arduino real time clock ds3231 with lcd display for sale
Real time clock module with the DS3231 chip. This module ensures that the Arduino knows the exact time at all times. By connecting the Arduino to the ´qw´ pin, it is possible to generate an interrupt every second with which sensor values or a display can be addressed.
This module uses the DS3231, which is the big brother of DS1307. This chip has an integrated timing crystal and temperature sensor, which provides more stability. With this module you have just that little extra precision and reliability that the predecessor is missing. The chip is fully compatible with the predecessor and therefore requires no modification in the source code.
The DS3231 AT24C32 Real Time Clock Module adds timestamp and event scheduling information to your microcontroller projects. This module generates seconds, minutes, hours, day, date, month and year, and provides timekeeping until 2100 while compensating for leap years.
This device was added to Parallax inventory as a quick demonstration to the sample code for the Propeller 2 SPIN/PASM SPI Driver used in the Propeller 2 Live Forum and P2 Quick Byte “SPI Driver Object”. It is compatible with all Parallax microcontrollers, to provide simple visual feedback for numbers and data.
first time posting because I think I"ve bitten more than I can chew on my own. I have this project of a weather station using an Arduino UNO, a TFT LCD display, a DS3231 RTC module and a BME280 sensor. I have had the UNO and the DS3231 module for a while, unused from a pet feeder project that I didn"t finish. I bought the other components checking the compatibility with the UNO. I"ll probably add a button because I want the display to show everything on demand and I forgot to buy one.
I"ve found that the TFT LCD is an ILI9486 model and downloaded the library from 3.5inch Arduino Display-UNO - LCD wiki and I started with the display using the examples and wiring directions.
Then I"ve added the DS3231 RTC module. I"ve plugged it into the SDA and SCL pins because so many of the UNO pins are used by the LCD display and I"m using a library from DS3231 - Rinky-Dink Electronics, checking again with one simple program and one more complex that works fine. Everything is fine on the serial monitor.
But when I start integrating everything in one program, it"s not working anymore. The compilation doesn"t show any error. I"ve checked my code by excluding part of the functions and I"ve found that once I"m calling one of the rtc.getXXXXStr (XXXX being time, DOW or date) or even the rtc.getTime function adapted from a more complex example program, the LCD doesn"t display anything anymore, and every mylcd.xxx function gets ignored.
rtc module clock arduino rtc arduino clock clock real time arduino clock rtc ds1307 arduino clock rtc 3231 clock raspberry rtc ds3231 ds3231 rtc real time clock rtc raspberry nano shield real time clock arduino clock rtc rtc module rtc module rtc module rtc arduino adduino arduous raspberry afruit ino ds3231 raspberry clock arduino time arduino rtc module rtc module ds3231 module ds3231 module ds1307 time arduino rtc ds1307 arduino adafruit arduino i2c arduino real time modul horlog arduino horlog camera ds 3231 rtc modul ds. 3231 arduino arduino real time clock raspberry rtc arduino ds1307 azdelivery rtc clock rtc arduino arduino rtc ds3231 arduino time azdelivery real time clock ds 1307 clock ds3231 i2c clock real time clock module real time raspberry rtc ds 1307 rtc i2c module clock arduino ds1 307 module rtc ds1307 pi rtc rtc 1307 ds3231 at24c32 clock rtc raspberry module time arduino arduino rtc clock ds3231 and battery horlog arduino azdelivery arduino rtc module arduino ds1307 arduino arduino arduino clock module ds1307 rtc rtc clock DS3231 rtc module
All categories3D Printed Parts3D Printer partsAC-DC Boards & AdaptorsAcceleration & Rotation sensorAlphanumeric LCDAntennaArduino & AVRArduino & Interfacing CableAudio ConnectorsAudio ModulesBasic Robot PartsBatteryBattery HolderBergstripBiometric & Touch SensorBJTBLDC MotorBluetooth ModulesBMSBO MotorBox ConnectorBoxes & EnclosuresBreadboardBridge RectifierBuck-Boost ConvertersBuzzer and SpeakersCable ClampsCeramic CapacitorCOB LEDCommunication ModulesConsumablesControllers ICConverter ICCooling BlockCooling FanCrimping ToolsDC Gear MotorDC MotorDiacDigital Logic ICsDiodeDIP SwitchDot MatrixDrill ChuckDrone PartsEEPROM ICElectrolytic CapacitorEncoder & Decoder ICsEnd TerminalsESP BoardsFilm CapacitorFlat CablesForce & Pressure SensorsFuse & Fuse HoldersGeneral TransistorsGlue Gun and SticksGPS ModulesGraphics LCDGSM & GPRS ModulesHatchnHack KitsHatchnHack ProductsHealth SensorsHeat ShrinkHeat SinkHi-Link ConvertersHookup WiresICIC Base & Zif SocketsIGBT MOSFETIntegrated Circuits & ChipsIoT GatewaysJST FemaleJST MaleJST SM PairJumper WiresKoptan TapeLaser DiodeLEDLED DriversLED IndicatorLED StripsLight, Sound Sensor & Vibration SensorLimit SwitchMagnetic SensorsMeanwell SMPSMeasuring InstrumentsMicrophoneMiscellaneous Development BoardMiscellaneous ModuleModuleMolex ConnectorMornsun power SupplyMOSFETMOSFET/DIODEMotor AccessoriesMotor