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1  Development / Other Software Development / Re: Libraries for controlling DDS RF Synthesizer Modules on: April 22, 2014, 08:34:22 pm
Docedison (or anyone else)

 I see you attached a compressed file with a type .rar file. My older XP machine has an application to unpack and extract such files but my new win 8.1 64 bit laptop doesn't have anything standard to open it. I googled and was overwhelmed with ads and so many different sites offering different programs to download, most at a cost. Is there a safe free version you can recommend for windows 8.1 64 bit?

2  Using Arduino / Microcontrollers / Re: Alternative to 16U2 on: April 22, 2014, 12:15:12 pm

Well there are two different questions going on here. The OP stated he wanted to build his own arduino board and a second topic of quality/usefulness of inexpensive Asian nano/micro/uno boards.

My thoughts are unless one really just wants the experience/educational value of building an arduino from components, it's just not a cost or time effective effort. Better to put the time and effort into a shield or wired board that does something useful or interesting. Even for just bread-boarding it's hard to beat a < $10 Nano board that just plugs into a breadboad and has the usb connector ready to go and can even have it's bootloader updated to the latest optiboot version. And for insertion into a PCB it's hard to beat the $3 pro-minis. I've bought a few of both and seen no problem in quality or performance.

 However that doesn't change my recommendation that a beginner should start off buying one 'real' arduino Uno board, just call it the 'entry cost' to our great community.  smiley-wink
3  Using Arduino / Project Guidance / Re: Green Laser 3VDC Ebay on: April 22, 2014, 11:48:23 am
 In general the 3.3volt current capacity of an arduino boards has a historical problem that we still live with today. The older arduino boards that use the FTDI USB chip used the chips internal 3.3vdc regulator to wire to the shield 3V3 pin and was limited to 50ma or so, and if more was drawn could and would destroy the FTDI chip. Later with Uno board development they installed a proper on-board 3.3vdc voltage regulator and probably can deliver up to 100 ma or better. However the trap is that if any 3rd party shield developer designed their shield board to draw more then 40ma or so and a user installed it on their older FTDI based board, it could damage the users arduino board. Therefore to this day even the current Uno board carries this information on their product description about the shield 3V3 pin:

3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
4  Using Arduino / Programming Questions / Re: Download program in PC on: April 22, 2014, 11:15:14 am
Not the first time that the words 'upload' and 'download' cause problems for posters and respondents to posters. I 'download' programs sometimes from the web to my PC, but the arduino developers decided to use the word 'upload' as the process to move a program from the PC to an attached arduino board. The words upload and download don't intrinsically define the direction of data flow, just as the words send data and receive data for a serial link doesn't explicitly explain the flow direction as both end nodes have the ability to send and rec, just on different pins.

 I've noticed that on SPI interfaces the signal name are explicitly defined, as in MOSI (master out slave in) and MISO (master in slave out). Those SPI guys knew what they were doing when defining signal names.  smiley-wink

5  Using Arduino / Sensors / Re: how to tell variable reluctance sensor on: April 22, 2014, 10:57:25 am

 since I posted the above message  a friend of mine did some digging and found the Post where I must have gotten the diagram from all time ago.

 I had the diagram wrong anyway so if your interested  you should look at this post,157697.0.html

I also attached a correct version of the diagram \
The thing I didn't know about VR sensors is that they are passive, i.e. they done take any voltage in - they  produce a small voltage , I think its a sine wave +/- and the LM393 is used to amplify and turn into 0 or 1's

However , the question still stands, is there an easy way of determining if the sensor is a VR one?
In the above Link , user 'DC42' seems to have know how to tell but never actually mentions how .

 The VR probes I've used at the refinery I worked on were simple 2 wire devices that feed a comparator to give a digital square wave output at a frequency proportional to the speed and number of teeth that the probe was sensing. I believe the internal construction is a magnet with a coil around it, and as a gear tooth passes the sensor face it changes the field of coil causing a change in the sensor output voltage. The sensor output voltage looks like a quai-sinewave and it's voltage increases with increasing gear speed, however once the voltage is above a certain minimum value the comparator doesn't care as it's just switching at zero crossings of the probe's output voltage.

