Arduino programming HELP NEEDED!!!

Can you please post your currant code and circuit diagram. Also, if it is literally just switching something on at a certain time, you may be better off with one of these:

http://www.amazon.co.uk/Electronic-digital-mains-Socket-Display/dp/B002P7RF9A/ref=sr_1_1?ie=UTF8&qid=1408837264&sr=8-1&keywords=plug+timer

I use and old mechanical version to automatically switch off my soldering iron every 20 minutes so I cant leave it on overnight.

I don't really have any code yet. Everything I have started on is a bust. I am building a school bell timer to ring before and in-between classes. I have an arduino uno, a sainsmart 2-channel relay module, and a tinyrtc ic2. Currently the bell is operated by a button wich closes the connection between two wires. All I need to do is tell the arduino to switch the relay and close the connection for 'x' amount of time (about 2 seconds) at certain times throughout the day.

Change rtc to RTC (block capitals)
and delete the curly brace directly underneath it. It is quite late where I am at the moment so I am making a few silly mistakes.

I got the time set, but when I upload the bellring sketch I get this

BellRing.ino:19:7: error: use of undeclared identifier 'now'

  if (now.hour() == 21 && now.minute() == 26){

  ^
BellRing.ino:19:27: error: use of undeclared identifier 'now'

  if (now.hour() == 21 && now.minute() == 26){

  ^
2 errors generated.

Add this line directly above the first bellring module. (line 17): DateTime now = RTC.now();

Okay. That worked. Also I forgot to mention that my relay module works different than most others. It switches OFF when power is supplied to the control pin. To fix that I would just have to switch the 'HIGH' and 'LOW' in your code, correct?

Yep, that is correct. I also recommend that you add the line "digitalWrite(relay,HIGH);"  between line 14 and 15. Without this the bell will ring non stop until the first alarm as the pin defaults as low. An active low relay seems quite dangerous to me. Here, if the control circuitry fails the bell will ring constantly, and in an oven this could start a fire. I recommend you add a suitable switch to override the relay to spare everyone's ears if it does go wrong.

I just tested it out but it was delayed by about a minute and the relay stayed on for almost two minutes

how long did you set the relay to go on for what number did you actually enter. As for the delay, your time may be a minute or so behind from when you where uploading the time. It probably took about a minute for the rtc to be programed with the time from when you entered it in the time setting program. Try setting the time a minute in the future when using the upload program to help compensate.

I set the belltiime as "2" and then changed the "(belltime*1000)" to just "(2000)" but it still does the same thing

my bad. I forgot to add the (delay59000) after the last relay command.

Try running the blink sketch with the relay connected to pin 13. If that works then I don't know what the problem is. If it fails, then I think the problem is your relay. Test and report back.

Try running the blink sketch with the relay connected to pin 13. If that works then I don't know what the problem is. If it fails, then I think the problem is your relay. Test and report back.

I got your sketch to work okay. the only problem im having is setting and keeping the time on the RTC module. If i set the time with a sketch that outputs to a serial monitor, the time resets back to what it was originally set to everytime the serial monitor is opened. The only way i can get the time to set is by not outputting to a serial monitor, but then i cant see whats going on and im blinded.

But it is working, right? Do you have a battery installed in the RTC. If not, install one. Other than that I don't know what the problem is.

there is a network plug right beside where this will be located. Would it be better to have it get the time from the internet? but then again if the internet goes down the bell wouldnt work.

Probably not, this would be way to complex. I am still unsure, is it working? If so, why do you need a serial monitor?

yes, your code works. but i just tried to check/change the time on the rtc and it quit working. The only reason i need the serial monitor is to check and see what the time on the rtc is.

This code should do the job. You can set a time in the main block where you would normally set the bell to go off and it will turn on the boards built in led at this time. Not as good as serial but an acceptable workaround. I need to sign off now so I won't be able to provide further help until tomorrow.

//Bellclock v1.0 Created by kidiccurus I alow you to use this program on the condition that no more than 1 (one) Great British Pound (GB£) of revenue will be generated as a result of its use or sale. Just put that in there to stop you selling this to anyone
//Conect your relay to digital pin 4
//requires the libary you just installed
 
#include <Wire.h>
#include "RTClib.h"
int relay = 13;
RTC_DS1307 RTC;
void setup() {
  Wire.begin();
   RTC.begin();
   pinMode(relay,OUTPUT);
}
void loop() {
  
 //This module rings the bell. In the top row, the number 12 can be changed for the hour in 24 hour format and the number 0 can be changed for the minute (0-59).
 //Please copy and paste this module as many times as required 
  if (now.hour() == 12 && now.minute() == 0){
    digitalWrite(relay,HIGH);
    delay(belltime*1000);
  };
 //This is the end of the module if you are going to copy and paste
  
}

I dont believe there is anything different about this code??

I removed the part to switch off the pin after 2 seconds and changed it to activating pin 13 and the internal LED  for easy checking. Otherwise, yes it is the same.

This is the code I have used to correctly set and keep the time on the RTC module. Everything else I have used makes the RTC's time reset if the serial monitor is opened. However the time still resets on loss of arduino power, as if the coin cell battery is not installed. If you look at the code attached, I also have it monitoring the battery voltage, so I know that the battery is correctly installed and charged. I just don't know why it is not working correctly. Maybe I just don't know what im doing, but I have ordered another RTC and it will be delivered tonight. I'm hoping my first one is just faulty. The only thing different I have noticed about THIS code is the library included at the beginning. "RTC_DS1307" as opposed to the others, "rtc_millis".

//Arduino with Tiny RTC I2C http://zygzax.com/?lang=en

#include <Wire.h>

#include "RTClib.h"

RTC_DS1307 RTC;

void setup () {

  //Initialize the serial port, wire library and RTC module

    Serial.begin(9600);

    Wire.begin();

    RTC.begin();

    //If we remove the comment from the following line, we will set up the module time and date with the computer one

    //RTC.adjust(DateTime(__DATE__, __TIME__));

}

void loop () {

  int sensorValue = analogRead(A0);

  float voltage = sensorValue * (5.0 / 1023.0);

  Serial.println(voltage);

    DateTime now = RTC.now();

    //We print the day

    Serial.print(now.day(), DEC);

    Serial.print('/');

    //We print the month

    Serial.print(now.month(), DEC);

    Serial.print('/');

    //We print the year

    Serial.print(now.year(), DEC);

    Serial.print(' ');

    //We print the hour

    Serial.print(now.hour(), DEC);

    Serial.print(':');

    //We print the minutes

    Serial.print(now.minute(), DEC);

    Serial.print(':');

    //We print the seconds

    Serial.print(now.second(), DEC);

    Serial.println();

    //We check the time and sent through the serial port every 3s

    delay(1000);

}

I recommend that you just set the time with a bit of trial and error.