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1  Products / Arduino Yún / Re: Long lasting connection between Yún and PC on: February 05, 2014, 06:01:18 pm
I've been thinking about this as I'm getting ready to build a robot around the Yún.  My plan is to write some code in Python which handles the sockets and passes the data back and forth to stdin and stdout.  Then I will launch this Python process from the Arduino side using the runAsynchronously() method from the Process class.  Telemetry data will be sent from the Arduino side to the Python process (and ultimately the remote control point) with the write() method, and control commands will be read with the read() method.  You can periodically check to make sure the Python process is still running with the running() method and respawn as necessary.

I will let you know how it goes once I start coding.   smiley
2  Products / Arduino Yún / Re: Yun - Can't turn LED on/off through browser on: January 15, 2014, 05:02:46 pm
Are you sure you uploaded the bridge program to the AVR side?
3  Products / Arduino Yún / Re: help me on: December 09, 2013, 03:59:35 pm
If you applied 12V to the Vin pin, it's a miracle that it works at all.  Which part of the board is getting hot?  C102 and C103 have a 6.3V rating, so it's possible that one or both of them took a beating.  Are you sure everything works on the board?  Sheet 2 of the schematic shows the overall voltage distribution.  The USB hub and ATmega 32U4 are more-or-less directly connected to the Vin pin.
4  Products / Arduino Yún / Re: Tutorial for python on Linino on: December 06, 2013, 03:37:27 pm
Here's a little tutorial on getting into the Yun over SSH:

http://www.homautomation.org/2013/10/01/playing-with-arduino-yun/

Except you will use your SSH client instead of typing SSH at the command line.

5  Products / Arduino Yún / Re: Tutorial for python on Linino on: December 06, 2013, 03:30:27 pm
No, you need an SSH client like putty.  Using the password you configured in the Yun web interface and the "root" username, connect using the SSH client, specifying the Yun's IP address and port 22.
6  Products / Arduino Yún / Re: Tutorial for python on Linino on: December 06, 2013, 03:15:52 pm
If you are new to both Linux and Python, then you have quite a learning curve in front of you.  But learning the world's greatest operating system and programming language can be  lot of fun. smiley  Basically, what you want to do is SSH into your Yun, install an editor you are comfortable with using opkg (if it's not already installed), write your Python script using the editor, save it to a file, then run the program with the "python <filename>" command.  At least that's how I'd do it.  You could also type "python" without a file name and execute Python statements interactively, for the purpose of learning and testing.  Once your script is running the way you want, you can start it from the arduino side if you like using the Bridge library.
7  Products / Arduino Due / Re: Due with Relay Shield on: September 10, 2013, 12:45:07 pm
I have that relay shield.  Judging from the schematic, there are no 5V outputs from the shield connected to Due I/O pins, so it should be safe.  The inputs are optically isolated, so that will protect the Due from any voltage spikes coming from the relays.  Just don't plug any 5V devices into the 7-pin wireless SIP socket, as those outputs would connect to Due pins.

I'll have a closer look when I get home tonight and let you know if I see any problems.
8  Products / Arduino Due / Re: Using Arduino Due's DAC0 to create a variable intensity LED driver on: August 20, 2013, 11:39:07 pm
It's likely that your NPN transistors are acting like switches.  If you want to use a DAC output and have linear control, I recommend using an emitter-follower configuration, something like option B on this page: http://electronics.stackexchange.com/questions/57845/why-would-one-drive-leds-with-a-common-emitter.  Either that or use straight PWM control of duty cycle.
9  Products / Arduino Due / Using a V5 ethernet shield with Due on: August 20, 2013, 10:22:59 pm
I was looking for an ethernet shield for my Due and discovered that only the latest version ("R3" or "V6") has the IOREF sensing and is therefore safe to use.  The official shield is something like $45, but on Ebay there are a ton of older shields for as little as $10.  I picked up one that was billed as being "Mega compatible," and it turned out to be a version 5.  I took a look at the schematic and determined that there was only one place where 5V touches the Due pins:



Chances are that this wouldn't hurt the Due, given the relatively high value of the pullup resistors.  However, I found a convenient place to cut the trace that connects the pair of resistors to 5V and did so:



If you intend to use those Due pins for sensitive analog work, you might also cut the trace between pins 5 and 6 of the resistor network directly above the other cut point.  Otherwise, A0 and A1 would still be connected by 20K of resistance.  None of the trace cutting will affect using the version 5 shield with other Arduino boards, since those pins only connect to the full-size SD footprint, which can't even be populated without desoldering the microSD socket first.
10  Products / Arduino Due / Re: Arduino Due & EasyVR on: August 20, 2013, 04:07:01 pm
As far as I know, the Due doesn't have a software serial library yet.  However, the Due has plenty of hardware serial ports!  You will need to rewrite the code to use Serial1, Serial2 or Serial3 instead.  These pins are found on the "communication" header.  Also, make sure that the EasyVR does not output 5v on its serial line as this could damage the Due.
11  Using Arduino / Displays / Re: how to // #define LCD_RESET A4 in TFTLCD.h ? on: August 13, 2013, 10:17:22 pm
Hi Samond,

Which library are you using with that display?  You say the Adafruit library doesn't work, but you don't say which one you're using.

