Abstract—This article describes an interesting and inexpensive laboratory experiment for undergraduate students of electronics, geography and related disciplines. The objective of the proposed experiment is to improve the students’ exposure on the basic principles of instrumentation and to demonstrate an electronic measurement system. A simple electronic curvy length measurement system is presented here. Such a system can be used to measure curvy lengths e.g. length of a river, road or railway line etc. from topographical map. The proposed system is composed of simple functional blocks which are usually demonstrated in laboratory or in theory course of electronics at the undergraduate level. The experiment is assigned to a group of students and it is found that the experiment can fulfill its objectives with high degree of satisfaction. Keywords—Curvy length measurement, Education, Electronics, Laboratory experiment, Topographical map. I. INTRODUCTION ABORATORY experiments are the major source of knowledge for educating students in science disciplines. Cost effectiveness of experimental setup and learning deliverables are the key factors in adapting any laboratory experiment into students’ curriculum. For students of electronics, geography and related disciplines, an effective laboratory experiment is proposed in this work. The main objective of this work is to propose an efficient laboratory experiment on electronic measurement system at the undergraduate or postgraduate level. By performing the proposed experiment, students will gain hand-on-experience about the (i) role of various functional blocks or elements and their interfacing in instrumentation, (ii) construction of a simple measurement system, (iii) various features of electronic measurement system etc. To measure the length of curvy line on a map, mechanical rotameter, curvimeter, map-measurer, opisometer etc. are commonly used. Today, electronic map measurers (with high level of precision) are also available commercially. However, the objective of the present work is to demonstrate a cost effective simple curvy length measurement system as a laboratory experiment for undergraduate students. Further, it is to be noted that, simple experiment which provides direct application, delivers better learning impacts. All the functional blocks of the proposed system are commonly taught in theory (or laboratory) at the undergraduate level. Hence, simple Arijit Roy and Dibyendu Chatterjee both are with the Department of Electronics, West Bengal State University, Barasat, Kolkata, India 700126 (Phone: +91-9051503636; e-mail: arijitroy@live.com). Sharmistha Roy is with Asutosh College, Kolkata, India 700026 (Phone: +91-9874758375; e-mail: sharmistharoy29@gamil.com). components which are easy to assemble in laboratory are proposed to construct the measurement system. An electro-mechanical rotary encoder is used as a primary sensor for the proposed system. This type of rotary encoder is often found in computer mouse as a scroll wheel. A shaft- wheel system provides switching which in turn constitutes the encoder. The wheel is moved along the target curvy line. The rotation of the encoder wheel produces electronic pulses. These pulses are filtered, shaped and then counted. In order to count the number of pulses generated by the encoder, a mod- 100 counter is constructed. For data presentation, two-digit seven segment display is used. The above mentioned concept of measuring curvy length is implemented using simple laboratory components. The functional blocks of the system is described in detail. The entire system is tested, verified and presented. II. ELECTRONICS CURVY LENGTH MEASUREMENT SYSTEM The proposed electronic measurement system consists of very simple functional blocks which are commonly used in instrumentation. Similar to many other electronic measurement systems, this electronic system consists of (i) Primary sensing element, (ii) Signal conditioning element, (iii) Data collection element, (iv) Data presentation element. In terms of functional blocks, the entire system is shown in Fig. 1. The description on each of these blocks of the system is presented in subsequent sections. Fig. 1 Block diagram of the proposed system A. Primary Sensing Element An electro-mechanical rotary encoder is used for primary sensing element. The electro-mechanical rotary encoder basically acts a rotary switch [1]. The scroll wheel of computer mouse is one of the simplest electro-mechanical rotary encoders. Such an encoder is schematically shown in Fig. 2. The encoder consists of three terminals for electrical connection. These terminals are labeled as A, C and B as shown in Fig. 2. At stationary condition, there are no contacts made by the encoder between the terminals A, B, C (see Fig. 2). During the rotation of the shaft, the terminal C first makes contact to the terminal A and then to the terminal B. Next, the contact between the terminals C and A breaks and then the A Simple Electronic Curvy Length Measurement System: Application to Geography Arijit Roy, Sharmistha Roy, Dibyendu Chatterjee L World Academy of Science, Engineering and Technology International Journal of Electrical, Electronic Science and Engineering Vol:8 No:4, 2014 35 International Science Index Vol:8, No:4, 2014 waset.org/Publication/9998015