It/Hardware/Arduino Bell System
New Code
Developed by Walter DeMoss
Old Code
Developed by Micah Henney
Source code for the arduino bell system using the DS3231 RTC module and doorbells.
/**
* An arduino program to ring the doorbells at MSG on the bell schedule.
* Written by Micah Henney. Last updated February 2, 2024.
*
* Made for use with DS3231 RTC module. A similar program exists for the DS1302/DS1307
* but that module keeps less accurate time due to an external temperature crystal.
*
* The RTC module should be connected through I2C using the default arduino I2C pins SDA and SCL.
* Run Vcc on 5V and GND on GND. Do not connect SQW and 32K.
* To connect the bell system transmitter, take apart one of the doorbell buttons and solder pins
* to the positve and negative battery terminals, as well as the top left pin of the button.
* Connect the postive battery terminal to Vin (works on 5V, but made for 12V so Vin allows it to
* receive more power if available), the negative terminal to GND, and the button lead to pin 8
* (defined below PIN_TRIG). The arduino will pull the button lead LOW to trigger the transmitter.
*
* To set the schedule times, change the below lines mondayRingtimes and ringtimes. They are split
* because VTE has a different schedule on Monday. CNX has the same ringtimes every day, so each
* has the same values. Format is timeInDay(HourAs24, Minute, Second)
*
* To change the schedule ring times, the code must be reuploaded. Setting the current time can be
* done through Serial. To change the schedule, change the times below, plug in the arduino and
* upload the code. Then set the current time. To set the current time, plug in the arduino and
* connect to the serial monitor. The board will print out the current set time, then how long it
* will wait before ringing. If it is correct, no additional steps are required. If not, type the
* current time in the serial monitor input in the format YYMMDDwHHMMSSx (the x at the end is
* required, and all numbers except day of week must be 2 digit. Day of week Monday = 1) For
* example, if the current time is Thursday, February 15 2024 at 2:17:00 PM, type "2402154141700x"
* and enter (meaning year 2024, month 02, day 15, day of week 4, hour 14, minute 17, second 00)
* Reset the board and confirm that it now shows the correct time.
*
* To pair the button transmitter with the alarm component of the doorbell, press the tone selector
* on the doorbell until the desired tone plays. Hold the volume button for 4 seconds until the blue
* light turns solidly on, then press the transmitter. The doorbell light will blink and turn off.
* Pairing is successful.
*
* When not connected to serial, the arduino onboard LED will blink once for every 10 minutes
* remaining until the next ringtime, up to a maximum of 20 blinks. It will sleep for about 8
* seconds between each blink sequence.
*/
#include <DS3231-RTC.h>
#include <Adafruit_SleepyDog.h>
RTClib Rtc;
DS3231 ll_rtc;
#define countof(a) (sizeof(a) / sizeof(a[0]))
#define timeInDay(h, m, s) ((unsigned long)(h) * 60 * 60 + (m) * 60 + (s))
#define PIN_TRIG 8
unsigned long mondayRingtimes[] = {timeInDay(7, 45, 30), timeInDay(8, 0, 0), timeInDay(9, 10, 0), timeInDay(9, 15, 0), timeInDay(10, 23, 0), timeInDay(10, 55, 0), timeInDay(11, 0, 0), timeInDay(12, 10, 0), timeInDay(12, 55, 0), timeInDay(14, 0, 0), timeInDay(14, 30, 0), timeInDay(14, 35, 0), timeInDay(15, 40, 0), timeInDay(15, 55, 0), timeInDay(17, 0, 0)};
// {timeInDay(7, 15, 0), timeInDay(9, 50, 0), timeInDay(9, 55, 0), timeInDay(11, 10, 0), timeInDay(11, 45, 0), timeInDay(13, 0, 0), timeInDay(13, 5, 0), timeInDay(13, 35, 0), timeInDay(13, 40, 0), timeInDay(15, 35, 0)};
unsigned long ringtimes[] = {timeInDay(8, 0, 0), timeInDay(9, 10, 0), timeInDay(9, 15, 0), timeInDay(10, 23, 0), timeInDay(10, 55, 0), timeInDay(11, 0, 0), timeInDay(12, 10, 0), timeInDay(12, 55, 0), timeInDay(14, 0, 0), timeInDay(14, 30, 0), timeInDay(14, 35, 0), timeInDay(15, 40, 0), timeInDay(15, 55, 0), timeInDay(17, 0, 0)};
// {timeInDay(7, 15, 0), timeInDay(9, 50, 0), timeInDay(9, 55, 0), timeInDay(11, 10, 0), timeInDay(11, 45, 0), timeInDay(13, 0, 0), timeInDay(13, 5, 0), timeInDay(13, 35, 0), timeInDay(13, 40, 0), timeInDay(16, 25, 0)};
DateTime next;
bool timeJustSet = false;
void setup()
{
pinMode(PIN_TRIG, OUTPUT);
digitalWrite(PIN_TRIG, HIGH);
delay(100);
Serial.begin(9600);
Wire.begin();
delay(500);
DateTime now = Rtc.now();
DateTime test = DateTime(now.getUnixTime());
Serial.print("Current time: ");
printDateTime(now);
Serial.println();
delay(500);
getNext(now);
}
void getNext(DateTime now)
{
unsigned long cmp = timeInDay(now.getHour(), now.getMinute(), now.getSecond());
if (now.getWeekDay() == 1) // Monday
