Tag Archives: RTC

MP3 Module & RTC DS1307 Shield For 28/40 Pin PIC Development Board

MP3 Shield has been designed for various applications related to voice record and play using MP3 module with memory card storage, this shield can be used as standalone mode or Digital mode by serial interface. In standalone mode it can play 16 messages with couple of other functions, Standalone operation possible by connecting resistors and push switches on ADC pins of the module check data sheet for switch connections. Digital mode provides full control of messages with serial interface. Shield also has DS1307 RTC on board to develop a taking clock or other time related applications. Board has dual audio outputs, single channel 3W direct speaker output from MP3 Module and On board 5W Stereo Amplifier based on BA5406 provided to Amplify low audio signal coming from MP3 module. 4 Tact switch with open header connector can be interface to any port of micro-controller using female to female wire harness. RC6, RC7 and RC5 pin connected to micro-controller for serial interface. DS1307 RTC pins are connected to RA0 and RA1 Port pins. Refer to datasheet for Module Serial Interface, switch connections circuit for stand-alone mode.

MP3 Module & RTC DS1307 Shield For 28/40 Pin PIC Development Board – [Link]

Pi Desktop Case – include peripherals too

The ‘Pi Desktop’ kit from element14 offers some great features like Wi-Fi, Bluetooth, a real-time clock, an interface for an mSATA-SSD hard drive, an optional camera, heat sink, a neat power switch and of course the sleek black case. [via]

The Raspberry Pi is a well designed, powerful and inexpensive board, but not a complete computer. Some distributors know you need more than just a plastic case and a mains-adapter power supply (or USB cable). The ‘Pi Desktop’ kit from element14 contains everything you need and more, turning your RPi into a fully fledged computer.

Pi Desktop Case – include peripherals too – [Link]

Real Time Clock On 20×4 I2C LCD Display with Arduino

Sometimes it may be necessary to use a display while making a hardware project, but the size and the type of the display may vary according to the application. In a previous project, we used a 0.96″ I2C OLED display, and in this project we will have an I2C 20×4 character display.

This tutorial will describe how to use 20 x 4 LCD display with Arduino to print a real-time clock and date.

Real Time Clock On 20×4 I2C LCD Display with Arduino – [Link]

A 32-BIT FISHINO board with WiFi, SD card, RTC, audio codec, LiPo and more

Boris Landoni @ open-electronics.org presents his 32bit Arduino Compatible board which has some nice features on board. He wrties:

Our prototyping board acquires a 32-bit processor and sets the bar high, towards demanding applications that may take full advantage of the WiFi support, of the RTC and of the SD-Card, that make Fishino stand out from the common Arduino UNO. Second installment.

A 32-BIT FISHINO board with WiFi, SD card, RTC, audio codec, LiPo and more – [Link]

Making An Arduino I2C Digital Clock

Using Adafruit’s 0.56″ 7-segment LED backpack and display and the DS1307 RTC (Real Time Clock) board, this tutorial will guide you to make a simple 4-digit clock that uses only 2 Arduino pins.

The 7-Segment Backpack is a combination of the LED display, header pins, and a PCB which need to be soldered together. The PCB contains a driver chip with a built in clock that multiplexes the display and constant-current drivers for ultra-bright consistent color.

This module uses I2C interface, which means it needs just two data pins to control the 4 digits instead of 14 pin, freeing up Arduino pins for other usages.

DS1307 is a battery-backed real time clock (RTC) that allows a microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. DS1307 breakout board also comes as a kit of parts to be soldered.

Building the digital clock

It is a simple process, connect the part as shown in the image, the red wire connected with 5V, black wire with GND, orange to A4 (SDA – data), yellow to A5 (SCL – clock).

Both RTC and 7-segment modules have an Arduino library, as normal with libraries, unzip the folders into your Arduino ‘libraries’ directory and then restart the Arduino IDE for it to pick them up.

Paste the following sketch into a new Arduino window and upload it to your board. It will set the RTC to the time at which the sketch was compiled and uploaded. So, if your computer picks up its time from the Internet, that will be pretty accurate.

#include <Wire.h>
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"
#include "RTClib.h"


Adafruit_7segment disp = Adafruit_7segment();

void setup()
 if (! RTC.isrunning())
   RTC.adjust(DateTime(__DATE__, __TIME__));

void loop()

int getDecimalTime()
 DateTime now = RTC.now();
 int decimalTime = now.hour() * 100 + now.minute();
 return decimalTime;

The full documentation of the project is reachable here.

$18 RTC Shield For Both Arduino UNO And Raspberry Pi 3

Time and date information may be essential requirements for developing a hardware project, such as registration systems, alarms, and smart pills box. These information can be obtained locally by RTC (Real Time Clock) and RTCC (Real Time Clock Calendar) circuits like DS1307 from Maxim Integrated.