You could always unsolder that reset pin from the TFT shield and run a separate wire to the Arduino's reset line.

12  Using Arduino / Project Guidance / Re: FS1000A / XY-MK-5V 433Mhz TX/RX Module on: November 06, 2012, 09:12:25 pm
This link may be of some use to you:

http://www.glacialwanderer.com/hobbyrobotics/?p=291

You can use either receiver pin for data, but you need to do some noise filtering in hardware or software because these devices use simple amplitude modulation.  If you are just interested in on/off control and not a serial data stream, you can pair the transmitter with a Holtek HT12E encoder and the receiver with an HT12D decoder.  This will give you 8 bits of address and 4 bits of on/off control.
13  Using Arduino / Sensors / Re: Precalibrated CO2 sensor on: April 21, 2011, 01:24:15 pm
They all run I2C which makes them dead-easy to interface with and I actually put together an application note a little over a year ago showing how to interface with a Arduino:

http://cdn.shopify.com/s/files/1/0019/5952/files/Senseair-Arduino.pdf?1264294173

You are THE MAN!  I just started building an incubator where I have to control CO2 levels.  After researching all of the available sensors, I decided I wanted an IR sensor for maximum life and accuracy.  I bought a K22-PWM from co2meter.com for $65 and have been thinking about the interface.  I used a Bus Pirate (see http://bit.ly/cRzjF2) for initial testing of the sensor over I2C (works great!).  I was about to start interfacing to Arduino when I discovered this thread.  Kudos!
14  Forum 2005-2010 (read only) / Troubleshooting / Re: Wire library and ATmega8 on: June 02, 2010, 11:36:30 am
That's it!  The Wire library by itself wasn't exceeding RAM, but when I add my font tables (declared as integer variables), it was too much for the little ATmega8.  Thanks for your reply.
15  Forum 2005-2010 (read only) / Troubleshooting / Wire library and ATmega8 on: June 01, 2010, 05:38:41 pm
I have an Arduino Duemilanove with ATmega328P, and the Wire library seems to be working fine.  I am using it with the DS1307 library to read the time (see code below).  If I remove the ATmega328P and insert an ATmega8-16P, then the Wire library no longer seems to work.  I don't see any read activity with a logic probe on the DS1307 pins.  Are there any caveats to using the Wire library with the ATmega8?  I can't see any notable differences between the processors in the data sheets aside from memory.  To answer any anticipated questions, yes I did program the correct bootloader and set the proper fuses, yes I did specify ATmega8 in the board setup, and yes I can upload and run other sketches that do not use the Wire library.  

Any ideas?  Thanks.

Code:
#include <WProgram.h>
#include <Wire.h>
#include <DS1307.h>    // written by  mattt on the Arduino forum and modified by D. Sjunnesson
#include <Sure0832.h>

byte csPin = 7;
byte rdPin = 0;
byte wrPin = 6;
byte dataPin = 5;
byte numDisplays = 1;

boolean am;

int num, tens, ones;

Sure0832 LEDmatrix(csPin, rdPin, wrPin, dataPin, numDisplays);

void setup()
{

   Wire.begin();

}

void loop()
{

   LEDmatrix.setCursorPos(0);

   num = RTC.get(DS1307_HR,true);    //read the hour and also update all the values by pushing in true

   if (num > 11)
      am = false;
   else
      am = true;

   if (num > 12)
      num = num - 12;
  
   if (num / 10 == 1)
   {
      LEDmatrix.writeCol(0,0x41);   //manually write a "1"
      LEDmatrix.writeCol(1,0xFF);
      LEDmatrix.writeCol(2,0x01);
   }
   else
   {
      LEDmatrix.writeCol(0,0);   //clear
      LEDmatrix.writeCol(1,0);
      LEDmatrix.writeCol(2,0);    
   }
  
   LEDmatrix.setCursorPos(5);      
   LEDmatrix.writeChar(48 + (num % 10));

   LEDmatrix.writeCol(12,0x66);      // write a ":"

   LEDmatrix.setCursorPos(15);
  
   num = RTC.get(DS1307_MIN,false);  //read minutes without update (false)

   LEDmatrix.writeChar(48 + (num / 10));
   LEDmatrix.writeChar(48 + (num % 10));
  
   LEDmatrix.setCursorPos(28);
  
   if (am)
      LEDmatrix.writeAM();
   else
      LEDmatrix.writePM();
      
   delay(1000);

}


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