Let me preface this post by stating that I have very little experience with programming.
I very recently started using the Arduino microcontroller and I've completed Lady Ada's lessons 0-5 along with the easier tutorials on the Arduino.cc site with relatively few hiccups. My next task is to come up with a prototype with an output we haven't had experience using in my class -- I've chosen to use Twitter as that output.
I've been able to post a tweet to the account with a simple button press, but I need to increase the difficulty by adding if/else statements to tweet various phrases depending on which button I press. It didn't seem too hard but I've encountered problems. I've searched through these forums with the purpose of "borrowing" code to suit my needs. I've come across another thread entitled "twitter sketch posts only once" and it had what I needed. I did try using that code but I am now unable to tweet anything. Will anyone help a newbie out?
Thanks for your time,
Ouchb.
// LIBRARIES
#include <SPI.h>
#include <Ethernet.h>
#include <Udp.h>
#include <EthernetDNS.h>
#include <Twitter.h>
#include <Client.h>
#include <Server.h>
// USA
const int buttonPinUSA = 0; // USA BUTTON/SWITCH
const int buttonLedUSA = 1; // USA BUTTON/SWITCH LED
int buttonStateUSA = 0; // USA BUTTON/SWITCH STATE (HIGH OR LOW)
// SOVIET UNION
const int buttonPinSOVIETUNION = 2; // SOVIET UNION BUTTON/SWITCH
const int buttonLedSOVIETUNION = 3; // SOVIET UNION BUTTON/SWITCH LED
int buttonStateSOVIETUNION = 0; // SOVIET UNION BUTTON/SWITCH STATE (High OR LOW)
// RANDOM INTEGER TO INSERT INTO TWEETS TO ALLOW DUPLICATE TWEETS
int randomValue = 0;
// KEEP TRACK OF LAST ACTIVATE STATE
int lastActivateState = 0;
// ETHERNET INITIALIZATON
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192, 168, 1, 109 }; // ETHERNET SHIELD IP ADDRESS
byte gateway[] = { 192, 168, 1, 1 }; // NETWORK DEFAULT GATEWAY
byte subnet[] = { 255, 255, 255, 0 }; // NETWORK SUBNET MASK
// TWITTER INITIALIZATION
Twitter twitter("TWITTER TOKEN"); // TWITTER TOKEN FROM HTTP://ARDUINO-TWEET.APPSPOT.COM/
const char* msg ="/meh/"; // PLACEHOLDER MESSAGE OTHERWISE COMPILER WILL ERROR
void setup()
{
Ethernet.begin(mac, ip, gateway, subnet);
Serial.begin(9600);
pinMode(buttonPinUSA, INPUT);
pinMode(buttonLedUSA, OUTPUT);
pinMode(buttonPinSOVIETUNION, INPUT);
pinMode(buttonLedSOVIETUNION, OUTPUT);
Serial.println("I am connecting ...");
msg = "initializing";
Tweet();
delay(2000);
}
void loop()
{
buttonStateUSA = digitalRead(buttonPinUSA); // READ USA BUTTON/SWITCH STATE
buttonStateSOVIETUNION = digitalRead(buttonPinSOVIETUNION); // READ SOVIET UNION BUTTON/SWITCH STATE
// CONDITION #1: THE USA BUTTON/SWITCH HAS BEEN ACTIVATED
if (buttonStateUSA == HIGH)
{
if (lastActivateState =! 1)
{
lastActivateState = 1;
digitalWrite(buttonLedUSA, HIGH);
msg = "Country: USA has been selected!";
Tweet();
Serial.println("USA Button/Switch has been activated");
}
}
// CONDITION #2: THE SOVIET UNION BUTTON/SWITCH HAS BEEN ACTIVATED
if (buttonStateSOVIETUNION == HIGH)
{
if (lastActivateState =! 2)
{
lastActivateState = 2;
digitalWrite(buttonLedSOVIETUNION, HIGH);
msg = "Country: SOVIET UNION has been selected!";
Tweet();
Serial.println("SOVIET UNION Button/Switch has been activated");
}
}
// DELAY WHILE TWITTER POSTS MESSAGES
delay(2000);
// ENDING VOID LOOP()
}
void Tweet()
{
char S[50];
randomValue = random(HEX);
/**********
* SprintF "stitches" together a string(msg) and a variable(randomVariable) into
* another string, "S".
**********/
sprintf(S, "SOMETHING %s(%i)tweets", msg, randomValue);
Serial.println(S);
Serial.println("connecting ...");
// TWITTER POST EXAMPLE REMAINING CODE
if (twitter.post(S))
{
int status = twitter.wait();
if (status == 200)
{
Serial.print("OK. code-");
Serial.println(status);
}
else
{
Serial.print("failed : code-");
Serial.println(status);
}
}
else
{
Serial.println("connection failed.");
}
}
Regarding pointers -- I've seen the '*' in different locations among threads about pointers. Both go through the compiler without error, so I guess they mean different things. What is that exactly?
char *msg;
char* msg;
I've removed the msg = "initializing";
I also have another question about the character buffer. Would it be okay if I put in a value that was greater than the amount of characters I would have in the tweet?
The position of the * is not important. Some people like char*, with the * next to the type. Others like char *, with the * next to the variable. I like the * next to the variable, to remind me that the variable IS a pointer.
The const in front of the pointer variable declaration means that you can't change where the variable points to. You can change the data that it points to, as long as the new data fits in the space being pointed to, but you can't make the pointer point somewhere else.
You can make S larger than it needs to be, with no ill effects. You can't make it smaller than it needs to be, though, and you can't change it's size once it is defined.
By the way, your sprintf statement won't do what you are hoping it will do, since you have no format specifiers for the variables you want converted to characters.
It is tweeting automatically and not upon a button press. It is trying to tweet condition #1 repeatedly (according to the serial monitor). The random number didn't appear at the end of the statement like I had hoped
I've switched the conditions around and it is still selecting the first condition automatically. I was in the process of switching out the buttons when I noticed that I was getting the serial print messages for the button presses (there wasn't anything attached to the board at the time -- aside from the ethernet cable and power source).
I was in the process of switching out the buttons when I noticed that I was getting the serial print messages for the button presses (there wasn't anything attached to the board at the time -- aside from the ethernet cable and power source).
Keep this up and you'll soon be posting over in Hardware + Troubleshooting forum asking for help on determining why your Arduino no longer works. Once little slip, and the Arduino is toast.
Anyway, digitalRead is meaningful only if there is something to read. I don't see any calls to digitalWrite() in setup(), so it appears that you are not using the internal pull-up resistors. This implies that you are using external pull-up or pull-down resistors. You are, aren't you?
Keep this up and you'll soon be posting over in Hardware + Troubleshooting forum asking for help on determining why your Arduino no longer works. Once little slip, and the Arduino is toast.
Geez. I did unplug it immediately after I saw that it was automatically running condition 1.
I am using external pull-down resistors (at least I think that's what my instructor said we were using). 100-ohm - 220-ohm resistors for the LEDs and 10k-ohm resistors for the switches.
Build a simple sketch to read each switch independently, and print to the Serial Monitor when the switch is pressed.
If both switches cause messages to appear in the Serial Monitor, then the switches are working, and the issue is with the code. If not, the problem is with the hardware.
[edit]Wait a minute. I just looked at your code again. You can't do this:
const int buttonPinUSA = 0; // USA BUTTON/SWITCH
const int buttonLedUSA = 1; // USA BUTTON/SWITCH LED
Pins 0 and 1 are the TX/RX (Serial) pins. You can't use them as switch pins at the same time you are using them for Serial communication.
[/edit]