6  Using Arduino / Motors, Mechanics, and Power / Re: Project a solenoid on: April 22, 2014, 10:43:54 am
Another question, how fast is current to fully power solenoid? 30-50ms or it's comprensive of stroke movement?

 It's a function of the induction value of the solenoid coil. Recall the old ELI the ICE man rule, (voltage E leads current I in an inductive reactive circuit, current I leads voltage E in a capacitance reactive circuit), so the higher the inductive value the 'slower' the coil is to respond. But this time probably pails in the 'speed' on having to move the mass of the plunger assembly.

7  Using Arduino / Motors, Mechanics, and Power / Re: Servos were trembling, especially when reaching 100% PWM duty cycle on: April 21, 2014, 03:14:52 pm
Could be a conflict on internal timers used depending on what pins you are using for the servos and pwm fans. Again from the reference:

The Servo library supports up to 12 motors on most Arduino boards and 48 on the Arduino Mega. On boards other than the Mega, use of the library disables analogWrite() (PWM) functionality on pins 9 and 10, whether or not there is a Servo on those pins. On the Mega, up to 12 servos can be used without interfering with PWM functionality; use of 12 to 23 motors will disable PWM on pins 11 and 12.
8  Using Arduino / Programming Questions / Re: PID not fully functioning on: April 21, 2014, 02:55:58 pm
The PID library has commands to set output limits both low and high for that kind of situation, it effectively clamps the output value between two values you set. You shouldn't try or have to do it in your code for every output command you process.

9  Using Arduino / Motors, Mechanics, and Power / Re: Servos were trembling, especially when reaching 100% PWM duty cycle on: April 21, 2014, 02:52:31 pm
You don't 'talk' to servos with analogWrite() commands. You include the servo library and use servo write commands as in the
following example.
#include <Servo.h>

Servo myservo;

void setup()
  myservo.write(90);  // set servo to mid-point

void loop() {}

More info can be found here:
10  Using Arduino / Storage / Re: What happens when a SD card full on: April 21, 2014, 02:03:29 pm
You are right fat16lib, i didn't remember that, physical storage in computers usually come labeled in Gibibit and not Gigabit
Also fat16 formating type, have a limitation of storage per file which i believe is 4GB, so OP you need to make sure that when the file is 4GB you create a new one

Never seen either used, did you mean Gigabytes?
11  Using Arduino / Installation & Troubleshooting / Re: What type of Arduino do I have? on: April 21, 2014, 01:59:24 pm
If you are indeed using a 4-wire FTDI cable then uploads will fail for lack of the DTR/RTS auto-reset feature and you will have to master the 'well timed manual reset' to be able to perform the IDE upload function.

12  General Category / General Discussion / Re: Good practices (Arduino Programming) on: April 21, 2014, 01:56:12 pm
Pass the popcorn, some of the things you have suggested I've seen argued between even experienced programmers, and fall into the catogory of 'personal preferences'. At least that is the impression I've gotten from hanging around here for several years.  smiley-wink
13  Products / The Arduino Starter Kit / Re: Problem with DigitalReadSerial on: April 21, 2014, 12:04:50 pm
Sounds like you two are describing two different symptoms/problems. One is only serial printing zeros the first saying "not response". The first points to a wiring problem or a broken input pin, the second a serial comm problem. Of course the sketch compiles with no errors so the program is not to blame.

14  Using Arduino / Project Guidance / Re: Addressing analog pins on the arduino pro mini on: April 21, 2014, 11:54:36 am
You might just have a bad analog pin. Note that the signal has a pull-up resistor to 3.3vdc at the mosfet, so the signal line will be a high is the pin is open circuit internally in the chip. Have you tried your 3 second test sketch on some of the other analog pins?

15  Using Arduino / Networking, Protocols, and Devices / Re: Arduino Mega I2C without USB - problem on: April 21, 2014, 11:35:01 am
If you are connecting 5.3vdc via the external power or Vin pin then you are using too low a voltage. From the product specs:

The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.
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