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1  Using Arduino / General Electronics / Re: Simple question about ProtoShield on: Today at 04:51:21 am
I just don't see how they are connected together. 

Does it matter?

In multilayer PCBs a lot of the traces are invisible. All that matters is that they're connected (which a few seconds with a multimeter will prove).
2  Using Arduino / Microcontrollers / Re: ATtiny85 Master and Slave communication with I2C on: Today at 01:57:17 am
Great, could you write please the fuses you used to enable 16mhz on attiny85?

It's in the datasheet.
3  Using Arduino / Microcontrollers / Re: How to program multiple Arduino Nanos simultaneously on: July 23, 2014, 12:55:12 pm
Short answer: No.

4  Using Arduino / General Electronics / Re: ADC false readings on: July 23, 2014, 10:25:26 am
The voltage across the sense resistor, AND the output of the OP amp seem steady according to my multimeter.

Mutlimeters are no good at measuring signals that wobble. I bet if you connect it to an oscilloscope you'll see something different.

5  Using Arduino / LEDs and Multiplexing / Re: Show on 8x8 led matrix a stored message according to a keypad input on: July 23, 2014, 10:20:04 am

6  Using Arduino / LEDs and Multiplexing / Re: WS2801 Led strip Color Range on: July 23, 2014, 08:30:05 am
can you reccomend a better addressable strip?

I don't know any.

You could try toggling between (0,0,0) and (1,1,1), that would give you half the brightness.

7  Using Arduino / Microcontrollers / Re: ATtiny85 Master and Slave communication with I2C on: July 23, 2014, 08:09:38 am
The only explanation for that is a problem with the I2C library.
8  Using Arduino / LEDs and Multiplexing / Re: WS2801 Led strip Color Range on: July 23, 2014, 08:06:02 am
That looks about right.

(1,1,1) is quite bright, yes. There's not a lot you can do about it when you're using 8-bit PWM (eg. the WS2801).

9  Using Arduino / Microcontrollers / Re: Emulate/Simulate an 1-Wire device With AVR on: July 23, 2014, 08:03:18 am

I want to make an ATmega32 AVR microcontroller behave like a DS2401 (1-Wire Silicon Serial number). Is that possible?


How can I do it?
10  Using Arduino / General Electronics / Re: ADC False Readings on: July 23, 2014, 05:22:07 am
The op amp will give me a steady voltage of lets say 1.30v, the counts should be at 266, but the ADC will read +-20-30 counts off,


When I try to feed my A0 pin with an external power supply @ 1.30 volts, my counts are exactly where they should be.

There's a clue.

I can't seem to figure out the problem here. I have placed the traditional .1uf caps from vcc to gnd, and from A0 to gnd. But I never seem to be able to achieve the value that it should be at. Any help would be greatly appreciated. Thanks.

Sounds to me like you need to stop fiddling with the Arduino and start fiddling with the op-amp instead.
11  Using Arduino / General Electronics / Re: measuring curren from a chip... on: July 22, 2014, 12:15:19 pm
bascially i added one point of shunt resistor to GND of series with pin of 5V of LM7805..would that method be ok to know the overall current consuming in chip...o

That makes no sense at all. You're measure how much current goes through a resistor to ground.

Good for confirming Ohm's law. Useless for finding out how much current your circuit uses.

12  Using Arduino / General Electronics / Re: Power Supply questions on: July 22, 2014, 12:05:33 pm
Note that this is an isolated supply, but the output terminals mustn't go too far from
earth (the input-output isolation is tested to 3kV, but output-earth isolation is only
tested to 500V)

Unlikely to be a problem ... but it might be worthwhile tying "V-" to the ground terminal with a little wire jumper - give it a solid reference point.

(ie. The screw terminal for earth will have two wires in it, one to mains ground and the other to "V-")

This trick can also save you from pain if you're using multiple power supplies and you forget to connect all the grounds together (although it shouldn't be a substitute for doing that - belt+braces...!)

I would get shocks from my bench supply because i leave  Jumper wires sticking out of the Ground rail on the breadboard. Every now and then my elbow would brush across one and i would feel a sharp stinging sensation. It took a few times  to realize what was going on.  Probing V- wrt ground shows about a 30 volt difference :/.

This trick will help with that, too...

I've seen differences of much more than 30V. In theory you're safe to grab the wire because it's floating but yes, it will tickle you if you brush it lightly.

nb. Connecting V- to GND will take away some of that safety. If there's bare V+ wires lying around you might be better off not doing it. I don't think it's a problem for 5V/12V supplies but ... it's your decision... smiley

The GND of Arduinos is usually connected to mains ground via your PC and I suspect you've touched Arduino 5V wires many times.
13  Using Arduino / General Electronics / Re: Power Supply questions on: July 22, 2014, 11:24:04 am
I have a couple questions regarding it: the power supply has a +V and -V as well as ground. does it matter what V i use?

I think it's just weird labeling and "V-" really means "GND".

The first thing you should do when it arrives is probe it with a multimeter.

14  Using Arduino / General Electronics / Re: Mega2560 max current question........... on: July 22, 2014, 11:19:06 am
I think it means "don't leave any of them unconnected".

15  Using Arduino / General Electronics / Re: -First build- Am I Buying the right stuff? on: July 22, 2014, 11:09:37 am
Another question is do the pro mini have same amount of pins? I have only 13 free in this build...

Most Pro Mini's actually have more pins than an Arduino Uno.

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