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16  Using Arduino / Displays / Re: SainSmart 20 x 4 LCD wanting to use I2C from Arduino Uno on: September 25, 2014, 08:38:41 pm
Can't you just let this two year old thread rest in peace?

This is it's third resurrection after the original problem was solved in September of 2012.


Don
17  Using Arduino / Displays / Re: 59 - 09 in LCD and RTC on: September 25, 2014, 11:56:30 am
Quote
If you like the single number '0', '1', '2'...'9' then you will need to clear the whole line prior to writing the new number.

It's simpler than that:

Old:
Code:
    lcd.setCursor(4,1);
    lcd.print(now.hour(), DEC);

New:
Code:
    lcd.setCursor(4,1);
    lcd.print("  ");
    lcd.setCursor(4,1);
    lcd.print(now.hour(), DEC);

Don
18  Using Arduino / Displays / Re: Contrast problem using 1602A LCD over I2C [SOLVED] on: September 25, 2014, 10:42:29 am
Quote
Supplying the incorrect voltage to my breadboard was causing the crazy dim and inverted contrast.   My 5V pro mini was working just fine on this low voltage.   

Let me explain a little more about what happened here.  Not only was your pro mini working on the lower voltage, the LCD module was working as well --- except for the contrast.

The contrast voltage is specified with respect to VCC not GND.  Typically this voltage is around 4.5V less than VCC which would be 0.5V with respect to GND when operating with a 5V supply.  When you operate this same display at 3.5 V the required contrast voltage would then be around -1.0V but the best you can get with your potentiometer is 0v.


Quote
Moral of the story: Breadboard power supplies like the one I was using must be supplied with more than 5V in order to feed 5V to the breadboard.

This is true of virtually all voltage regulator circuits.  There is a minimum input-output differential required for them to function properly.  This differential is typically at least 2 volts but there are 'low-dropout' versions that require less.

Don
19  Using Arduino / Displays / Re: Problem with sainsmart 1602 shield and interpreting the error code. on: September 25, 2014, 09:27:35 am
@Dennis 
You have to highlight the material that is code before you use the '#' code button.

Don
20  Using Arduino / Displays / Re: Problem with sainsmart 1602 shield and interpreting the error code. on: September 24, 2014, 05:38:40 pm
According to sainsmart, that library is required for their display shield to work.

Trying to compile this code without it brings many more errors.

The list exceeds the 9500 character posting limit.

Why don't you post a link to the information about your specific device?  From the clues you have given us this is likely to be some sort of LCD / Keypad shield but we really don't know for sure which one.

Don
21  Using Arduino / Motors, Mechanics, and Power / Re: How can I know the frequency of a RF module of motorized blind ?? on: September 24, 2014, 05:30:38 pm
Getting back  to the original question:

Hello, I would like to know the frecuency of a RF module that its inside of a blind engine.
. . .
My idea is to control the blind with a rf module, but there are two possible frequencies, 315mhz and 433mhz:
. . .
How can I know the frequency of the module thats inside of engine??
. . .

Generally speaking this would depend on the particular unit that you are planning to use and the country in which you plan to use it.

Keep in mind that if you are planning to have your Arduino replace or act in parallel with an existing remote then you will also have to know how the information being transmitted is encoded. In other words knowing just the frequency is not going to help you too much.

On the other hand if you want to use your Arduino to 'push the buttons' on an existing remote then the frequency at which that remote is transmitting really doesn't matter.


Don
22  Using Arduino / Motors, Mechanics, and Power / Re: How can I know the frequency of a RF module of motorized blind ?? on: September 24, 2014, 05:15:20 pm
Quote
# , or there must be a dipswitch somewhere otherwise if a customer bought 10 remote control blinds they could all be on the same channel.
The dipswitch technique for selecting channels is not used for remote control devices incorporating a 'rolling code'.  These devices have each receiver (blind in this case) manually link with each transmitter (remote in this case) once.  Then they automatically keep in sync. 

Don
23  Using Arduino / Project Guidance / Re: Arduino Wifi Shield together with LCD Display Shield on: September 24, 2014, 12:54:57 pm
Quote
The examples page on Arduino.cc of LCD's show that the display needs to use digital pins 5, 4, 3 and 2 for data.
You are interpreting the example incorrectly because the example was not adequately explained.

The LiquidCrystal library can use any available Arduino I/O pin for any of the six LCD signals.  The example just happens to use pins 5, 4, 3, and 2 for data (as well as 12 and 11 for RS and E) but that was an arbitrary choice.  All you have to do is match up the LiquidCrystal lcd(. . . ); statement to match your connections.  Two additional comments in the example would have illustrated this quite well.