{
Serial.println("Monday");
if (cmp > mondayRingtimes[countof(mondayRingtimes) - 1])
{
// It's Monday night. Next ringtime is Tuesday morning
next = timeOnDay(now, 2, ringtimes[0]);
return;
}
else
{
// Use the next Monday ringtime
for (int i = 0; i < countof(mondayRingtimes); i++)
{
if (cmp < mondayRingtimes[i])
{
next = timeOnDay(now, 1, mondayRingtimes[i]);
return;
}
}
Serial.println("This should never happen x1");
}
}
else
{
if (now.getWeekDay() == 5) // Friday
{
Serial.println("Friday");
if (cmp > ringtimes[countof(ringtimes) - 1])
{
next = timeOnDay(now, 1, mondayRingtimes[0]);
return;
}
else
{
for (int i = 0; i < countof(ringtimes); i++)
{
if (cmp < ringtimes[i])
{
next = timeOnDay(now, 5, ringtimes[i]);
return;
}
}
Serial.println("This should never happen x2");
}
}
else
{
// It's a Tuesday through Thursday. We can add one day and do tomorrow if not sometime today
if (cmp > ringtimes[countof(ringtimes) - 1])
{
// Ring tomorrow morning
next = timeOnDay(now, now.getWeekDay() + 1, ringtimes[0]);
return;
}
else
{
// Get next ringtime today
for (int i = 0; i < countof(ringtimes); i++)
{
if (cmp < ringtimes[i])
{
next = timeOnDay(now, now.getWeekDay(), ringtimes[i]);
return;
}
}
Serial.println("This should never happen x3");
}
}
}
}
DateTime timeOnDay(DateTime reference, uint8_t dow, unsigned long time)
{
if (reference.getWeekDay() == dow)
{
return DateTime(reference.getYear(), reference.getMonth(), reference.getDay(), time / 60 / 60, (time % 3600) / 60, time % 60, dow);
}
else
{
// Number of days until dow
long addDays = (dow + 7 - reference.getWeekDay()) % 7;
long diff = (addDays * 60 * 60 * 24);
// Subtract seconds between 1970 and 2000
// For some reason constructor assumes from Y2K
DateTime sometimeInDay = DateTime(diff + reference.getY2kTime());
DateTime ret = DateTime(sometimeInDay.getYear(), sometimeInDay.getMonth(), sometimeInDay.getDay(), time / 60 / 60, (time % 360) / 60, time % 60, dow);
return ret;
}
}
void printDateTime(DateTime dt)
{
char datestring[50];
dt.show_DateTime(datestring, sizeof(datestring));
Serial.print(datestring);
}
void loop()
{
DateTime now = Rtc.now();
if(timeJustSet) {
getNext(now);
timeJustSet = false;
delay(1000);
return;
}
setTime();
long timeToWait = next.getUnixTime() - now.getUnixTime();
if (timeToWait < 0)
{
Serial.println("Ring");
// Blink the on board LED as well
digitalWrite(13, HIGH);
digitalWrite(PIN_TRIG, LOW);
delay(2000);
digitalWrite(13, LOW);
digitalWrite(PIN_TRIG, HIGH);
getNext(now);
Serial.print("Next ringtime: ");
printDateTime(next);
Serial.println();
}
else if (timeToWait < 10)
{
delay(50); // Delay for 1/20th of a second
}
else
{
// Blink onboard led once per 10 minutes remaining
long minutesToWait = timeToWait / 60;
Serial.print("Minutes to wait: ");
Serial.print(minutesToWait);
Serial.println();
if (!Serial)
{
for (int i = 0; i < min((minutesToWait / 10) + 1, 20); i++)
{
digitalWrite(13, HIGH);
delay(200);
digitalWrite(13, LOW);
delay(200);
}
Watchdog.sleep();
}
else
{
delay(2000);
}
}
}
void parseSetTimeInput(byte &year, byte &month, byte &date, byte &dOW,
byte &hour, byte &minute, byte &second)
{
// Call this if you notice something coming in on
// the serial port. The stuff coming in should be in
// the order YYMMDDwHHMMSS, with an 'x' at the end.
boolean gotString = false;
char inChar;
byte temp1, temp2;
char inString[20];
byte j = 0;
while (!gotString)
{
if (Serial.available())
{
inChar = Serial.read();
inString[j] = inChar;
j += 1;
if (inChar == 'x')
{
gotString = true;
}
}
else
return;
}
Serial.println(inString);
// Read year first
temp1 = (byte)inString[0] - 48;
temp2 = (byte)inString[1] - 48;
year = temp1 * 10 + temp2;
// now month
temp1 = (byte)inString[2] - 48;
temp2 = (byte)inString[3] - 48;
month = temp1 * 10 + temp2;
// now date
temp1 = (byte)inString[4] - 48;
temp2 = (byte)inString[5] - 48;
date = temp1 * 10 + temp2;
// now Day of Week
dOW = (byte)inString[6] - 48;
// now hour
temp1 = (byte)inString[7] - 48;
temp2 = (byte)inString[8] - 48;
hour = temp1 * 10 + temp2;
// now minute
temp1 = (byte)inString[9] - 48;
temp2 = (byte)inString[10] - 48;
minute = temp1 * 10 + temp2;
// now second
temp1 = (byte)inString[11] - 48;
temp2 = (byte)inString[12] - 48;
second = temp1 * 10 + temp2;
}
void setTime()
{
if (!Serial)
return;
if (Serial.available())
{
byte year;
byte month;
byte date;
byte dOW;
byte hour;
byte minute;
byte second;
parseSetTimeInput(year, month, date, dOW, hour, minute, second);
ll_rtc.setClockMode(false); // set to 24h
// setClockMode(true); // set to 12h
ll_rtc.setYear(year);
ll_rtc.setMonth(month);
ll_rtc.setDate(date);
ll_rtc.setDoW(dOW);
ll_rtc.setHour(hour);
ll_rtc.setMinute(minute);
ll_rtc.setSecond(second);
timeJustSet = true;
}
}