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46  Using Arduino / Project Guidance / Re: Connect 2 or more MPU6050 on board arduino Uno R3 on: February 24, 2014, 01:19:39 pm
Oops, sorry.  My Bad.  6050 is a 3.46V MAX device, so A0 would definitely NOT tie to +5V, but +3.3V.
However, the AUX_DA and AUX_CL are pass-throughs for putting other devices on the same I2C channel (either to talk to the 6050, or the host). And yeah, the pull-ups aren't needed.  Sorry again, was looking at the 6050 datasheet, not the breakout board.
47  Using Arduino / General Electronics / Re: analogRead not showing expected results on: February 24, 2014, 10:54:12 am
To expound upon what Tack is saying, 10K 'marked' resistors don't always measure 10K Ohms (tolerance and temp coeff).  But, Poly and James are most likely the ones with the most appropriate responses (IMHO).
48  Using Arduino / Project Guidance / Re: Second ATMega chip? on: February 21, 2014, 02:12:04 pm
I'm out'a here.

Man are they gonna jump on you.  look up code tags.
49  Using Arduino / Project Guidance / Re: Ballistic Chronograph on: February 21, 2014, 02:08:01 pm
The answer to your question really depends upon what you are going to use for sensors and what you think your sensor path will be.
50  Using Arduino / Project Guidance / Re: How to read power measurement with Arduino analog input ? on: February 21, 2014, 02:00:32 pm
You have chosen well.

Good luck and have fun.
51  Using Arduino / Project Guidance / Re: Square pulses with variable frequency(1Hz-100Hz) on: February 21, 2014, 01:59:15 pm
Other than a learning experience, a terrible waste of a duino.....
How about a 555, some resistors, a cap, and some simple math?
52  Using Arduino / Project Guidance / Re: Second ATMega chip? on: February 21, 2014, 01:54:35 pm
It don't get much more complete than that, or simplier.
Still like to know how he's going to plug that SMT into the breadboard.....
53  Using Arduino / Project Guidance / Re: How to read power measurement with Arduino analog input ? on: February 21, 2014, 01:52:21 pm
Same way you would build a string for serialprint?
Where are you going to put the string? monitor, SD card, LCD, 7Seg LED?
54  Using Arduino / Project Guidance / Re: strange input values in my first helloworld on: February 21, 2014, 01:30:02 pm
Try some smaller resistors and remember that 1) it takes time, albeit a fairly short time, for the ADC caps to charge. that time depends upon the amount of current feeding the analog pins.  you may be sampling before full charge, 2) the value of the resistors change with thier tempreture and thus, supply vayring amounts of current, and 3) you can be picking up some stray volts from surronding electricals and electronics.
55  Using Arduino / Project Guidance / Re: Photosensor activated LED's and Piezo? on: February 21, 2014, 01:22:28 pm
And, one way to gain knowledge is to follow your imagination (until something goes poof...) and another is search and read.

Good luck and have lots of fun.
56  Using Arduino / Project Guidance / Re: Second ATMega chip? on: February 21, 2014, 01:18:56 pm
Then your chip is a Surface mount.  Reread CrossRoads' reply and look up ICSP.  DO NOT attempt to remove the chip. How would you use it in a breadboard setup anyway?
57  Using Arduino / Project Guidance / Re: How to read power measurement with Arduino analog input ? on: February 21, 2014, 01:10:59 pm
I believe the idea is to scale your input voltage to the Arduino analog pin with the voltage divider, such that the input voltage at the analog pin never exceeds the Analog reference which you are using (5V or 3.3V).  The ratio of R2/(R1+R2) gives you the scaling factor (ie: R1= 8K, R2= 2K,  2/10= 1/5= 0.2, so with a maximum of 25V applied to the top of the voltage devider, you would see a max of 5V (25*0.2) at the junction of R1&R2, this applied to Ax would give a value of 1024, using Saravan's 4.883mV, you would calculate 1025*0.004883= 5.000193V, THEN you have to apply the scale factor (0.20) to get back to the actual (approximately) voltage applied to the divider: 5.000193/0.2= 25.00096).  At least I think that's how it works....... fuzzy old fart, forgets a lot of stuff...  

You should also remember that the ADC needs a certain amount of current to charge up the internal caps, so.... you have to limit the total resistance of R1+R2 to keep the conversion time reasonable.  
58  Using Arduino / Project Guidance / Re: Connect 2 or more MPU6050 on board arduino Uno R3 on: February 20, 2014, 11:55:40 am
MPU board 1, tie AD0 to GND (causes board 1 to have an I2C address of 0x68, decimal 104),
                    tie GND to GND of board 1, tie Vcc to Vcc of board 2,
                    tie SCL to XCL of board 2, tie SDA to XDA of board 2,
                    Leave XCL & XDA open, INT depends on whether or not you intend to use it in app.

MPU board 2, tie AD0 to Vcc through a 1k to 10k (your choice) resistor (caused board2 to have an I2C address of 0x69, decimal 105),
                    tie GND to Arduino GND, Vcc to Arduino +5V,
                    tie SCL to Arduino SCL (A4 or A5, don't rember of hand) and through a 4k7 resisror to Arduino +3.3V,
                    tie SDA to Arduino SDA (A5 or A4, don't rember of hand) and through a 4k7 resisror to Arduino +3.3V,
                   INT depends on whether or not you intend to useit in your app.

The stock WIRE lib used A4 & A5 for I2C SCL & SDA. If you want to hook up more than two MPU's, you will need to setup another I2C channel. one way is to initiate another instance of WIRE, using another Analog pin of the Arduino as the SDA for that channel ( and hook up MPU's as above).  Another way suggested is to multiplex the SDA lines with hardware.
This is from memory, but with a little reading, you canget the corrected details. check out the MPU6050 data sheet and the ARDUINO playground.
                 
59  Using Arduino / General Electronics / Re: how to construct this circuit.. on: February 18, 2014, 03:20:59 pm
Mike,
Why?  I/O9 is only used in one of the two circuits.
60  Using Arduino / Project Guidance / Re: Position Locator on: February 14, 2014, 08:50:48 am
"If it happens to be buried, there will be an impact crater ",,,,  and it will be easy to collect most of the peices.... Not too encouraging a project description.

Says the guy named 1-2-3-Splat smiley-grin

How do you think I got the nickname?
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