Simple and Accurate Representation of Bangla Numerals by 10-Segment Display Compared to 8-Segment Display

In the field of electronic devices, Digital logic system plays an important role. The rapid development of digital technology makes faster and easier life of a human being. Working in a unique field also gives a lot of pleasure. In this paper a new approach is chosen to start a journey with digital electronics. In the Electronic World Bangla language is neglected. The Bangla digital display is designed for the people of Bangladesh. On the other hand, Bangla numerals have more curved corners in comparison to English numerals. To represent English numerals, 7-segment display is so popular because of its simplicity and accuracy. Unlike English numerals, designing of simple and accurate segmented representation of Bangla numerals is still a research area of Bangla processing. Bangle numerals have some limitations of using more segments in displaying Bangla numerals. So, in this paper a new model of 10-segment display is proposed for Bangla numerals to overcome these limitations.


Introduction
Electrical and Electronics equipments play an indispensable role in everyday life. The most preferable language for those equipments is English but most of the people of Bangladesh are illiterate. Hence, for them learning English is quite impossible. A unique finite segmented display is [1][2][3][4] required to display Bangla numerals. For English numerals, 7-segment display is already accepted and used for a long time to display English numerals. It is a matter of great hope that the researchers of Bangla processing proposed some methods to represent Bangla numerals in the last few years. As a result different display architectures using a finite number of segments have been proposed for displaying Bangla numerals. To find the optimum number of segments we must have done more researches to reduce displaying cost, save memory space and produce qualitative outlook. The proposed model used only 10-segment display to reduce display cost and save memory space of dot matrix display, also maintain the overall outlooks. To represent Bangla display only two fabricated bent segments have been used. The proposed segmented display also avoids segment overlapping, used an optimal number of segments, avoid an unwanted number of gaps between two consecutive characters, produce uniform numerals and improve the accuracy of representation. The rest of this paper is organized as follows. Section II briefly introduces the model which is used in Section IV to represent the Bangla numerals. The comparison between proposed model and existing model is presented in section III. Finally, the paper is concluded in Section V.

The Proposed 10-Segment Display Model
The proposed 10-segment display model is shown in the Fig.1. The segments are non-overlapping and labeled with specific alphabet. In this paper LEDs are used to illuminate the segments. For a definite digit, particular segments will be ON (HIGH) and the others will be OFF (LOW), so it is necessary to mark the segments which can be displayed all the Bangla numerals accurately and uniformly.

Comparison between Proposed Display and Existing Display
The comparison between existing 8-segment [5] display and proposed 10-segment display for some Bangla numerals are shown in following Fig.2   In the above displays there are changes between existing 8-segment display and 10-segment display for displaying seven. In existing 8-segment display the Bangla numeral seven is not similar with Sutonny numeral. But in 10segment display the Bangla numeral seven is approximately similar with Sutonny numeral. In the above displays there are changes between existing 8-segment display and 10-segment display for displaying nine. In existing 8-segment display the Bangla numeral nine is not similar with Sutonny numeral. But in 10-segment display the Bangla numeral nine is approximately similar with Sutonny numeral.

Functional Representation of Bangla Numeral for Both Models
As there are ten Bangla numerals. So, the segment decoding logic requires four [6][7][8] Binary Coded Decimal (BCD) input and 10-segment outputs. The truth table is depicted in Table 1 and Table 2.   In the above Table 1and 2, 1=High (active segment) and 0=Low (inactive segment).

Sum of Product Function for Each Segment in Both Model
The sum of product function of each segment is shown in Table 5 and Table 6, respectively. Table 5. Sum of product function of 10-segments.

Implementation of Our Proposed Model
Our proposed model is implemented by the following circuit diagram shown in Fig.4. In the below Fig.4, the output of the 555 Timer is applied to the decimal decade counter 4017. The LED display device will show the Bangla digit from zero to nine with respect to the decade counter 4017 inputs with the help of the 555 Timer. For example, for segment 'e' will be on for displaying 0, 5, 6 and 8 when the output Qo, Q5, Q6, Q8 of the 4017 active and corresponding transistors are biased to complete the circuit connection. On the other way, the segment 'a' which is on for displaying 0, 1, 3, 4, 5, 7, 9 and at this time the circuit connection already exist and segment will be remain on, So, we need to off that particular segment. For this purpose, Q6, Q8 output of the 4017 and corresponding transistors are biased so that the corresponding segment is short circuited and it will remain off.

Conclusion and Discussion
Unlike English numerals, the appearance of Bangla numerals is extremely dependent on the perfection of their curved corners. To design the segment, we used simple two angular to bend segments. In this paper the proposed 10-segment display, displaying all the Bangla numerals uniformly and accurately. The implementation of Bangla numerals 7 and 9 was a challenging issue for 8-segment display. In the existing 8-segment display there is a problem for displaying the Bangla numerals seven and nine uniformly and accurately. But the proposed 10-segment display overcomes these problems. In the proposed 10-segment display the Bangla numerals seven and nine are similar of the Sutonny seven and nine. So it is expected that this segment display may be used as an ideal circuit for displaying Bangla numerals.