://onlinedisassembler.com/odaweb/#view/tab-assembly or Hopper http://www.hopperapp.com?
I'm using a Mac, and I've read to open up a terminal window and run avr-objdump and avr-readelf to get the assembly code.
 
I'd like to make sure I don't accidentally erase what is already running on the Mega.
4  Using Arduino / Sensors / Re: Trouble with graphing analog input to Processing on: December 06, 2012, 11:50:11 am
ok, I know this is gonna sound really silly, but my computer clock was set to a date in 1969. I set it correctly and the error message stopped popping up (on one file). But the program in processing keeps crashing. So I tried the simple analog read program, the example is listed in processing, and got the rxtx mismatch error again, and then it crashed my processing sketch. I'm running the stable version of Processing 1.5.1 on Mac OS 10.4.

I'm also running into the problem where the serial monitor isn't mapping the changes in my analog sensor. Same results no matter what. The arduino board, however, does notice the changes, so I know the error isn't with my schematic. I'm just projecting that this will be the next error I have to solve getting this project up and running, but they might be connected errors.
5  Using Arduino / Sensors / Re: Trouble with graphing analog input to Processing on: December 05, 2012, 09:40:53 am
I fixed that, but that wasn't it. It might have something to do with installing the current version of processing, then installing an older version. I'll try reinstalling it.
6  Using Arduino / Sensors / Trouble with graphing analog input to Processing on: December 04, 2012, 11:25:09 am
Trying to use the basic Graph setup from the examples library.
I'm getting the following error in Processing:

Quote
WARNING:  RXTX Version mismatch
   Jar version = RXTX-2.2pre1
   native lib Version = RXTX-2.2pre2
  • "/dev/tty.modem"
  • [1] "/dev/cu.modem"
    [2] "/dev/tty.usbserial-A700eXmJ"
    [3] "/dev/cu.usbserial-A700eXmJ"
    dyld: lazy symbol binding failed: Symbol not found: _open$UNIX2003
      Referenced from: /Applications/Processing 2.app/Contents/Resources/Java/modes/java/libraries/serial/library/macosx/librxtxSerial.jnilib
      Expected in: /usr/lib/libSystem.B.dylib

    dyld: Symbol not found: _open$UNIX2003
      Referenced from: /Applications/Processing 2.app/Contents/Resources/Java/modes/java/libraries/serial/library/macosx/librxtxSerial.jnilib
      Expected in: /usr/lib/libSystem.B.dylib
[/color]

Here's my code in Processing:

Code:
// Processing code for this example
 
 // Graphing sketch
 
 
 // This program takes ASCII-encoded strings
 // from the serial port at 9600 baud and graphs them. It expects values in the
 // range 0 to 1023, followed by a newline, or newline and carriage return
 
 // Created 20 Apr 2005
 // Updated 18 Jan 2008
 // by Tom Igoe
 // This example code is in the public domain.
 
 import processing.serial.*;
 
 Serial myPort;        // The serial port
 int xPos = 1;         // horizontal position of the graph
 
 void setup () {
 // set the window size:
 size(400, 300);        
 
 // List all the available serial ports
 println(Serial.list());
 // I know that the first port in the serial list on my mac
 // is always my  Arduino, so I open Serial.list()[0].
 // Open whatever port is the one you're using.
 myPort = new Serial(this, Serial.list()[0], 9600);
 // don't generate a serialEvent() unless you get a newline character:
 myPort.bufferUntil('\n');
 // set inital background:
 background(0);
 }
 void draw () {
 // everything happens in the serialEvent()
 }
 
 void serialEvent (Serial myPort) {
 // get the ASCII string:
 String inString = myPort.readStringUntil('\n');
 
 if (inString != null) {
 // trim off any whitespace:
 inString = trim(inString);
 // convert to an int and map to the screen height:
 float inByte = float(inString);
 inByte = map(inByte, 0, 1023, 0, height);
 
 // draw the line:
 stroke(127,34,255);
 line(xPos, height, xPos, height - inByte);
 
 // at the edge of the screen, go back to the beginning:
 if (xPos >= width) {
 xPos = 0;
 background(0);
 }
 else {
 // increment the horizontal position:
 xPos++;
 }
 }
 }


7  Using Arduino / Programming Questions / Re: Can any one help me with this? on: November 14, 2012, 01:13:09 pm
I got this to work. I've never had to install drivers using Arduino on a mac, but that was the issue. I went to sparkfun.com and downloaded the drivers for the ftdi basic.
8  Using Arduino / Programming Questions / Re: Can any one help me with this? on: November 13, 2012, 09:27:09 am
Are you trying to program the Arduino Uno with the LEDs connected?  Sometimes you may need to disconnect everything from the I/O pins so that it doesn't interfere with the uploading of sketches.



I just disconnected the board from the entire schematic and tried to upload the blink program, hoping pin 13 would blink repeatedly. It did not work. So, there is no schematic and the code is the same as the blink code. Upon further troubleshooting, I noticed that the Arduino software performs exactly the same when I completely disconnect the USB and ftdi. It runs through, gives the error message above, and then says "Done uploading.". It would appear it is not the FTDI, but something with either the software or system. I'm running the Lilypad Atmega328, (and tried two different lilypads, so it's not the board). It's also helpful to note, I am not the OP.
9  Using Arduino / Programming Questions / Re: Can any one help me with this? on: November 12, 2012, 11:52:27 am
I'm having a similar error. It reads avrdude: stk500_getsync(): not in sync: resp=0x30
I've tried swapping out the usb cable, and switching board and port connections. I'm running an old operating system, OS X.4. Is it my FTDI that's gone bad?  Just like above, the lilypad is running the last successful upload. It might also be worth noting, the FTDI doesn't recognize if there's no board attached during the upload process. Also, it will blink the red and green LEDs on the FTDI when first plugged in, but no LEDs light up when the program is uploading. If I reset the lilypad, the onboard LED will blink once. I guess that's the bootloader.
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