DriverMotor Driver ICMulti Strand WiresMultiturn PotentiometerN20 MOTORNeodymium MagnetsNuts & BoltsOperational amplifierOperational AmplifiersOptocoupler ICOptocouplersOrange PiOscillatorsOther Soldering ToolsOther ToolsPH SensorPot PotentiometerPotentiometerPotentiometer KnobsPower & Interface ConnectorsPower & Interfacing CablesPower AdapterPower Bank ModulePower mosfetPower transistorPower TransistorsPreset PotentiometerProgrammersPumps & ValvesPush ButtonsPVC Heat ShrinkPVC TerminalsPWM ICsRaspberry Pi & AccessoriesRectifierReed SwitchRegulatorRelay ModulesRelaysRelimate FemaleRelimate MaleremoteRemotesResistance Based Light SensorResistance Based SensorResistance Based Temperature SensorResistorResistor NetworkRF ModuleRocker SwitchRotary SwitchRTC & ADC ModulesServo MotorSeven Segment DisplaySlide & Toggle SwitchSMD Capacitors 0603SMD Capacitors 0805SMD Capacitors 1206SMD General DiodesSMD InductorSMD LEDSMD Resistor 0402SMD Resistor 0603SMD Resistor 0805SMD Resistor 1206SMD Schottky DiodesSMD Zener DiodesSmooth RodsSMPSSolar PanelsSoldering Iron & AccessoriesSpacers & StandoffStepper MotorSwitchSynchronous MotorTantalum CapacitorTapesTemp, Humidity & Gas SensorTerminal BlockThermal SwitchThrough Hole General DiodesThrough Hole InductorThrough Hole LEDThrough Hole Resistor 1/2WThrough Hole Resistor 1/4WThrough Hole Resistor 1/8WThrough Hole Resistor 10WThrough Hole Resistor 1WThrough Hole Resistor 2WThrough Hole Resistor 5WThrough Hole Schottky DiodesThyristorTimer ICsTouch ICTouch SwitchTransformersTransistorTriacsTrimpot PotentiometerTweezersUltrafast diodeUltrasonic & ProximityUltrasonic & Proximity SensorVaristorVibrator MotorVoltage & Current SensorVoltage regulatorVoltage RegulatorsVoltage_Sensor_Measuring_InstrumentsWater SensorWire Cutter & StrippersX Y PlottersZener DiodeZero Board & Copper CladsZip Ties
Recently I"ve been developing a new project that requires a sensor to be checked at a certain time of day. The unit will be battery powered, I didn"t want to be counting time continuously so I opted for a Real Time Clock (RTC) to trigger an interrupt pin at a specific time each day.
As with all Arduino projects there isn"t an automatic user interface and I wanted a way to set the clocks without having to set up a board and plug them into the laptop each time so I thought I"d get an LCD with a keypad and build a simple interface to set the RTCs up.
There was a learning curve:I had to learn about LCDsI had to learn about Keypads going to one analogue pinI discovered an issues with cheaper generic LCD Keypad shieldsI had to learn about manipulating bytes and, as it turned out, initiating them
The DS3231 has the ability to store:dates using two digit years,the current day of the week,time in hours, minutes & secondstime as 24 hour or 12 hour (with am and pm data)an alarm (alarm 1) that can be set from days to seconds and has five different methods of triggeringan alarm (alarm 2) that can be set from days to minutes and has three different methods of triggering
For my application I made a couple of decisions:I"m not bothered about 12 hour clocks so I was going to only use the clock in 24 hour mode.I only read dates in dd/mm/yy format so I wasn"t going to give the user an option to show dates in mm/dd/yy format. If that is your preference then the code is easy to adjust but you would have to pay attention to the sequencing during the date set up routine.
The first decision to be made was the sequencing of options for the user. The LCD has two lines of display so each step had to accommodate that. I didn"t want the LCD to scroll a new line up or down each time so I though it would be better if each screen presented had a theme.
When I first created the project I used the following sequences:Date & TimeAlarm 1Alarm 2Set DateSet TimeSet Alarm 1 On or OffSet Alarm 1 Date and/or timeSet Alarm 1 MethodSet Alarm 2 On or OffSet Alarm 2 Date and/or timeSet Alarm 2 Method
But this method took a lot of steps to get from simply displaying Alarm 1 back to Date & Time and also from displaying Alarm 2 to setting Alarm 2 so I changed the sequence:
I maintained the wiring for the LCD as if it had been plugged into an Arduino UNO so the code for initiating looks like:#include
I used the same variables for each of the buttons pressed. There is a lot of information on the internet about managing button bounce, I controlled it with a 50ms debounce delay. To learn more about debounce try this vide:
I also added a variable to store the last button pressed, this avoids the issue of long button presses. Because the Arduino loop runs very often every time it entered the loop after the debounce delay the code would act as if a new button had been pressed without this code.// check the key press against the previous key press to avoid issues from long key pressesif (oldKey!=lcd_key) {// depending on which button was pushed, we perform an actionswitch (lcd_key){case btnRIGHT:
