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1  Using Arduino / Project Guidance / Re: Help Controlling a Camcorder (non-LANC capable) on: Today at 01:14:33 am
Well another way is to program a bunch of servos so that push the desired buttons at the appropriate time.
2  Using Arduino / Project Guidance / Re: Sending a signal through a cable on: July 22, 2014, 10:47:00 am
I would think using cat 5/6 ethernet cables would be better than using usb cables, since these cables are made for going distances and have 4 pair of stranded wires inside.  You can either cut up an existing 6foot/2m cable to solder individual wires or you can get breakout boards for cat 5 or 6, such as [ur]https://www.sparkfun.com/products/716[/url] + https://www.sparkfun.com/products/643.
3  Using Arduino / Project Guidance / Re: Sending a signal through a cable on: July 19, 2014, 01:24:45 am
Another thought if you were willing to live with i2c distances (something like 2m, but I don't actually recall), Adafruit sells a 16 channel i2c PWM controller that would off-load doing the PWM processing: https://www.adafruit.com/products/815
4  Using Arduino / Project Guidance / Re: Sending a signal through a cable on: July 19, 2014, 12:59:40 am
One way to solve the problem for longer distances is put a microprocessor on the other end, and hook both up with RS485.  Then on the first processor, it just sends down requests (turn on PWM to this frequency, turn it off, turn on led, etc.).

I would use a microprocessor with serial support on each end, and not something like ATtiny85's.  That way, the RS485 handles error correction, etc. and you are not sending PWM signals down the line continuously.  You don't necessarily want an Arduino development system on each end.
5  General Category / General Discussion / Re: Is it possible dynamically create the name of a function? on: July 16, 2014, 04:46:35 pm
Well you can't do this dynamically in a compiled language like C/C++.  You can do it easily in dynamic languages like perl, python, lisp, etc.  However most of those languages won't run on Arduinos.

Now, you can use the class facility of C++ to tie functions to the class (note, I'm typing this free hand, and I am more of a C programmer rather than a C++ programmer, so I may make some mistakes in grammar):

Code:
class MyClass {
private:
  int data;
public:
  MyClass (int i_data) { data = i_data; }
  ~MyClass () {}
  int get_value (void) { return data; }
  void set_value (int i_data) { data = i_data; }
  int increment (void) { return ++data; }
  int decrement (void) { return --data; }
};

MyClass foo (0);

Now, you can dynamically allocate classes, but you have to make sure when you are done with the class, you free it, or you use higher level methods that involve garbage collection of class data to free the data when no references to it exist.
6  General Category / General Discussion / Re: Compilation on: July 16, 2014, 04:35:55 pm
I did a summer exchange program in 1978, and I would often have to toggle in the PDP-11 bootloader using 3 finger octal on the front panel (the PDP-11 instruction format lent itself to using octal, since most of the register fields were 3 bits, and the top bit in the 16-bit word indicated whether the instruction was byte oriented or 16-bit word oriented.

I recall recently somebody did a boot of an Arduino class machine, manually setting the clock/data bits by hand toggle switches in setting up the SPI transfer used by the USP.

And back in the day, we didn't have keyboards directly connected to the computer or screens.  I've programmed with punch cards, including 'patching' them using scotch tape and an exacto knife.  I've also programmed via ASR-33 teletypes, and have feed programs in via paper readers on the ASR-33.
7  General Category / General Discussion / Re: Compilation on: July 15, 2014, 02:13:08 pm
You can find some of the stuff for Fortran for the 704 (which is generally considered the first complete compiler in the modern sense of the word) here: http://www.softwarepreservation.org/projects/FORTRAN/.

I recall when I was at the University of Minnesota in 1975-1979, there was a book on the history of 10 languages.  I suspect by now, the book is long out of print, but perhaps now.  Given it was 35+ years ago, I may still have it somewhere (I recall it was one of the books I kept), but I doubt I could find it.
8  General Category / General Discussion / Re: Compilation on: July 12, 2014, 09:47:54 am
As others have said, you have cross compilers, which is a compiler that runs on one system and generates code for another system.  In fact, when you use a microprocessor with Arduino libraries, you are using a cross compiler, where the compiler runs on the x86 and generates AVR code (or ARM code in the case of Teensy 3.x/DigiX/Due).

