Hi There!  I want to scroll the text on the LCD.  I am using the below sketch but its giving error "cannot convert 'String' to 'char*' for argument '1' to 'void marquee(char*)". What I have to do to get this worked?

Thanks.

Code:

#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
const int numRows = 2;
const int numCols = 16;
String stringOne;
String stringTwo;
String stringThree;
void setup()
{
  // set up the LCD's number of columns and rows:
  lcd.begin(numCols, numRows);
}
void loop()
{

  stringOne = "HELLO WORLD!!";
  stringTwo = "hello world!!";
  stringThree = stringOne + stringTwo;
  marquee(stringThree);
  delay(1000);
  lcd.clear();
}

// this function uses scrolling to display a message up to 32 bytes long
void marquee(char  *text )
{
  int length = strlen(text); // the number of characters in the text
  if(length < numCols)
    lcd.print(text);
  else
  {
    int pos;
    for( pos = 0; pos < numCols; pos++)
      lcd.print(text[pos]);
    delay(1000); // allow time to read the first line before scrolling
    while(pos < length)
    {
      lcd.scrollDisplayLeft();
      lcd.print(text[pos]);
      pos = pos + 1;
      delay(300);
    }
  }
}

Hi There!

I have moved my project to standalone board of Atmega 8.  During this process, I had to load boot loader on the atmega 8.  Everything works as expected except the 10 seconds delay at start up when powered on.   Is there a way to minimize this delay?  I don’t need in system programming option.  While googleing I have found opti boot may fix this issue, is that an option?

Thanks in advance,

No.. No.. What I meant was the RC  circuit ( .01 mfd and 39R in series) in the link you mentioned is a snubber. So you no need to add anything if you are using the same circuit.

You need to add a snubber circuit if you dealing with inductive load.  The resister and capacitor in series across the load in the first circuit is nothing but the RC snubber.

Thank you!

Thank you very much for your quick reply.  So a 150 Watt 220 V to 110 V converter is best bet?

Hi There!

I need to buy an 220V AC to 110V AC converter for my Xbox adapter. Only DC power rating is mentioned on the Adapter as 12 V DC @ 9.6 Amps and 5V DC @ 1Amp.  If I calculate P=VI, total power is coming to 120 Watts at DC.  Will DC wattage is equal to wattage at AC?  What wattage of converter I need to buy to hook up this adapter?

Thanks in Advance

Thank you dc42.  After doing some research on internet, I too realized that snubber circuits may not be useful in suppressing the arc totally.  So I am left out with the option building my own SSR.  Good news is there a snubberless version available in BTA16 Triac series for inductive loads.

Thank you!..  I got my question answered.

OK thanks.  I understand I need to keep the reset pin to high using a pull up resister.  So the question is, power recycling the board is not going to reset?  Power recycling is not just like reset? Just curious to know. 

On standalone projects, is reset switch necessary? Is there any difference between power recycle and reset?

Thanks all for your responses.  I have decided to go with 10 Amps relay.  For the snubber network, If have one capacitor of 10nf/680V and one resistor 39R in series across the relay switching terminals, is that sufficient?

Hi There!

I want to control (on and off) 1.5 HP, 220VAC motor from Arduino.  I am thinking of controlling the motor by building a solid state relay using MOC 3021 and triac BTA16.  Is this the best approach? or using a relay is the simple and better option?  Need to know any advantages and disadvantages of both the approaches.  Any suggestions are welcome.  Thanks in advance.

Thank you!

@Krodal

Yes,  The pressure sensor is underneath the black rubber and there are three pins to connect.  Its similar to DN-S18 in the link you mentioned

Hi There!

I am looking for a pressure sensor to measure the continuous water level in a tank.  The area where I live it’s difficult to get the pressure sensors.  Fortunately I could spot a guy who sells the washing machine spares.  He has a sensor(picture attached) but he has no clue how it should be fixed, neither me.  My understanding is,  it will output 0 to 5V based on the pressure, I can connect the output to arduino analog pin and measure the water level in the tank.  But the question is,  usually how its fixed in the washing machines? Will water goes in the tube attached to this sensor, or some other mechanism like air bag used to measures the air pressure?  Any or all suggestions are welcome.  Thanks in Advance.