Below is the initial code for the display sequencing, the first block is taken straight from the datasheet:/ define some values used by the panel and buttonsint lcd_key = 0;int adc_key_in = 0;const int btnRIGHT = 0;const int btnUP =1;const int btnDOWN =2;const int btnLEFT =3;const int btnSELECT =4;const int btnNONE =5;int bounceDelay;int oldKey = 0;/**************************************************************** Functions to read the buttons***************************************************************/// read the buttonsint read_LCD_buttons(){adc_key_in = analogRead(0); // read the value from the sensor// my buttons when read are centered at these valies: 0, 144, 329, 504, 741// we add approx 50 to those values and check to see if we are closeif (adc_key_in > 1000) return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result// For V1.1 us this thresholdif (adc_key_in < 50) return btnRIGHT;if (adc_key_in < 250) return btnUP;if (adc_key_in < 450) return btnDOWN;if (adc_key_in < 650) return btnLEFT;if (adc_key_in < 850) return btnSELECT;return btnNONE; // when all others fail, return this...}void loop() {//Set the menu item or display text for the usersetMenu();// read the buttonslcd_key = read_LCD_buttons();// check the key press against the previous key press to avoid issues from long key pressesif (oldKey!=lcd_key) {// depending on which button was pushed, we perform an actionswitch (lcd_key){case btnRIGHT:{oldKey = btnRIGHT;if (currentMode==modeSHOWDATETIME){currentMode=modeSHOWALARM1;}else if (currentMode==modeSHOWALARM1){currentMode=modeSHOWALARM2;}else if (currentMode==modeSHOWALARM2){currentMode=modeSHOWDATETIME;}delay(50);break;}case btnLEFT:{oldKey = btnLEFT;delay(50);break;}case btnUP:{oldKey = btnUP;delay(50);break;}case btnDOWN:{oldKey = btnDOWN;delay(50);break;}case btnSELECT:{oldKey = btnSELECT;if (currentMode==modeSHOWDATETIME){currentMode=modeSETDATE;}else if (currentMode==modeSHOWALARM1){currentMode=modeSETALARM1ON;}else if (currentMode==modeSHOWALARM2){currentMode=modeSETALARM2ON;}else if (currentMode==modeSETDATE){currentMode=modeSETTIME;}else if (currentMode==modeSETTIME){currentMode=modeSHOWDATETIME;}else if (currentMode==modeSETALARM1ON && Clock.checkAlarmEnabled(1)){currentMode=modeSETALARM1;}else if (currentMode==modeSETALARM1ON && !Clock.checkAlarmEnabled(1)){currentMode=modeSHOWALARM1;}else if (currentMode==modeSETALARM1){currentMode=modeSETALARM1METHOD;}else if (currentMode==modeSETALARM1METHOD){currentMode=modeSHOWALARM1;}else if (currentMode==modeSETALARM2ON && Clock.checkAlarmEnabled(2)){currentMode=modeSETALARM2;}else if (currentMode==modeSETALARM2ON && !Clock.checkAlarmEnabled(2)){currentMode=modeSHOWALARM2;}else if (currentMode==modeSETALARM2){currentMode=modeSETALARM2METHOD;}else if (currentMode==modeSETALARM2METHOD){currentMode=modeSHOWALARM2;};break;}case btnNONE:{oldKey=btnNONE;break;}}}}
When I entered the adjustment modes I need a way to show the user which part of the display they could adjust with the up or down arrows. I resolved this in four parts:an integer that changed as the user selected each different section of the display (with the left or right buttons)an integer to hold the maximum value for the blink integer, so that if the maximum number of blink stages (items on display) couldn"t be exceededa variable to hold the blink status (either true or false)a variable to hold the time in milliseconds since the blink status last changed, once that exceeded a set value the blink status changed from true to false or false to true as required.
Code added to the loop() function:void loop() {//Set the menu item or display text for the usersetMenu();// read the buttonslcd_key = read_LCD_buttons();// check the blink counter isn"t too highif (blinkInt > maxBlinkInt){blinkInt=maxBlinkInt;}// Set the current blink statusif (currentMode>modeSHOWALARM2 && ((millis()-blinkStart)>blinkDelay)){blinkNow=!blinkNow;blinkStart=millis();}else if (currentMode<=modeSHOWALARM2){blinkNow=false;}// check the key press against the previous key press to avoid issues from long key pressesif (oldKey!=lcd_key) {
This gave the following full setup and loop functions :void setup() {// Start the serial portSerial.begin(9600);Serial.println("Starting");// Set the bounce delaybounceDelay=50;// Start the lcd and set the cursorlcd.begin(16,2);lcd.setCursor(0,0);// Start the I2C interfaceWire.begin();}void loop() {//Set the menu item or display text for the usersetMenu();// read the buttonslcd_key = read_LCD_buttons();// check the blink counter isn"t too highif (blinkInt > maxBlinkInt){blinkInt=maxBlinkInt;}// Set the current blink statusif (currentMode>modeSHOWALARM2 && ((millis()-blinkStart)>blinkDelay)){blinkNow=!blinkNow;blinkStart=millis();}else if (currentMode<=modeSHOWALARM2){blinkNow=false;}// check the key press against the previous key press to avoid issues from long key pressesif (oldKey!=lcd_key) {// depending on which button was pushed, we perform an actionswitch (lcd_key){case btnRIGHT:{oldKey = btnRIGHT;if (blinkInt
Reading the tips and tricks from the BaldEngineer I noticed that it was best to send a full line of text to the LCD to overwrite everything as it can sometimes leave some cells with text. For example, if I sent a line saying 108 and then updated with text saying 22 it would actually say 228 because the LCD wouldn"t overwrite the 8 at cell 3.
