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721  Using Arduino / Project Guidance / Re: How to avoid arduino from starting over each time I unplug it. on: January 09, 2014, 11:47:41 pm
May i ask as to why you need to unplug it?...

A button to shut it down would be an idea, and then increment the eeprom a byte at a time to store the location until you hit the end and begin at the start, it would take many many years to wear out the eeprom like that (wiping the last value to 0 so you can search)

another option would be to save the location onto an SD card on an Ethernet shield and use a jump/goto to carry on where you left off.

722  Using Arduino / General Electronics / Re: ON/OFF circuit when it receive 3v signal. transistor? relay? on: January 09, 2014, 11:38:09 pm
0.6v is enough to make the transistor conduct.

you may need to place a diode or 2 to drop the voltage to near 0v   to prevent the transistor switching on with 1v.

723  Using Arduino / General Electronics / Re: ON/OFF circuit when it receive 3v signal. transistor? relay? on: January 09, 2014, 10:59:22 pm
is the signal digital? 3v on 0v off?

if so yes a transistor will do the job, you may have issues if it's a varied signal and you'd need a schmitt trigger to give a clean transition.
724  Using Arduino / General Electronics / Re: A capacitor is charged and discharged every 0.01 s on: January 09, 2014, 10:07:54 pm
Yes  smiley-confuse

Only did it the once though!  smiley-cry
725  Using Arduino / General Electronics / Re: A capacitor is charged and discharged every 0.01 s on: January 09, 2014, 07:56:32 pm
This site frequently use terms such as "explode" and "go on fire" or "burst into flames"

Having been professionally involved in the electronics game in one sense or the other for almost 60 years I have experienced capacitors "popping", "bursting" or "leaking";  resistors "smoking";   semiconductors "popping" and "smoking" and various components glowing rather well  --  but  NEVER "exploding", "going on fire" or "bursting into flames"

I fear there are too many out there who are either overly cautious or trying to scare the living daylights out of those who wish to learn.

So, FEAR NOT, exercise caution, destroy a few components, be prepared to turn off the power when the magic smoke starts to appear, but, most of all,  have FUN experimenting !!

That's true... but you know what you're doing, tell me what happens if you use a 5v rated cap in a 12v circuit like some here would and do....
726  Using Arduino / General Electronics / Re: Electronics current rating and Wire size question on: January 09, 2014, 07:52:58 pm
Hi! Im just wondering why a small Mosfet legs can handle 100A+ but wires needs to be very big to handle the same current?

Wires ard made up a finer twisted copper wire, the legs on a transistor are solid so there's more area for the electrons flow but even so a transistor can get very hot without heatsinking ....
727  Using Arduino / Motors, Mechanics, and Power / Re: Control 220v home appliances with Arduino. on: January 09, 2014, 07:48:34 pm
A safer option (if you still want to proceed).

Use an old power supply and remove the rectifier circuit so you end up with a low voltage AC, use the breadboard and learn to control low voltage AC... a small bulb rated for your supply will allow you to learn safely and when and only when it's working....

Build it, test with low voltage ac... if success wire up the 240v mains to it, hide it away in a non conductive case, stand well back, maybe a prayer (if religious) and throw the power switch lol
728  Using Arduino / Motors, Mechanics, and Power / Re: Maximum relays able to be controlled by Uno on: January 09, 2014, 07:40:45 pm
A 7hc595 shift register will control 8 relays, 2 of them chained together  will give 16 outputs (or higher still with 3 or more)

Easy (3 pins to control hundreds of relays)
729  Using Arduino / Programming Questions / Re: Resetting Arduino Uno By Serial or when a method is finished on: January 09, 2014, 09:14:41 am
does the reset switch pull low or high?

if so, you could get the soldering iron out and do a hardware reset from a digital pin.
730  Using Arduino / Installation & Troubleshooting / Re: Awe Crap, did I fry it? Oh btw, Hello! on: January 09, 2014, 12:41:29 am
Just look on ebay for some cheap clones and use them ... as long as the board does not say made in Italy you're good... use an uno untilyou get the hang of it ..
731  Using Arduino / General Electronics / Re: How do I amplify an IR transmitter? on: January 09, 2014, 12:15:59 am
If you could house an array of  IR leds inside a a reflector to focus the beam you might have more luck..

Or you'd have to find a nice (watt range) IR led and focus it.

Failing that, hide the device and use a radio to activate it... but you'll be left with working out the tv codes to control the tv.

732  Using Arduino / Programming Questions / Re: Sound Controlled lights on: January 08, 2014, 09:32:44 pm
i am not new to arduino  

Don't take this the wrong way but with only 6 posts on the Arduino forum it is hard to believe the above  statement.

Don't take this personally but what has post count have to do with experience?
733  Community / Bar Sport / any android java programmers here? on: January 08, 2014, 09:00:45 pm
I signed up to a java forum but no reply...

Basically I'm using the async threading class, the async is called onCreate then executed it works but as soon as the app loses focus and the socket seems to be killed.

Anyone know how to restart the thread when the app is brought back into focus? (Ie onStop) obviously when the app is destroyed and run again it works..

I'll jump on the desktop and post the code...


734  Using Arduino / Programming Questions / Re: How to exit loops on: January 08, 2014, 08:54:56 pm
735  Using Arduino / General Electronics / Re: Sharing Voltage/Current on: January 08, 2014, 07:18:53 pm
You should be fine with what you plan (providing there's no more heating elements)
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