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1  General Category / General Discussion / Re: NavSpark: 32-bit Arduino-style device with built-in GPS for $19 on: July 30, 2014, 06:52:41 am
You might get a more detailed answer on pluses and perhaps minuses from users at the navspark site, which has a forum: http://www.navspark.com.tw/.  From the specs, the navspark has one hardware uart that can do read/write, and another than only do write, so you could hook up the modem for the read/write port, and hook up a display either to the write only uart, or via spi (it doesn't list i2c).

Note, the indegogo campaign that was mentioned at the start of this thread is no longer active, but it was successful in raising money, and the company now sell the navspark's from their store.
2  Using Arduino / General Electronics / Re: Arduino Header Cables 2F to 1F on: July 29, 2014, 05:30:27 pm
I suspect most of us just slice wire in the middle, and connect what we need, using solder to make a permanent connection, and putting heat shrink material around the joint and shrink it like zaxarias's post.

But if you are still a solder newbie, you can get cold splice wire taps that allow you to connect cables without soldering (you do need to use enough force to do the splice with large pliers).  Adafruit sells these: https://www.adafruit.com/products/1494, but you probably can find similar things elsewhere.  Note, you want to buy splices for the size of wire you are using.  The Adafruit version can do 22-26 gauge wire, which typically matches what most people use.

Alternatively, if it is power or ground wires, you can use standard breadboards, and they have red/black columns that allow you to plug in separate wires to the board.  Even if they aren't power/ground wires, you can plug up to 5 wires into a row on the breadboard, and they are are connected.  You do have to make sure sure if you are driving signals through the wires, that the total current is less than or equal to the amount the microprocessor can send through a given signal pin.  Here is a tutorial on breadboards: https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard

If you want to start making your own wire that are custom sized, you can get crimp connectors that you can attach to stranded wire.  I've used the connectors from Pololu.com: http://www.pololu.com/category/39/cables-and-wire.  I find crimping the female end on a little challenging with just needle nose pliers, and one of these days I need to get a proper crimping tool.
3  Using Arduino / Installation & Troubleshooting / Re: Intel Galileo Dismal Speed on: July 29, 2014, 07:20:26 am
As I understand it, the Galileo uses a Cypress chip to do the I/O via the i2c bus.  The default I2c is 100Khz.  There are faster i2c buses (fast mode at 400Khz, high speed mode at 3.4Mhz, fast mode plus at 1Mhz, and ultra fast mode at 5Mhz)  A glance at the datasheet (http://www.cypress.com/?docID=31413) shows that it might be able to run in Fast mode (400Khz).  Since I don't own a Galileo, I have no way of knowing if there is a way to switch to Fast mode.  Typically most Arduinos only run i2c at 100Khz.

When I learned that Galileo used i2c for all gpio, I instantly lost any interest in the chip, as it could not power ws2812 (neopixel) leds which need to run at 800Khz.  From the outside, it looks like somebody in Intel said, do an Arduino compatible that runs on an Intel chip, and the poor design team had to cobble up something that could run simple Arduino programs.  I would imagine the design team had to use an off-the shelf chip and they weren't able to fab a separate chip with better GPIO support.  So they used i2c to run the I/O.
4  Using Arduino / Project Guidance / Re: Wireless Network Module for Arduino Nano v4 on: July 24, 2014, 06:51:08 am
Well, the connection between the Arduino and Android devices already uses a wireless network (i.e. bluetooth).

 If by wireless network, your teachers mean wifi like is used for the video, it is possible, but it will add to the cost and you will need to learn a lot about wireless network programming.  This may be what your teachers are trying to guide you towards, learning to research and create your own programs, rather than just following somebody else's instructions blindly.
5  Using Arduino / Displays / Re: 40 pin extension cable on: July 24, 2014, 01:16:08 am
Consider using an i2c or spi terminal that reduces the number of wires to 4 (for i2c) or 6 (for spi).  With 8 or fewer wires, you can use an 8P8C (RJ-45) connector and use shielded cat 5 or cat 6 cables for the data.  You probably don't want to go more than a few feet with normal i2c/spi connections.

If you need longer runs, you probably want to put a microprocessor with the display and send serial data back/forth using RS485 to provide error checking on the 2 serial (RX/TX) lines.
6  Using Arduino / Project Guidance / Re: Video encoding decoding on: July 24, 2014, 01:02:22 am
At 50K, you will not be able to hold a single frame in any of the AVR based Arduinos (Uno, Leonardo, Mega, etc.).  You will be able to hold just 1 frame in the Arm based Teensy 3.1, Due, and DigiX.  So if you need a converter, that is just impossible.  In addition, if you need to read 50K at 30 times a second, you will run into speed issues, since the processors aren't that fast.

Generally to handle video, you need to move up to the SBC (single board computers) that run at higher clock rates, have much more memory.  Depending on what you are doing, hardware floating point may also be needed.  So look at Rasberry Pi, Beagle Bone Black, pcDunio, etc.
7  Using Arduino / Project Guidance / Re: Help Controlling a Camcorder (non-LANC capable) on: July 23, 2014, 01:14:33 am
Well another way is to program a bunch of servos so that push the desired buttons at the appropriate time.
8  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.
9  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
10  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.
11  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.
12  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.
13  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.
14  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.
15  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.
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