The solution is to create a function to write the text to the LCD:void displayText(String line0Text, String line1Text){lcd.setCursor(0,0);sprintf(line0,"%-21s", line0Text.c_str());lcd.print(String(line0));lcd.setCursor(0,1);sprintf(line1,"%-21s", line1Text.c_str());lcd.print(String(line1));}
There was also an issue with sending numbers to the LCD, they would only ever show up as the figure 10. This was resolved with another function that I copied from the internet where it is often cited and resolves the issue:String twoDigitNumber(byte number){char buffer[3];snprintf(buffer,sizeof(buffer), "%02d", number );return String(buffer);}
This is so that the DateText and TimeText can be reused when adjusting the date and time. They read the value of blinkInt and the state of the blinkNow to determine if some of the text should be hidden to give the impression of blinking.String dateText() {String result="Date: ";if (blinkInt!=1 || blinkNow==false){result+=twoDigitNumber(Clock.getDate());}else{result+=" ";}result+="/";if (blinkInt!=2 || blinkNow==false){result+=twoDigitNumber(Clock.getMonth(Century));}else{result+=" ";}result+="/";if (blinkInt!=3 || blinkNow==false){result+=twoDigitNumber(Clock.getYear());}else{result+=" ";}return result;}String timeText() {String result="Time: ";if (blinkInt!=1 || blinkNow==false){result+=twoDigitNumber(Clock.getHour(h12, PM));}else{result+=" ";}result+=":";if (blinkInt!=2 || blinkNow==false){result+=twoDigitNumber(Clock.getMinute());}else{result+=" ";}result+=":";result+=twoDigitNumber(Clock.getSecond());return result;}void showDateTime(){displayText(dateText(), timeText());}
The two separate functions called setDate and setTime simple adjust the display and set the maxBlink variable. For the time I"ve not made an allowance for setting seconds manually, when minutes are changed seconds automatically go to 0. I don"t need a clock to be that accurate, if you do you could easily alter this but you might need to account for lag in processing the command.void setDate(){displayText("Set the date:", dateText());maxBlinkInt=3;}void setTime(){displayText("Set the time:", timeText());maxBlinkInt=2;}
It is the up, down and right buttons that call the necessary functions to change the date and time. The right buttons changes the blinkInt valuecase btnRIGHT:{oldKey = btnRIGHT;if (blinkInt
The up and down buttons adjust the valuescase btnUP:{oldKey = btnUP;if (currentMode==modeSETDATE){if (blinkInt==1){increaseDate();}if (blinkInt==2){increaseMonth();}if (blinkInt==3){increaseYear();}}if (currentMode==modeSETTIME){if (blinkInt==1){increaseHour();}if (blinkInt==2){increaseMinute();}}case btnDOWN:{oldKey = btnDOWN;if (currentMode==modeSETDATE){if (blinkInt==1){decreaseDate();}if (blinkInt==2){decreaseMonth();}if (blinkInt==3){decreaseYear();}}if (currentMode==modeSETTIME){if (blinkInt==1){decreaseHour();}if (blinkInt==2){decreaseMinute();}}
The functions to increase the various date and time parts use the DS3231 library. One of the decisions I made here was to keep scrolling through potential values rather than going to a dead end. For example, for minutes, instead of stopping at 59 and having to go down again to get to 0 I simply allow the sequence to go from 59 to 0. I also factor for the maximum days in a month, not just when setting days but also when setting months or years, just in case the day is set to 31 and the user adjusts to a month that only has 30 days or less. Leap years are adjusted for as well./**************************************************************** Functions to increase and decrease time elements***************************************************************/void increaseYear(){Year=Clock.getYear();if (Year<99){Year = Year + 1;}else{Year = 00;}Clock.setYear(Year);if (Clock.getDate()>monthMaxDays(Clock.getMonth(Century))){Clock.setDate(monthMaxDays(Clock.getMonth(Century)));}}void decreaseYear(){Year=Clock.getYear();if (Year>1){Year = Year - 1;}else{Year = 99;}Clock.setYear(Year);if (Clock.getDate()>monthMaxDays(Clock.getMonth(Century))){Clock.setDate(monthMaxDays(Clock.getMonth(Century)));}}void increaseMonth(){Month=Clock.getMonth(Century);if (Month<12) {Month = Month + 1;}else{Month = 1;}Clock.setMonth(Month);if (Clock.getDate()>monthMaxDays(Clock.getMonth(Century))){Clock.setDate(monthMaxDays(Clock.getMonth(Century)));}}void decreaseMonth(){Month=Clock.getMonth(Century);if (Month>1) {Month = Month - 1;}else{Month = 12;}Clock.setMonth(Month);if (Clock.getDate()>monthMaxDays(Clock.getMonth(Century))){Clock.setDate(monthMaxDays(Clock.getMonth(Century)));}}void increaseDate(){Date=Clock.getDate();if (Date
