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556  Using Arduino / Programming Questions / Re: What does the "?" and ":" do in this Code on: December 18, 2013, 10:23:03 am
Really cjdelphi?

How do I know what variable gets assigned to in your syntax?
What if you want to assign to a variable that doesn't show up anywhere else in the expression?

i.e.
Code:
y = (x>10)?(30):(40);

Your syntax is the one that makes no sense.
557  Using Arduino / General Electronics / Re: Calculating inductance on: December 18, 2013, 10:00:51 am
The impedance is:
Z=2*pi*f*L

so if you want the inductance at a given impedance:

L = Z/(2*pi*f)

In this case:
16/(2*3.14159*1000) = .00255

so .0033 is the closest standard value.
558  Using Arduino / Project Guidance / Re: Fastest possible search in small arrays with different methods on: December 17, 2013, 05:47:12 pm
holmes4:
If addr is the correct type, the sizeof() is not required and will in fact cause problems. The compiler is smart enough to know that when using pointer arithmetic the jump is scaled to the size of the array, so if you add 2 to a pointer it will point to the second object whether a byte *, long * or float *.

559  Using Arduino / Project Guidance / Re: Fastest possible search in small arrays with different methods on: December 17, 2013, 05:10:12 pm
wildbill:
From the OP:
Quote
The code example below is only showing test data and not real values. Worth to mention the arrays only hold around 60-80 values each.

You might try a large switch/Case. If it implements as a jump table it could be pretty fast.

You might try precalculating the indexes for the binary search and use an if/else chain to figure out the starting point for binary search.  (Or use the top 3 bits to index into a table).
560  Using Arduino / Project Guidance / Re: Fastest possible search in small arrays with different methods on: December 17, 2013, 04:40:56 pm
Sedgwick "Algorithms in C" is the the bible here. Binary search should only take log(N) + 1 searches.

You might try a tree approach with left and right branches, with each node a struct with the value of the second array. That way, when you find your data, you have what you need.
561  Using Arduino / Programming Questions / Re: Serial Monitor won't print values inside loop on: December 16, 2013, 06:51:09 pm


You can simplify things by calculating prev - now and adding 360 if it less than zero.

ie
Code:
goal = degree_prev - degree_now

goal = (goal >= 0) ? (goal) : (goal + 360);

562  Using Arduino / Programming Questions / Re: Serial Monitor won't print values inside loop on: December 16, 2013, 06:16:10 pm
I don't think this is your problem, but you don't want an else if with only two cases, an else will do fine. I think two that braces are better style when using else-ifs.
563  Using Arduino / Programming Questions / Re: Invalid operands of types... on: December 13, 2013, 01:26:45 pm
No but if you have a*b where b is a pointer, you can choose between two errors. Either an invalid type for multiplication, or a missing operator between two compatible types.
564  Using Arduino / Programming Questions / Re: Automatic generate source code on: December 13, 2013, 10:06:28 am
Not an arduino solution, but the picAxe has Logicator which is a flowchart based language.
565  Using Arduino / Programming Questions / Re: Invalid operands of types... on: December 13, 2013, 10:05:18 am
This is an interesting case of parsing. since the *newAngle would make sense, it could also have complained about a missing operator.
566  Using Arduino / General Electronics / Re: figuring out resistors for SMA on: December 12, 2013, 04:35:57 pm
Don't worry, Hilukasz, it happens to all of us. I was in a meeting where I questioned whether a smallish 50 ohm termination resistor could handle the power required since it had -5 V on it. The reply was "It's OK, it's digital!"
567  Using Arduino / Project Guidance / Re: constant stream of bits on: December 12, 2013, 04:15:27 pm
10MB/s with a simpleminded program might be hard, but in general this would be easy.
568  Using Arduino / General Electronics / Re: figuring out resistors for SMA on: December 12, 2013, 04:08:05 pm
.4*.4*22 is 3.5 W, so you need a pretty big resistor to handle the power.
569  Using Arduino / Project Guidance / Re: GPS Tracker for Camera on: December 12, 2013, 03:14:38 pm
How far away are you from the camera?

Check out the GPS tracking dog collars for a ready-made solution.
570  Using Arduino / Programming Questions / Re: Mega Flash Programming on: December 12, 2013, 10:31:01 am
Are you talking about the EEPROM? It is user accesible at runtime.
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