1. INTRODUCTION

Digital wall clocks are nevertheless not too different from analog clocks. Digital clocks display time digitally. It handles the time functioning electronically rather than the mechanical basis as used in analog clocks. In addition to it, they are more reliable, accurate and precise in measuring time [1]. 

          As we had discussed earlier, digital wall clocks are installed in every public place to ensure the facilities of describing time. In this project, we are proposing a digital wall clock system for a particular classroom of an institution which focuses on describing date, time along with temperature and total attendance of the class. Basically, it will act as an information board displaying all the necessary details of the day including the attendance of the student present in the class . It will exclude the use of paper work and human efforts. It will ensure the chance of manual error in keeping track of daily attendance of each and every class [2]. In addition to it, this system will be more cost

effective as it reduces the manpower associated with the job of attendance management of students. On the other hand, the main function of temperature sensor is to measure temperature for various applications. It provide minute to minute update on the changing temperature of the day which helps student s/teachers to take It helps in maintaining laboratory temperature which is required for various scientific experiments [3].   

2. PROPOSED METHOD

The ESP-32 module handles all controlling tasks in this project. It basically communicates with a real time clock (RTC), GSM module and temperature sensor and displays the output on a seven-segment display[4]. RTC is used to keep track of time and is installed on every computer to keep track of time. Attendance is displayed with the help of GSM module. It takes input in the form of number determining the total present student in the class and represent it on seven segment display as the output. Temperature Sensor senses the atmospheric temperature and with the co-ordination of ESP-32 represent it on the seven-segment display [5]. 

The block diagram for the technique is mentioned below-

3. HARDWARE DESIGN

3.1 ESP-32

A line of inexpensive, low-power system-on-chip microcontrollers called ES ESP32 integrates Bluetooth in binary mode and Wi-Fi. The ESP32 series includes built-in antenna switches, RF baluns, power amplifiers, low-noise admit amplifiers, filters, and power-handling modules [5]. It uses either a TensilicaXtensa LX6 microprocessor in binary-core and single-core variations, an Xtensa LX7 binary-core microprocessor, or a single-core RISC-V microprocessor.

Fig. 1- ESP 32

The main operation processor's communication load is reduced by the ESP-32's ability to operate as a fully independent system or as a slave device to a host MCU. Through its SPI/ SDIO/ or I2C/ UART connections, the ESP-32 may connect to other systems to provide Wi-Fi and Bluetooth capability.

    It is capable of delivering dependable performance in industrial settings and has an operating temperature range of -40 to 125 degrees Celsius. ESP- 32's innovative estimate circuitry allows it to effectively erase external circuit imperfections and adapt to changes in the environment.

3.2 REAL TIME CLOCK

A real time clock (RTC) is a piece of technology that counts the seconds. Although computers, servers, and embedded systems are commonly mentioned when using the word, RTC is present in almost any electronic equipment that needs to maintain precise time of day [6].

Fig. 2- Real Time Clock

The majority of RTC use crystal oscillators, although some provide the option to use power line frequency. Typically, quartz clocks and timepieces operate at a frequency of 32.768 kHz, which is also the frequency of the crystal. Temperature has no effect on the size of the quartz tuning fork in these crystals, hence it has no effect on frequency.

Some of its features are described below-

1) Low power consumption (significant when flowing from alternate source)

 2) Frees the main network from time critical task

3) More precise than distinctive system

3.3 SEVEN SEGMENT DISPLAY

A seven-segment display (SSD), sometimes known as a seven-segment indication, is an alternative to the more intricate dot-matrix displays for displaying decimal numbers. Digital watches, electronic metres, and other electronic devices for presenting numerical data frequently use seven segment displays. The seven segments are arranged in a rectangle with one horizontal segment on the top, middle, and bottom, two perpendicular segments on each side, and seven total segments. The segments are denoted by the letters A to G, with the voluntary decimal point (sometimes known as a "eighth segment," or DP) being used to depict non-integer numbers [7].

Fig. 3- SEVEN SEGMENT DISPLAY

3.4 GSM MODULE

A GSM modem, also known as a GSM module, is a device that provides a wireless data connectivity to a network using the GSM mobile telephone technology. Mobile phones and other devices that communicate with mobile telephone networks use GSM modems. To identify their device to the network, they need SIMs [8].

Fig. 4- GSM MODULE

 These devices are light and fluent to operate as well as having an unexpectedly low power consumption for the volume of work they can do. Cellular couplings can be a quick and effective way to get started with SMS adverts in network monitoring solutions because a unique subscription to an individual service provider isn't needed. It handles access to SIM, speech encoding and decoding, signaling and distinct network related tasks.

4. SENSOR SECTION

4.1 TEMPERATURE SENSOR

This device uses a temperature sensor to show the ambient temperature. There are numerous different types of temperature sensors, but the most familiar way that's employed in their categorization is grounded on the mode of connection that includes contact and noncontact temperature sensors. exemplifications of contact sensors involve thermistors and thermocouples because their contact with the things they measure is direct, whereas noncontact type temperature sensors measure the heat source’s radiation. In this project we use non-contact kind of temperature sensor for measuring temperature [9].

Fig. 4- TEMPERATURE SENSOR

Table 1- comparison table showing modification in projects

5. RESULT

6. CONCLUSION

There are many different styles of digital clocks available nowadays. The majority of them are genuinely expensive and of poor quality. Since they are built with timer ICs like 555 timers, the majority of those cannot provide the time accurately for prolonged periods of time. Once more, certain digital clocks experience data loss. Every time the power supply turns off. However, the Real Time Clock module in our multipurpose digital wall clock that monitors system time and updates makes it accurate. It features a built-in power sensor circuit that recognises power outages and instantly switches to the battery supply that is integrated with the RTC in the event of one. While our created digital clock includes all of the time options and will also integrate the alarm option in the upcoming interpretation, the majority of the digital clocks in the requests do not cover all of the time functions. Still, a bonus feature of our digital wall clock is the temperature and attendance display. Therefore, this version of the digital clock is actually a reasonably priced, reliable, and well-equipped gadget for the market's continued demand.