Setting the alarms on or off was fairly simple, there are three functions available in the DS3231 library. These are turnOnAlarm, turnOffAlarm and checkAlarmEnabled. I used the checkAlarmEnabled function to decide if the user needed to see the displays to set the rest of the alarm, if the user had turned the alarm off this all seemed redundant.case btnSELECT:{blinkInt=1;oldKey = btnSELECT;if (currentMode==modeSHOWDATETIME){currentMode=modeSETDATE;}else if (currentMode==modeSHOWALARM1){currentMode=modeSETALARM1ON;}else if (currentMode==modeSHOWALARM2){currentMode=modeSETALARM2ON;}else if (currentMode==modeSETDATE){currentMode=modeSETTIME;}else if (currentMode==modeSETTIME){currentMode=modeSHOWDATETIME;}else if (currentMode==modeSETALARM1ON && Clock.checkAlarmEnabled(1)){currentMode=modeSETALARM1;}else if (currentMode==modeSETALARM1ON && !Clock.checkAlarmEnabled(1)){currentMode=modeSHOWALARM1;}else if (currentMode==modeSETALARM1){currentMode=modeSETALARM1METHOD;}else if (currentMode==modeSETALARM1METHOD){currentMode=modeSHOWALARM1;}else if (currentMode==modeSETALARM2ON && Clock.checkAlarmEnabled(2)){currentMode=modeSETALARM2;}else if (currentMode==modeSETALARM2ON && !Clock.checkAlarmEnabled(2)){currentMode=modeSHOWALARM2;}else if (currentMode==modeSETALARM2){currentMode=modeSETALARM2METHOD;}else if (currentMode==modeSETALARM2METHOD){currentMode=modeSHOWALARM2;};break;}
The blinking was set to match the currently selected on or off option.void setAlarmOnOff(int alarmNum){if (alarmNum>0 && alarmNum<3) {maxBlinkInt=1;if(Clock.checkAlarmEnabled(alarmNum)){blinkInt=2;}else {blinkInt=1;}if (blinkInt==1 && blinkNow==true){displayText("", "Alarm" + String(alarmNum) + ": ON");}else if (blinkInt==2 && blinkNow==true){displayText("Alarm" + String(alarmNum) + ": OFF", "");}else{ displayText("Alarm" + String(alarmNum) + ": OFF", "Alarm" + String(alarmNum) + ": ON");}}}
The alarm is then set:void AlarmOn(int alarmNum, bool setOn){if (alarmNum>0 && alarmNum<3) {if (setOn){Clock.turnOnAlarm(alarmNum);}else {Clock.turnOffAlarm(alarmNum);}}}
There are now only two other options for each alarm that we can use to help with displaying and setting the alarms:getA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);setA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);getA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);setA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);
I created two separate functions for changing the day/date options and for changing the time for simplicity of reading the code:void changeAlarmDayOption(int alarmNum){byte ADay, AHour, AMinute, ASecond, ABits;bool ADy, A12h, Apm;//Collect the current alarm settingsif (alarmNum==1){Clock.getA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);}if (alarmNum==2){Clock.getA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);}ADy=!ADy;if (ADy && ADay>7) {ADay=7;}//Reset the alarm settingsif (alarmNum==1){Clock.setA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);}if (alarmNum==2){Clock.setA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);}}void ChangeAlarm(int alarmNum, int dayAdjust, int hourAdjust, int minAdjust,int secAdjust){byte ADay, AHour, AMinute, ASecond, ABits;bool ADy, A12h, Apm;//Collect the current alarm settingsif (alarmNum==1){Clock.getA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);}if (alarmNum==2){Clock.getA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);}//Adjust the dateADay+=dayAdjust;if (ADy){if (ADay<1){ADay=7;}if (ADay>7){ADay=1;}}else {if (ADay<1){ADay=31;}if (ADay>31){ADay=1;}}//Adjust the hourAHour+=hourAdjust;if (AHour<0){AHour=23;}if (AHour>23){AHour=0;}//Adjust the minuteAMinute+=minAdjust;if (AMinute<0){AMinute=59;}if (AMinute>59){AMinute=0;}//Adjust the secondif (alarmNum==1){ASecond+=secAdjust;if (ASecond<0){ASecond=59;}if (ASecond>59){ASecond=0;}}//Reset the alarm settingsif (alarmNum==1){Clock.setA1Time(ADay, AHour, AMinute, ASecond, ABits, ADy, A12h, Apm);}if (alarmNum==2){Clock.setA2Time(ADay, AHour, AMinute, ABits, ADy, A12h, Apm);}}
All of the previous steps were fairly painless, a bit of research and applying what I"d learnt. Not so with setting the alarm modes. This was a headache.
The alarm modes are held in memory in various locations and the DS3231 kindly collects this data, stores it in a byte and returns it to the user. In the previous codes this is the ABits variable.
There are a set of masks stated on the data sheet and I copied the constants fromhttps://github.com/mlepard/ArduinoChicken/blob/master/roboCoop/alarmControl.ino// These are the ALARM Bits that can be used// They need to be combined into a single value (see below)// Found here: https://github.com/mlepard/ArduinoChicken/blob/master/roboCoop/alarmControl.ino#define ALRM1_MATCH_EVERY_SEC 0b1111 // once a second#define ALRM1_MATCH_SEC 0b1110 // when seconds match#define ALRM1_MATCH_MIN_SEC 0b1100 // when minutes and seconds match#define ALRM1_MATCH_HR_MIN_SEC 0b1000 // when hours, minutes, and seconds match#define ALRM1_MATCH_DY_HR_MIN_SEC 0b0000 // when hours, minutes, and seconds match#define ALRM2_ONCE_PER_MIN 0b111 // once per minute (00 seconds of every minute)#define ALRM2_MATCH_MIN 0b110 // when minutes match#define ALRM2_MATCH_HR_MIN 0b100 // when hours and minutes match
Some places on-line suggest that you have to create a seven digit byte and set both alarms 1 and 2 at the same time. I discovered this isn"t so from reading the DS3231 library. The alarm 1 reads the first four (from the right hand) digits of a byte sent to it, alarm2 reads digits 5, 6, & 7.
I was still hitting problems though. Sometimes the scrolling of the current status would work, sometimes the status would update, sometimes it wouldn"t.
