void loop() {  
    if (millis() > bot_last_check + bot_check_interval) {  
    int numNewMessages = bot.getUpdates(bot.last_message_received + 1);  
    while (numNewMessages) {  
    for (int i = 0; i < numNewMessages; i++) {  
    String chat_id = bot.messages[i].chat_id;  
    String msg = bot.messages[i].text;  
    Serial.println("Chat id:" + chat_id);  
    Serial.println("Msg: " + msg);  
    if (chat_id != "your_chat_id") {  
    bot.sendMessage(chat_id, "You are not authorize to use this bot", "");  
    continue;  
    }  
    if (msg == "/capture") {  
    sendImage(chat_id);  }  
    }  
    numNewMessages = bot.getUpdates(bot.last_message_received + 1);  
    }   
    bot_last_check = millis();  
    }   
    // delay(10); 
    }