Microchip, an embedded control solutions company, produced MCP7941X three-member family of low power RTCCs with EEPROM and SRAM. Each of MCP79411 and MCP79412 has a unique MAC address that can be programmed by the end user for the networking applications. MCP79411 uses 48-bit MAC address and MCP79412 uses 64-bit one. MCP79410 is suitable for non-network applications as it has the same features except the unique ID.

These integrated circuits are compatible with I2C™, include a battery switchover circuit for backup power, and use a low-cost 32.768 kHz crystal, providing time tracking in 12 or 24 hour format and two settable alarms to the second, minute, hour, day of the week, date or month. They also have programmable output pin which can be set as an alarm out or a selected frequency clock out.

MCP79410 Integrated Circuit
MCP79410 Integrated Circuit

MCP79410 has the following features:

  • Battery-Backed Real-Time Clock/Calendar (RTCC) with configuration of Hours, Minutes, Seconds, Day of Week, Day, Month, Year in 12/24 hour modes
  • Leap year compensated  to 2399
  • On-Chip Digital Trimming/Calibration with 1 PPM resolution and ±129 PPM range
  • Dual programmable alarms
  • Versatile output pin
    • Clock output with selectable frequency
    • Alarm output
    • General Purpose output
  • Power-Fail Time-Stamp, time logged on switchover to and from Battery Backup
  • 2-Wire serial interface, I2C™ compatible, clock frequency up to 400 kHz
  • 64 bytes battery-backed SRAM and 1Kb EEPROM memory user memory
  • 64-bit protected EEPROM area, robust write unlock sequence
  • Wide voltage range, operating voltage 1.8V to 5.5V and backup voltage 1.3V to 5.5V
  • Low Typical Timekeeping Current
  • Automatic Switchover to Battery Backup
MCP79410 Box Diagram
MCP79410 Box Diagram

Based on MCP79410, Futura Group Srl developed a RTC shield compatible with Arduino UNO and Raspberry Pi 3 Model B and it supports all of the functions needed to manage the MCP79410 circuit.

The shield PCB contains the MCP79410 chip, SMD components, CR2032 battery holder, male and female stripps, and three buttons. The three buttons are connected with the Arduino and Raspberry Pi and they are used for the configuration process.

The RTC Shield
The RTC Shield

There is also a library which allows you to use and program the shield easily. It contains three files, two of them are the functions and theirs declarations, and the third is a text file contains the keywords of public functions and theirs usage.

The shield is available for $18.5 (16.50€). You can order it from open-electronics store and have access to the libraries and example sketches.

Full documentation of the shield with its schematics and diagrams is available here.

Rubidium Disciplined Atomic Clock


Cameron Meredith build a real-time-clock module controlled by a rubidium frequency standard, and since it also includes a GPS clock he can track local time dilation effects by comparing the two.

An I2C multiplexer board allows for more than one RTC module (Since these have a hard coded I2C address you can normally only use one). I went for three – One tracking GPS time, another tracking the rubidium standard, and the last one as a control or reference clock – without compensation.

An arduino knock-off compares the relative delay between the pulse-per-second outputs from the Rubidium standard, Real Time Clocks, and GPS.

After some defined time divergence, the RTC aging compensation register is updated to refine or maintain overall agreement. Essentially herding the RTCs so that their output stays within bounded agreement with the Rubidium standard and GPS.

Rubidium Disciplined Atomic Clock – [Link]

Chrome Apps and serial port communication


Luca Dentella writes:

During the development of my electronic projects, I sometimes need to develop a graphical user interface (GUI) that talks using serial communication with the devices I create.

In the past, I usually chose to develop those interfaces in C# and using the .Net Framework; framework which allows a rapid development, offers great ways to customize the interface (for example the ability to use custom fonts as in the GUI for RTCSetup) and makes easy to access all the different graphical elements of the operating system, like the systray (cfr the GUI for Type4Me).

Chrome Apps and serial port communication – [Link]

DS1307 RTC Module


The module based on DS1307, The DS1307 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I²C, bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The DS1307 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply. Timekeeping operation continues while the part operates from the backup supply.


  • Supply 5V DC
  • Completely Manages All Timekeeping Functions
  • Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
  • 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes
  • Programmable Square-Wave Output Signal
  • Simple Serial Port Interfaces to Most Microcontrollers

DS1307 RTC Module – [Link]

0.8A step-up DC/DC converters in a tiny package


Torex Semiconductor’s XC9141/XC9142 series of 0.8A step-up DC/DC converters come with an input–output disconnection function (load disconnection function) to prevent malfunctioning during standby, and for device functionality that enables power supply to RTC.

When the output voltage is 3.3V, the IC can start from an input voltage of 0.9V with a resistance load of 100Ω, enabling use in devices driven by one alkaline or nickel-hydrogen battery. The input voltage range is 0.65V to 6.0V, and the output voltage range can be set from 1.8V to 5.5V (accuracy ±2.0%) in steps of 0.1V. A switching frequency of 1.2MHz or 3.0MHz can be selected to match the application.

0.8A step-up DC/DC converters in a tiny package – [Link]