After posting online in the forum (https://forum.arduino.cc/index.php?topic=719176.0) cattledog highlighted that I could have dirty bytes that could be corrupting what I was sending to the DS3231 library. I explicitly set the bytes, made sure I didn"t recall an old byte variable, and it all worked.void setAlarmMethod(int alarmNum){if (alarmNum>0 && alarmNum<3) {if (alarmNum==1){maxBlinkInt=1;showAlarmMethod(1);}if (alarmNum==2){maxBlinkInt=1;showAlarmMethod(2);}}}void showAlarmMethod(int alarmNum) {String myString1="";String myString2="";byte ADay, AHour, AMinute, ASecond, ABitsOP=0b0;bool ADy, A12h, Apm;if (alarmNum==1){myString1 = "Alarm 1 Method:";Clock.getA1Time(ADay, AHour, AMinute, ASecond, ABitsOP, ADy, A12h, Apm);ABitsOP = ABitsOP & 0b1111;if (ABitsOP==ALRM1_MATCH_EVERY_SEC) {myString2 = "Once per Second";}else if (ABitsOP==ALRM1_MATCH_SEC) {myString2 = "Seconds Match";}else if (ABitsOP==ALRM1_MATCH_MIN_SEC) {myString2 = "Min & Secs Match";}else if (ABitsOP==ALRM1_MATCH_HR_MIN_SEC) {myString2 = "Hr, Min & Sec Match";}else if (ABitsOP==ALRM1_MATCH_DY_HR_MIN_SEC) {myString2 = "Dy, Hr, Mn & Sec";}} else {Clock.getA2Time(ADay, AHour, AMinute, ABitsOP, ADy, A12h, Apm);myString1 = "Alarm 2 Method:";if ((ABitsOP>>4)==ALRM2_ONCE_PER_MIN) {myString2 = "Once per Minute";}else if ((ABitsOP>>4)==ALRM2_MATCH_MIN) {myString2 = "Match Minute";}else {myString2 = "Match Hour & Min";}}displayText(myString1 , myString2);}
In the changeAlarmMethod function to can see that:Abits is explicitly set to zeroFor Alarm1 Abits is then masked to return the first four digits (&0b1111).For Alarm2 Abits is pushed to the right four places to return only digits 5, 6 & 7 (>> 4).For both alarms a new variable is created to hold the new alarm mode to ensure there isn"t any contamination of data from the old variableFor Alarm2 the new variable is pushed to the left four places to correctly set digits 5, 6 & 7 (>> 4).void changeAlarmMethod(int alarmNum, int dir) {byte ADay1, AHour1, AMinute1, ASecond1, ADay2, AHour2, AMinute2, ABits=0b0;bool ADy1, A12h1, Apm1, ADy2, A12h2, Apm2;int AlarmBits;if (alarmNum==1){Clock.getA1Time(ADay1, AHour1, AMinute1, ASecond1, ABits, ADy1, A12h1, Apm1);ABits = ABits & 0b1111;if (dir == 1) {if (ABits==ALRM1_MATCH_EVERY_SEC) {AlarmBits |= ALRM1_MATCH_SEC;}else if (ABits==ALRM1_MATCH_SEC) {AlarmBits |= ALRM1_MATCH_MIN_SEC;}else if (ABits==ALRM1_MATCH_MIN_SEC) {AlarmBits |= ALRM1_MATCH_HR_MIN_SEC;}else if (ABits==ALRM1_MATCH_HR_MIN_SEC) {AlarmBits |= ALRM1_MATCH_DY_HR_MIN_SEC;}else if (ABits==ALRM1_MATCH_DY_HR_MIN_SEC) {AlarmBits |= ALRM1_MATCH_EVERY_SEC;}}else if (dir == 0) {if (ABits==ALRM1_MATCH_EVERY_SEC) {AlarmBits |= ALRM1_MATCH_DY_HR_MIN_SEC;}else if (ABits==ALRM1_MATCH_SEC) {AlarmBits |= ALRM1_MATCH_EVERY_SEC;}else if (ABits==ALRM1_MATCH_MIN_SEC) {AlarmBits |= ALRM1_MATCH_SEC;}else if (ABits==ALRM1_MATCH_HR_MIN_SEC) {AlarmBits |= ALRM1_MATCH_MIN_SEC;}else {AlarmBits |= ALRM1_MATCH_HR_MIN_SEC;}}else {AlarmBits |= ABits;}Clock.setA1Time(ADay1, AHour1, AMinute1, ASecond1, AlarmBits, ADy1, A12h1, Apm1);} else {Clock.getA2Time(ADay2, AHour2, AMinute2, ABits, ADy2, A12h2, Apm2);ABits = ABits >> 4;if (dir == 1) {if (ABits==ALRM2_ONCE_PER_MIN) {AlarmBits = ALRM2_MATCH_MIN;}else if (ABits==ALRM2_MATCH_MIN) {AlarmBits = ALRM2_MATCH_HR_MIN;}else {AlarmBits = ALRM2_ONCE_PER_MIN;}}if (dir == 0) {if (ABits==ALRM2_ONCE_PER_MIN) {AlarmBits = ALRM2_MATCH_HR_MIN;}else if (ABits==ALRM2_MATCH_HR_MIN) {AlarmBits = ALRM2_MATCH_MIN;}else {AlarmBits = ALRM2_ONCE_PER_MIN;}}AlarmBits = AlarmBits << 4;Clock.setA2Time(ADay2, AHour2, AMinute2, AlarmBits, ADy2, A12h2, Apm2);byte newBits;Clock.getA2Time(ADay2, AHour2, AMinute2, newBits, ADy2, A12h2, Apm2);}}
The constants used for the current status are shown below.// define some values used by the menu controllerconst int modeSHOWDATETIME = 0;const int modeSHOWALARM1 = 1;const int modeSHOWALARM2 = 2;const int modeSETDATE = 3;const int modeSETTIME = 4;const int modeSETALARM1ON = 5;const int modeSETALARM1 = 6;const int modeSETALARM1METHOD = 7;const int modeSETALARM2ON = 8;const int modeSETALARM2 = 9;const int modeSETALARM2METHOD = 10;int currentMode = modeSHOWDATETIME;
I"ve created a simple casing/holder for the shield and breadboard. it is 2-piece for two reasons. Firstly, the frame around the LCD would have needed supports and scondly, I"ve found that the positions of the buttons is a bit erratic and so this design allows anyone replicating the design to tweak the LCD panel. The stl files are included.
