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All decoupling capacitors should be placed as close to the component as possible and the wires to it should be as short as possible.

A capacitor either side of the diode helps make it a better circuit. Diodes generate noise and the cap helps to suppress it.
There is a chance that the 328P gives a Vol (at full load) that is in this 'forbidden' region. Now life is not that bad if you limit the current to a few mA; see fig 31-306 on page 479 of the 328P datasheet that shows that at lower sink currents the Vol is close to 0V.
I am just presenting below a diagrammatic representation of your above proposition:

Input currents of the TTL gate are very low (20 uA/1.3 mA) compared to UNO (20mA/20mA) that the UNO could be considered as being operated at a very low load condition; as result, the output of the UNO will always remain much below of the forbidden zone.

BTW:By linear calculation -- the UNO will  be able to drive (fan-out) directly about 10 TTL gates safely (((20/1.3)/0.9)*0.8 = 13 ---> 10).
Oh well ,actually i am able to create the number of pulses according to user input but I cant figure out how to incluse time period also according to without conflicting the readkaypad();//(function used to read keyapad )which I used for user input pulses

while(key!='A')//I have given character A for generating pulses

      for (int k = 0; k <pos; k++)
        digitalWrite(ledind,HIGH) ;
        digitalWrite(pulsepin, LOW);   // sets the pulse on
        delay(20);                  // waits
        digitalWrite(pulsepin, HIGH);    // sets the pulse off
        delay(20);    // waits
I want to make the 20 inside the delay to be also user input
Programming Questions / Re: how to create functions th...
Last post by pert - Today at 06:29 am
This one seemed pretty good to me:
Nice job, however you are using Breadboards, when you need them, I thought you not using them at all.
What makes you say that? There are no bread boards on any of those pages.
Can you tell me your experience on C/C++ and/or any other languages that you fell comfortable with?
with the HC version, one is always safe.
So it's probably safe to use a 74HCT4051, but a 74HC4051 is guaranteed to work with the 328P in all possible conditions.
You are right and thank+ you for pointing out my mistake!
So this is a pretty newbie question and im pretty sure it has something to do with classes. I am looking for a way to create functions with the variable being set before the function

examples of these are:

i tried reading a book on basics of functions and classes however i found it completly useless and glossed over classes.
Software / Re: Data log tempo di accensio...
Last post by PaoloF_60 - Today at 05:59 am
invece bisogna trovare una maniera di salvare a comando i dati nel file sulla scheda sd

Code: [Select]

String Command="";

void setup() {
  // put your setup code here, to run once:

void loop() {
  // put your main code here, to run repeatedly:
  if (Serial.available() > 0) {
    String Command=Serial.readStringUntil('\n');
    if (Command="save") {
      Serial.println("Salvo File");

una seriale รจ sempre disponibile

I have transfered the sketch WebClient from one of the examples, configured the MAC address given by the sticker on the ethernet port built-in to the Intel Galileo generation 2 board. I simply want to know if my connection was succesful to the internet. This is the first time I'm using the serial monitor to debug a live sketch so I may have missed a step in setting it up for debugging. The lights on the ethernet ports light up so I think it's connected properly. I also have my Board and COM port set ot their right values. The text message is attatched and as you can tell it's not in English and finally here is the full code so you may see the changes I made to the example:

Code: [Select]
  Web client

 This sketch connects to a website (
 using an Arduino Wiznet Ethernet shield.

 * Ethernet shield attached to pins 10, 11, 12, 13

 created 18 Dec 2009
 by David A. Mellis
 modified 9 Apr 2012
 by Tom Igoe, based on work by Adrian McEwen


#include <SPI.h>
#include <Ethernet.h>

// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = { <censored> };
// if you don't want to use DNS (and reduce your sketch size)
// use the numeric IP instead of the name for the server:
//IPAddress server(74,125,232,128);  // numeric IP for Google (no DNS)
char server[] = "";    // name address for Google (using DNS)

// Set the static IP address to use if the DHCP fails to assign
IPAddress ip(192, 168, 0, 177);

// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 80 is default for HTTP):
EthernetClient client;

void setup() {
    system("ifup eth0");
  // Open serial communications and wait for port to open:
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only

  // start the Ethernet connection:
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    // try to congifure using IP address instead of DHCP:
    Ethernet.begin(mac, ip);
  // give the Ethernet shield a second to initialize:

  // if you get a connection, report back via serial:
  if (client.connect(server, 80)) {
    // Make a HTTP request:
    client.println("GET /search?q=arduino HTTP/1.1");
    client.println("Connection: close");
  } else {
    // if you didn't get a connection to the server:
    Serial.println("connection failed");

void loop() {
  // if there are incoming bytes available
  // from the server, read them and print them:
  if (client.available()) {
    char c =;

  // if the server's disconnected, stop the client:
  if (!client.connected()) {

    // do nothing forevermore:
    while (true);
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