An application to read a twitter timeline.
With support for Serial and 20x4 lcd output.
I tested it on an ATMega2560.
Individual tweets can contain very long embedded links.
This makes the tweet text limit of ~140 characters a bit of a farce.
So using an Arduino with less memory than the mega would be a challenge.
I have recently updated the software adding #tag and @someone support. (See attachment)
There is limited support for common french accented characters.
The lcd display section tries not to break up words across lines.
I have experienced occasional missing characters in the input section. If these remove part of a "<a href=" reference it can occasionally mess up the tweet parsing.
Constructive suggestions invited.
David
Part one of App:
// YiFi101tweetRead2.ino
// Read Twitter timeline
// tested on ATmega2560
// Will not work on protected accounts (Nor should it!)
// Serial support
// LCD Support (20 x 4)
// I used an in-expensive 20x4 LCD "4-Line Module":
// with Blue Backlight and I2C Interface
// from http://www.4tronix.co.uk/store/
// Item #: ARD20X4I2C
// connected to 0V, 5V, SDA and SCL on the Mega
// lcd backlight toggled with WiFi button
// Select the number of recent tweets to read
// Display tweets on lcd:
// requires suppression of tweet links
// Option to suppress images and linked URL's using boolean nolink
// tweet recovery limited to a line length of 998 (+ "\n") characters per tweet
// (unless maxtweets = 0)
// if maxtweets = 0, all of the response is printed and not processed
// Some sites have tweets with embedded links that are incredibly long!
// A tweet should have no more than 140 text characters (ho Ho)
// Reloading un-changing tweets can be prevented with bailout = true
// Led with series 1Kohm resistor between pin 12 and ground- active during reading
// Switch between pins 8 and 9 to toggle lcd scrolling
// D.R.Patterson
// 24/12/2016
#include <SPI.h>
#include <WiFi101.h>
#include <LiquidCrystal_I2C.h>
// set the LCD address to 0x27 for a 20 chars 4 line display
// Set the pins on the I2C chip used for LCD connections:
// addr, en,rw,rs,d4,d5,d6,d7,bl,blpol
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
#include <Wire.h>
// custom pound using https://omerk.github.io/lcdchargen/
byte customPound[8] = {
0b01100,
0b10010,
0b01000,
0b11100,
0b01000,
0b01000,
0b11110,
0b00000
};
const byte wifiSelect = 10; // YiFi101 select (active low)
int mystatus = WL_IDLE_STATUS;
const byte button = 6; // attached to on-board button
const byte smonitor = 8; // if low no led scrolling
const byte pinlow = 9; // convenient low pin next to monitored pin
const byte led = 12; // led pin
boolean lcdlight = true;
// ######### Modify this section ########################################
#define LIB_DOMAIN "mobile.twitter.com"
const String twittername = "bbcnews"; // cnn, bbc etc
const byte sdSelect = 53; // SD select (active low)
const char ssid[] = "xxxx"; // your network SSID (name)
// add password support/keyIndex if required
// and amend line with mystatus = WiFi.begin(ssid);
const unsigned int maxtweets = 10; // 0 get all the available html without selection
// 1 get last tweet, 10 get last 10 tweets etc
// 10 works well without adjustment in main loop timing
const unsigned long reloadTime = 900000; // time between re-loads 15 minutes
// (at least maxtweets *70000) + 20% if scrolling is used
const unsigned long chardelay = 240; // delay for visible character display during lcd scroll
const unsigned long waitTime = 10000; // wait for wifi101 to settle (mS)
const boolean nolink = true; // filter links and allow lcd to show tweet
// if false, will serial print (if debug true)
const boolean debug = true; // extended serial output
const boolean bailout = false; // if true, when identically ordered tweet id's are found,
// data processing ceases for a quick exit.