One of the tings I noticed with this code was the amount of memory it used. I"m not great at understanding how to control memory but I did a couple of things after I wrote the instructions above:I changed all #Define to const as I had read it was better for memory. It had limited effect.I changed all integer flags to bytes to reduce memory usage, this had some effect.I removed global variables where they could be local variables, again this had limited effect.
The next step with memory was to remove references to Serial from the SetUp function. This reduces the memory usage to 50% of storage and global variables occupying 30% of dynamic memory. So there is a lesson to comment out or remove all debugging statements once complete.
When I"ve used the RTC in projects I"ve found two issues:The status register of the DS3231 RTC doesn"t appear to clear correctly, locking the RTC alarm into a low state, this is resolved athttps://electronics.stackexchange.com/questions/445256/ds3231-stops-working-on-vbat
{"id":2520838307898,"title":"Diymore DS3231 AT24C32 IIC Precision Real Time Clock Memory Module for Arduino","handle":"diymore-ds3231-at24c32-iic-precision-real-time-clock-memory-module-for-arduino","description":"\u003cdiv\u003e\u003cspan\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eDS3231 is a low-cost, extremely accurate I2C real-time clock (RTC), with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, disconnect the main power supply and maintains accurate timekeeping. Integrated oscillator improve long-term accuracy of the device and reduces the number of components of the production line. The DS3231 is available in commercial and industrial temperature ranges, using a 16-pin 300mil SO package.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eRTC maintains seconds, minutes, hours, day, date, month, and year information. Less than 31 days of the month, the end date will be automatically adjusted, including corrections for leap year. The clock operates in either the 24 hours or band \/ AM \/ PM indication of the 12-hour format. Provides two configurable alarm clock and a calendar can be set to a square wave output. Address and data are transferred serially through an I2C bidirectional bus.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eA precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, provide a reset output, and if necessary, automatically switch to the backup power supply. In addition, \/ RST pin is monitored as generating μP reset manually.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eSave time and high precision addition, DS3231 also has some other features that extend the system host of additional features and a range of options.\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eThe device integrates a very precise digital temperature sensor, through the I2C * interface to access it (as the same time).\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eThis temperature sensor accuracy is ± 3 ° C. On-chip power supply control circuit can automatically detect and manage the main and standby power (i.e., low-voltage battery) to switch between the power supply.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eIf the main power failure, the device can continue to provide accurate timing and temperature, performance is not affected.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eWhen the main power re-power or voltage value returns to within the allowable range, the on-chip reset function can be used to restart the system microprocessor.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eModule parameters:\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e1 Size: 38mm (length) * 22mm (W) * 14mm (height)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e2 Weight: 8g\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e3 Operating voltage :3.3 - 5 .5 V\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e4 clock chip: high-precision clock chip DS3231\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e5 Clock Accuracy :0-40 ℃ range, the accuracy 2ppm, the error was about 1 minute\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e6 calendar alarm clock with two\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e7 programmable square-wave output\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e8 Real time clock generator seconds, minutes, hours, day, date, month and year timing and provide valid until the year 2100 leap year compensation\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e9 chip temperature sensor comes with an accuracy of ± 3 ℃\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e10 memory chips: AT24C32 (storage capacity 32K)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e11.IIC bus interface, the maximum transmission speed of 400KHz (working voltage of 5V)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e12 can be cascaded with other IIC device, 24C32 addresses can be shorted A0\/A1\/A2 modify default address is 0x57\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e13 with rechargeable battery LIR2032, to ensure the system after power failure, the clock move any natural normal\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e14 Packing: single anti-static packaging\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eWiring instructions (with Arduino uno r3 for example):\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eSCL → A5\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eSDA → A4\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eVCC → 5V\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eGND → GND\u003cbr\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003eNote\u003c\/strong\u003e: \u003cstrong\u003edon"t inclue battery,it only need 0.01 dollars,it"s not safty to ship by air mail.hope you can understanding\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003e(2) an electronic file data (including test procedures Arduino, PDF format schematics, data sheet)\u003cbr\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003ePackage Included:\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e1PC*DS3231 module\u003c\/span\u003e\n\u003c\/div\u003e","published_at":"2019-09-24T09:51:32+08:00","created_at":"2019-09-24T09:56:40+08:00","vendor":"diymore","type":"Clock Module","tags":["Arduino","UNO R3"],"price":2699,"price_min":2699,"price_max":2699,"available":true,"price_varies":false,"compare_at_price":null,"compare_at_price_min":0,"compare_at_price_max":0,"compare_at_price_varies":false,"variants":[{"id":23739202338874,"title":"Default Title","option1":"Default Title","option2":null,"option3":null,"sku":"X13720","requires_shipping":true,"taxable":true,"featured_image":null,"available":true,"name":"Diymore DS3231 AT24C32 IIC Precision Real Time Clock Memory Module for Arduino","public_title":null,"options":["Default Title"],"price":2699,"weight":0,"compare_at_price":null,"inventory_management":null,"barcode":"","requires_selling_plan":false,"selling_plan_allocations":[]}],"images":["\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_8_847.jpg?v=1588664386","\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_1_642.jpg?v=1588664386","\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_5_714.jpg?v=1588664386","\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_10_782.jpg?v=1588664386","\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_9_838.jpg?v=1588664386","\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_12_381.jpg?v=1588664386"],"featured_image":"\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_8_847.jpg?v=1588664386","options":["Title"],"media":[{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679434526791,"position":1,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_8_847.