When I worked at Cygnus Solutions, which used to do GCC/GDB ports for new chips, we had a third option that we called Canadian cross compiler, where you are building the compiler on one system (such as Sparc Unix at the time), so that the compiler would run on a second system (such as a Windows system running Cygwin), and the compiler would be a cross compiler for a third system.  At the time we created the setup, Canada had 3 political parties that were more or less the the same size and the VP of software engineering had been born in Canada.
9  Using Arduino / General Electronics / Re: [SOLVED] Using analog pin as digital pin on: July 11, 2014, 06:46:15 am
In terms of the original question, on some processors, there are some analog pins that cannot be used for digital pins.  For example, the Nano brings out pins A6/A7 that are analog input only.  Similarly on the Teensy 3.1, pins A10-A14 are analog input only.
10  Using Arduino / Microcontrollers / Re: ATmega2560 is little endian or big endian? on: July 09, 2014, 04:16:11 pm
I wonder does PDP_ENDIAN derive from DEC PDP11 mini-computers. We had one in work with a HUGE 10MB drive.

More interestingly how can there be three types of endian-ness?

...R
Yes.  The PDP-11 floating point format swapped the bytes in each of the two 16-bit words, but the words themselves were not swapped:

If you do:
Code:
unsigned long a = 0x01020304U;

the value with be bytes 4, 3, 2, 1 if you look at them individually.  On a big endian system, the bytes would be 1, 2, 3, 4.  On a mixed endian system like the PDP-11 floating point format, the bytes would be 2, 1, 4, 3.
11  Using Arduino / Project Guidance / Re: Arduino Pro Mini 5V vs. 3.3V on: July 07, 2014, 12:02:25 am
While many of the newer sensors are 3.3v only (or even lower voltage), if you are running lights like ws2812 (adafruit neopixels), these want 5v.  I find many of the 16x2 lcds also seem to want 5v.  Hobby motors tend to run better at 5v than 3.3v, so you can get by with only one power supply instead of two.
12  Using Arduino / General Electronics / Re: Connecting a 2x9 2.54 mm camera to a breadboard on: July 06, 2014, 11:45:22 pm
The Rasberry Pi has 2 rows of 13 pins.  So you can find various breadboards that take the 2 rows of 13 pins, and bring them out to breadboard fashion.  You would only use 9 of the 13 rows, and ignore the printing for the pins.  For example, here is the Adafruit Pi T-cobbler: https://www.adafruit.com/products/1105.

Adafruit also has 3 perma-proto boards with 13 pins for the Rasberry Pi connector if you want to solder things down:

With these perma-proto boards, you would need to order the cable as well (the cable comes with the T cobbler board): https://www.adafruit.com/products/862
13  Using Arduino / General Electronics / Re: Being picky, on: July 06, 2014, 11:26:46 pm
Or RJ-11, RJ-12 connectors used for phone cables in the US, or RJ-45 connectors commonly used for ethernet..

So-called "RJ-11", "RJ-12" or "RJ-45" connectors, since "RJ" is a standard, not a connector.   smiley-grin

Well yes, but I thought RJ-45 was more meaningful to the average person than say 8P8C. 
14  Using Arduino / General Electronics / Re: "Dupont" Male-Male jumper wires at reasonable prices, and pick own colors? on: July 06, 2014, 10:04:28 am
Rather than get pre-made dupont wires, make your own.  You can either get pre-cut wires with given ends of different colors, or just get the crimp connectors, and use your own colored stranded wire to make cables with the right number of connections, and the appropriate color.  Here is where I buy the crimp terminals: http://www.pololu.com/category/70/crimp-connector-housings

Note, I find it much easier to attach the male crimps than the female.  Note, I haven't bought the crimp tool, I just use needlenose pliers (which may explain why I have problems making the female connection crimps).
15  Using Arduino / General Electronics / Re: Help me find these connectors... on: July 06, 2014, 10:00:00 am
I'm not sure about the connectors you show, but here is one set of locking connectors.  I would suggest getting the kit at first, and then if you find you are using 3 pin or 4 pin connectors, you can order the pins that you find you are using.  One note, these headers work best if the male end is soldered to perfboard.  http://www.dipmicro.com/store/SET-HDR

I find myself building custom cables with connectors from pololu.com, but these aren't locking connecting: http://www.pololu.com/category/70/crimp-connector-housings

Another idea is to use audio connectors (2.5mm or 3.5mm, 2-4 wires), such as: http://www.ebay.com/itm/351099036406?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Or RJ-11, RJ-12 connectors used for phone cables in the US, or RJ-45 connectors commonly used for ethernet..
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