// if false, reloads the tweets again
boolean scroll = true; // Scroll tweets on lcd- will be over ruled if using monitored switch
const boolean haveSwitch = true; // set to true if using a switch beteen pin 9 and 8 to
// control lcd scrolling
const unsigned int maxSlength = 998; // maximum length of a processed string. 998 for mega
const char pound = 1; // custom char "£" (closest £ on my lcd was 193 and it was poor)
// ######## End of modify ###############################################
int lastTweet = -1;
String content[maxtweets]; // tweet storage
const String clearit = " ";
unsigned long tstart;
void setup(){
// setup wifi and sd select
pinMode(sdSelect, OUTPUT); digitalWrite(sdSelect, HIGH);
pinMode(wifiSelect, OUTPUT); digitalWrite(wifiSelect, LOW);
pinMode(button, INPUT_PULLUP);
// setup monitored pin
pinMode(pinlow, OUTPUT); digitalWrite(pinlow, LOW);
pinMode(smonitor, INPUT_PULLUP);
// led pin
pinMode(led, OUTPUT); digitalWrite(led, LOW);
Serial.begin(115200);
while(!Serial) yield();
lcd.begin(20,4);
delay(250);
lcd.clear();
// create a new custom character
lcd.createChar(1, customPound);
lcd.clear();
lcd.backlight();
lcd.print(F("Twitter Timeline"));
wifiConnect();
// wait for wifi to settle
lcd.setCursor(0,2); Serial.print(F("Settling Wifi"));
lcd.print(F("Settling Wifi"));
delay(waitTime);
lcd.setCursor(0,2); lcd.print(clearit);
String retval = readtwitter(maxtweets);
if (debug && retval != "0") Serial.println("Connection returned " + retval);
tstart = millis();
}
void loop(){
static int dcount = 0;
String message, temp;
int E;
if(haveSwitch) scroll = digitalRead(smonitor); // use switch to set scroll
// comment out if not using switch
checkbutton(); // look for wifi button press
unsigned long tnow = millis();
if ( (tnow - tstart) > reloadTime) { // default = 15 minutes
// keep rate down to make twitter happy
// timing optimized for 10 tweets
mystatus = WiFi.status();
if (mystatus != WL_CONNECTED) { // lost the wifi
lcd.clear(); lcd.print(F("WiFi Signal lost"));
wifiConnect(); // re-connect
tnow = millis();
}
String retval = readtwitter(maxtweets);
if (retval != "0" && debug) Serial.println("Connection returned " + retval);
tstart = tnow;
dcount = 0; // reset tweet display count for lcd
}
if(nolink){ // put the tweet on the lcd
if (lastTweet >= 0){ // require at least 1 tweet (1st tweet = 0)
message = content[dcount];
message = String(dcount + 1) +": " + message;
Serial.print("\n" + message);
// line above line display
message.replace("\n\n","\n"); // remove any repeated \n to improve lcd layout
message.replace(char(163),char(pound)); // swap £ for a custom char on the lcd
while (message.length()) {
lcd.clear();
for(int i = 0; i < 4; i++){ // split message up to display on a 4 line 10x4 lcd
int S = 0;
E = message.indexOf("\n");
if (E > 20) {
E = 20;
temp = message.substring(0, E );
// remove leading spaces
int L = 0;
while(byte(temp.charAt(L) ) == 32) L++;
if (L > 0) temp.remove(0, L);
// avoid spliiting words
char N = message.charAt(E);
if (!(N== 0 || N==10 || N==13 || N == 32 )){
int B = temp.lastIndexOf(" ");
if (B>-1){
E = B;
temp = temp.substring(0, E );
S = 1;
}
}
// end of avoid splitting
}else{
S = 1;
temp = message.substring(0, E );
}
temp.trim();
message.remove(0, E+ S);
lcd.setCursor(0, i);
lcd.print(temp);
if (message.length() == 0) break;
}
if (message == "\n") message = ""; // no point in starting a new panel
mydelay(5000);
}
if(scroll){
// scroll the mesage on line 2 of the lcd
lcd.clear();
lcd.print( twittername + ", " + String(dcount + 1));
message = content[dcount];
message.replace(char(163),char(pound)); // swap £ for a custom char
lcdscroll(message, 2, false ); // params: (message, line number, clear the line first
}
dcount++; // tweet counter
if(dcount > lastTweet) dcount = 0;
}
}
}
YiFi101tweetReadForum.zip (6.9 KB)