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_8_847.jpg?v=1588664386","width":1000},{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679435444295,"position":2,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_1_642.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_1_642.jpg?v=1588664386","width":1000},{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679435903047,"position":3,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_5_714.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_5_714.jpg?v=1588664386","width":1000},{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679436001351,"position":4,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_10_782.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_10_782.jpg?v=1588664386","width":1000},{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679436656711,"position":5,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_9_838.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_9_838.jpg?v=1588664386","width":1000},{"alt":"Diymore Ds3231 At24C32 Iic Precision Real Time Clock Memory Module For Arduino","id":6679437180999,"position":6,"preview_image":{"aspect_ratio":1.0,"height":1000,"width":1000,"src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_12_381.jpg?v=1588664386"},"aspect_ratio":1.0,"height":1000,"media_type":"image","src":"https:\/\/cdn.shopify.com\/s\/files\/1\/0122\/7558\/0986\/products\/X13720_12_381.jpg?v=1588664386","width":1000}],"requires_selling_plan":false,"selling_plan_groups":[],"content":"\u003cdiv\u003e\u003cspan\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eDS3231 is a low-cost, extremely accurate I2C real-time clock (RTC), with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, disconnect the main power supply and maintains accurate timekeeping. Integrated oscillator improve long-term accuracy of the device and reduces the number of components of the production line. The DS3231 is available in commercial and industrial temperature ranges, using a 16-pin 300mil SO package.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eRTC maintains seconds, minutes, hours, day, date, month, and year information. Less than 31 days of the month, the end date will be automatically adjusted, including corrections for leap year. The clock operates in either the 24 hours or band \/ AM \/ PM indication of the 12-hour format. Provides two configurable alarm clock and a calendar can be set to a square wave output. Address and data are transferred serially through an I2C bidirectional bus.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eA precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, provide a reset output, and if necessary, automatically switch to the backup power supply. In addition, \/ RST pin is monitored as generating μP reset manually.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eSave time and high precision addition, DS3231 also has some other features that extend the system host of additional features and a range of options.\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eThe device integrates a very precise digital temperature sensor, through the I2C * interface to access it (as the same time).\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eThis temperature sensor accuracy is ± 3 ° C. On-chip power supply control circuit can automatically detect and manage the main and standby power (i.e., low-voltage battery) to switch between the power supply.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eIf the main power failure, the device can continue to provide accurate timing and temperature, performance is not affected.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eWhen the main power re-power or voltage value returns to within the allowable range, the on-chip reset function can be used to restart the system microprocessor.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003e\u003cspan\u003eModule parameters:\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e1 Size: 38mm (length) * 22mm (W) * 14mm (height)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e2 Weight: 8g\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e3 Operating voltage :3.3 - 5 .5 V\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e4 clock chip: high-precision clock chip DS3231\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e5 Clock Accuracy :0-40 ℃ range, the accuracy 2ppm, the error was about 1 minute\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e6 calendar alarm clock with two\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e7 programmable square-wave output\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e8 Real time clock generator seconds, minutes, hours, day, date, month and year timing and provide valid until the year 2100 leap year compensation\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e9 chip temperature sensor comes with an accuracy of ± 3 ℃\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e10 memory chips: AT24C32 (storage capacity 32K)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e11.IIC bus interface, the maximum transmission speed of 400KHz (working voltage of 5V)\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e12 can be cascaded with other IIC device, 24C32 addresses can be shorted A0\/A1\/A2 modify default address is 0x57\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e13 with rechargeable battery LIR2032, to ensure the system after power failure, the clock move any natural normal\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e14 Packing: single anti-static packaging\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eWiring instructions (with Arduino uno r3 for example):\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eSCL → A5\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eSDA → A4\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eVCC → 5V\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eGND → GND\u003cbr\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003eNote\u003c\/strong\u003e: \u003cstrong\u003edon"t inclue battery,it only need 0.01 dollars,it"s not safty to ship by air mail.hope you can understanding\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003e(2) an electronic file data (including test procedures Arduino, PDF format schematics, data sheet)\u003cbr\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003ePackage Included:\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e1PC*DS3231 module\u003c\/span\u003e\n\u003c\/div\u003e"}
If you receive a product with a manufacturing defect, please notify us within the 3 days of you receive the product, supported by proper pictures and description. Once our support team accept the return, we will provide a replacement or a complete refund including the return shipping cost. Please note that if your item is already soldered or modified in manner we will not be able to take it under return.
We don"t accept the returns for the products damanged by improper use of the product. Moreover we don"t accept the return, if the ordered product is not fit for any specific application. Please read the product specifications and datasheet before selecting and ordering a product. Returns are accepted only with 3 days from the date of delivery.
We ship to all over India with free shipping on all prepaid orders. For Cash on Delivery orders INR 70 will be charged for orders below INR 599 and INR 20 will be charged for the orders above 599. Please contact to our support team at support@quartzcomponents.com for any question related to shipping.
Ms.Josey 
Ms.Josey