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1  Using Arduino / Displays / Re: LCD has strange characters when not lcd.clear() is sent on: December 25, 2011, 04:38:49 am
You have this which does not match the example code or wiring.

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

When I tried to run your code it caused garbage. My LCD is wired per the example and when I changed your code to match it worked.
2  Using Arduino / General Electronics / Re: Termistor on: November 21, 2011, 12:06:15 am
Is a termistor the main part of a Terminator?
3  Using Arduino / General Electronics / Re: Small Arduino Replacement? on: November 20, 2011, 11:53:20 pm
Its rare (if at all) that all three colors of the RGB will be on at the same time.  Mostly just strobing really fast (6 ms on, 1-2 ms off) between colors.  So I don't think that excessive current output with be a problem....

That should be ok. If more current is needed this shift register rocks after that you'd need some UNL chips or discrete transistors.
4  Using Arduino / General Electronics / Re: INA125 Oh crap.... on: November 20, 2011, 11:38:40 pm
If none of the VREF pins are working it's most likely fried. Put a in4001 diode on the board in series with the power supply input to prevent that in the future.

5  Using Arduino / General Electronics / Re: Looking for the right Optocoupler on: November 20, 2011, 10:53:44 pm

If you don't want the line frequency to come through you can rectify the AC and filter it and then with a current limit feed that to about any optocouple for a simple on/off.

There's an application note which may help.

6  Using Arduino / General Electronics / Re: Use Arduino to send email on: November 20, 2011, 10:32:44 pm
You can use an ethernet shield. It's expensive but it will send emails and can email to an sms gateway for text messages.

The less expensive option is to leave the USB connected to a computer and have a program on the computer accept messages and it sends the emails. You can look at the processing language for that.

7  Using Arduino / General Electronics / Re: Looking for a Arduino Mega 2560 development shield... on: November 20, 2011, 10:18:54 pm
I use the same shield as for the Arudino , it fits. It does not cover the extra headers so those are available.

This is a kit that needs soldered. It's effing half the cost of an arduino!

I see several online, I have no clue about them. The sparkfun looks the best.

I've taken to just using my giant and mini bread boards. If I want a permanent solution I'll either buy another unit or find one of the bare bones ones. I was considering a freeduino epic that has no headers or usb but I can buy a whole mega for the same cost.

8  Using Arduino / General Electronics / Re: TIP31A Transistor Help on: November 20, 2011, 10:04:09 pm
If you ever want to drive high voltage and high amps see about getting a few of these as a sample.

I've used them and they're pretty damned tough. It's a low side driver like an NPN transistor but it is designed for logic levels and it's more efficient due to the very low on resistance.
9  Using Arduino / General Electronics / Re: 5V to 12V on: November 20, 2011, 09:51:53 pm
What is the simplest/easiest way to bump 5 volts to 12 volts?

You need to use a separate 12 volt supply. Tie the Arduino ground to the 12 ground  and the transmitter ground then tie the +12V to the transmitter. If you're trying for battery operation you can use a 12volt battery with enough milliamp hours and use it to power the arduino and transmitter. 

10  Using Arduino / Programming Questions / Re: Virtual switch on: July 24, 2011, 12:28:36 pm
Even with the lower current relay you still need the diode or the reverse EMF can fry the arduino
11  Forum 2005-2010 (read only) / Troubleshooting / Re: Getting the Arduino software running on FC6 Li on: June 26, 2007, 11:30:31 pm
Thanks for the link. I did not even know that feature was in Fedora. I'll have to reinstall all of the packages I removed and use that and see if it works. I probably should restore this system to default or just setup another one to write a howto.

I believe the Linux version uses whichever version of Java comes first in your path.  A little Googling reveals that you should be able to use /usr/sbin/alternatives to select your default Java implementation with something like:

alternatives --config java

BTW, you should consider writing up some notes on getting Arduino to work under Fedora on the playground.  The linux page is at: and you could create a link to a Fedora-specific page.  You can register for the playground at:

12  Forum 2005-2010 (read only) / Troubleshooting / Getting the Arduino software running on FC6 Linux on: June 24, 2007, 03:59:49 pm
I am kind of disappointed this didn't work as expected right from the start.
I loath windows so much I got the Arduino because of the Linux IDE.

I found out that Fedora Core 6 does not work with it without some major pain.
I finally tracked it down to the GNU tools java being called rather
than Sun Microsystems java.

I went to the trouble of ripping out all the GNU java tools and all the software dependent on it with yum. There were probably some important items I lost but at this point I wanted to get it working.

Once I'd installed the avr tools
and manually installed avr-libc as there is no current RPM and the included spec file is broken I could get the software  up.

dmesg will show what port the device is on. In my case it's /dev/ttyUSB0

The first time I tried to verify/compile a sketch it bombed with "could not verify size"
The 2nd time it compiled!

In the software it seems to have autodetected all available com ports and I chose USB0 and it's working.  ;D

I'll now have to pick up the shattered pieces of my system and figure out WHY the stupid thing refused to chose the right java software. Then I'll reinstall what I absolutely need to have installed.

Now I need to find a way to make a MSP430 IDE work on Linux and I can scrub Xtra P off my system.
13  Forum 2005-2010 (read only) / Troubleshooting / Re: Programmer not resp. after assigning pin0 on: June 24, 2007, 04:55:02 pm
Can you post a drawing of what you did?  I'd be curious as to what killed the chip.
14  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Digital Pin 6 pullup resistor? on: July 01, 2007, 06:42:28 am
I made a sketch with just a delay in loop(). setup() is empty.

5.11 VDC with nothing connected. 1.74v with an LED and resistor.
The other digital pins read 0

Is there anyway to read what those resistors are set to? I've just gotten mine and have not fully learned the language or capabilities yet.

Ok, I learned how to reprogram the pin and it reads 0. It would be a bit annoying as I don't see a way to set the pin back to an output after having to set it to an input to set that resistor off.

Anyone else tried this - I'm looking for a little more  data to confirm that this problem is in the official bootloader/hardware distribution.

Try this:
Send Arduino a blank sketch. The sketch can do anything else, but shouldn't do anything to pins 0 to 7.

Put a voltmeter between pin 6 and ground to cofirm whether it's at 5 volts.

Post a reply on this thread.


Paul Badger

void setup()                    


void loop()                     // run over and over again
  delay(1000);                  // waits for a second
15  Forum 2005-2010 (read only) / Syntax & Programs / Re: 2D dynamic boolean array on: December 31, 2010, 02:52:03 pm

The bitarray library in the last two links might be worthwhile to look at the source code, it's not an Arduino library.
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