Code:
// initialize the library with the numbers of the interface pins
// LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);        // put your pin numbers here

Edit: If you are using an LCD shield then the situation is a bit different.  In this case the pin numbers are fixed because the designer of the shield has chosen which Arduino I/O pins to use.  The choice was arbitrary when he chose the pins but once the shield is manufactured then the LiquidCrystal lcd(. . . ); statement must match that design.

Don
24  Using Arduino / Displays / Re: processing time for lcd on: September 24, 2014, 09:30:03 am
Quote
Do you know about how much time is needed by arduino to process lcd listing?

It's not the Arduino that needs time 'to process lcd listing', it's the LCD controller that needs the time.  The Arduino provides this needed time in the form of a 'delay' and in the case of the LiquidCrystal library this delay is 'blocking' which means that nothing else is done by the Arduino during that time.  The net result is the same and your analysis of the problem may very well be correct.

To answer your question - once the Arduino has sent information to the LCD module it's controller requires approximately 40 uSec to process the information in most cases.  This would be 40 uS for each character.  The Clear display command and the Return home command each require considerably longer, about 1.5 mSec which is one reason to try and avoid using Clear in a fast loop.

To give you some perspective the Arduino typically requires 62.5 nSec to execute a command.  This means that the Arduino could have executed 640 commands while it was waiting for each character in a message and it could have executed 24000 commands while waiting for the display to clear.

I hope I got all my numbers correct.  In any case the basic idea is that the Arduino is very much faster than the LCD.  This is a situation where interrupts might be useful. 


Don
25  Using Arduino / Displays / Re: 1st Attempt.. SainSmart Display on: September 23, 2014, 08:44:39 pm
Quote
Looking for some guidance, please!


This thread is complete since the OP (original poster) stated "
Thanks, my first Arduino Experience is now a success."

You really should start a new thread instead of hijacking this one.

Also - you should highlight the portion of your post that consists of code and then use the '#' code button to make it look like this:

Code:
. . .
void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
. . .

Don
26  Using Arduino / Displays / Re: processing time for lcd on: September 23, 2014, 08:35:14 pm
It looks like every time you go through the loop, regardless of the path, you perform these two steps:
Code:
   lcd.clear();
    lcd.print("3_PHASE INVERTER");
Since the information doesn't change it should be written to the LCD once, in setup().  Also, you don't need to clear the LCD since that is done during it's initialization.

In your loop make sure that all of the messages for the second line are the same length.  This way you don't have to clear out the old message - you just overwrite it with the new one.


Don
27  Using Arduino / Project Guidance / Re: Push button mechanism on: September 22, 2014, 10:45:55 pm
Quote
  Before you start ranting about how you meant this and you meant that keep in mind that my correction was about the colors of the wires and not about the other material. 

Quote
  The neutral wire is not white.
Quote
  None of the live wires are black and the black wires are in fact neutral.

Promptly dismissed by the wire color reference table in the link. Not worth discussing.
. . .

The complete quotes would be:
"Most countries:  The neutral wire is not white."
"Many countries:  None of the live wires are black and the black wires are in fact neutral."

These are absolutely supported by the wire color reference table in the link.

Don


28  Using Arduino / Project Guidance / Re: Push button mechanism on: September 22, 2014, 10:33:04 pm
. . .
Well.  I got you all on this one. 
220 does not have a neutral.   it is TWO hots
we are so wrapped up on the one hot, one ground for 110VAC, that we sometimes overlook the fact that 220 does not have a neutral.
. . .
Unless you happen to live in the UK.

Don
29  Using Arduino / Project Guidance / Re: Push button mechanism on: September 22, 2014, 09:06:18 pm
You have posted a link which supports my statement and refutes yours.

Your statement:  "
As a starting point I will point out that normally the Neutral (white) wire is never switched."
Most countries:  The neutral wire is not white.

Your statement:  "
Any wiring changes to accomodate switching are done to the HOT (Live) (black) wire."
Many countries:  None of the live wires are black and the black wires are in fact neutral.

Before you start ranting about how you meant this and you meant that keep in mind that my correction was about the colors of the wires and not about the other material.


Don
30  Using Arduino / Motors, Mechanics, and Power / Re: How can I know the frequency of a RF module of motorized blind ?? on: September 22, 2014, 05:06:11 pm
Quote
Can you tell the OP how the device linked can tell him the frequency of the signal used in his blinds ? ( I can't)

It's essentially a SDR (Software Defined Radio) and it most certainly can be configured as a scanner.

Don
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