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676  Using Arduino / General Electronics / Re: Resistor Size. on: December 29, 2013, 07:21:41 pm
It is the actual size of the LED ,  nothing to do with it's electrical properties.    The common sizes for the traditional basic bullet-shaped round leds are 3 mm  and 5 mm.   
677  Using Arduino / Programming Questions / Re: Arduino windows 8 won't program on: December 29, 2013, 07:15:47 pm
That message would appear to be from the compiler   and not from "programming" ( uploading ? )  your Uno.
678  Using Arduino / Sensors / Re: DS18B20 sensor, datasize on: December 29, 2013, 07:03:58 pm
I think the answers about bits were a red herring.

I agree that there is no obvious reason why that data[] array needs to be 12 bytes,   in your code.  It is likely that the code was adapted from some other code relating to some other device, not relevant to you,  which did provide 12 bytes of data.
679  Using Arduino / Sensors / Re: Why analog read value is fluctuating? on: December 29, 2013, 06:59:33 pm
No, there isn't.    You will always experience fluctuations of one or two counts in analog readings.    That is partly because of the way the A/D converter works,    and also partly because of the way the pot works.   

Because the pot has a moving contact,  even when you are not turning it,   the contact between the two moving surfaces in the pot is varying at the microscopic level,   and this affects the current transmission and the apparent output voltage of the pot.
680  Using Arduino / Sensors / Re: Pressure Sensor Averages on: December 29, 2013, 06:54:28 pm
Do you press on the wall with the same firmness,  every time ?

Unless properly mounted and subjected to pressure in a very systematic and repeatable way,   I would not expect to get the same reading from such a device twice in a row.

681  Using Arduino / Sensors / Re: coulomb counting on: December 29, 2013, 06:50:56 pm
Your problem is always going to be,    getting a detectable response for small currents while still being able to deliver large currents.

What I would be looking to do,   is separate the starter motor circuit from the circuit for everything else.    And then put a 100 amp shunt in the starter motor circuit and a 30 amp shunt ( with a higher mV/A sensitivity ) into the circuit for everything else.

The wiring in every car I have ever looked at,  is already actually arranged to facilitate this.  In my car there are two leads off the positive battery terminal.   One goes straight to the starter motor.   The other one goes to the fuse receptacle.
682  Using Arduino / Sensors / Re: MPU 6050 Sensor Problem on: December 29, 2013, 06:44:41 pm
Quote
I need gyro data as a position to ground.

What is this sentence supposed to mean ?   Try again,  and explain what you want to do with the sensor.
683  Using Arduino / Sensors / Re: Infrared / Optical Sensor Larger Range Calculation on: December 29, 2013, 06:42:24 pm
The problem is not with the "calculation",   that's easy,  it's based on the speed of light.    the problem lies with the actual ability of your LED light to illuminate and detect a return from the target object.
684  Using Arduino / Programming Questions / Re: Help with converting 4 bytes to a long on: December 29, 2013, 02:04:54 pm
The thing you have to be careful about,  is negative numbers.
685  Using Arduino / Programming Questions / Re: Comments & advices about my code on: December 29, 2013, 01:58:58 pm
Quote
To save power when not needed, i added a physical interrupt to disconnect the led.

It's not clear what this means.
686  Using Arduino / Programming Questions / Re: Digital Temperature Sensor - DS18B20. Code does not work on: December 29, 2013, 01:55:23 pm
Pin 3  and  Pin A3   are not the same thing.     That may be your problem.
687  Using Arduino / Programming Questions / Re: Sending Text Message w/GPS Data on: December 29, 2013, 01:53:01 pm
I suggest you get a basic textbook on C/C++ programming,  because you clearly have no idea what you are doing.
688  Using Arduino / Programming Questions / Re: lost among the pointers and structs on: December 29, 2013, 05:15:53 am
If it is an "internal" struct,  it is probably intended that you don't access it directly,    you should probably use
public functions of the class to get the data you want.

However one of the advantages of having your own microcontroller,  is that you can ignore some of this
class encapsulation correctness b/s.
689  Using Arduino / Programming Questions / Re: Does I2C with "repeated start" bits actually work ? on: December 29, 2013, 05:07:14 am
The MMA8451Q  software has the error.

It is in the example software of Freescale's,   in their application note  AN4076SW,  in the .h file for the device.   The 7th item in the enum is missing,   which makes all the enum values > 7 to be wrong.    The enum can be fixed by inserting the 7th element.    Actually,  element 7 is probably the 8th element.

This seems to be a very nice device,   once it actually starts to work.
690  Using Arduino / Programming Questions / Re: Record while checking for condition on: December 29, 2013, 04:16:30 am
check the scope of your variable "rec".
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