CDR Samples

CDR CAREER EPISODE 1

Introduction

CE1.1 This career episode will discuss the academic project that I did in my second year at Jawaharlal Nehru Technological University while studying for the Bachelor of Technology in Electrical and communication Engineering. The project was the development of the GSM BASED LPG MONITORING SYSTEM.I handled this project between May 2011 and October 2011at the department of electrical and communication engineering laboratory at Hyderabad, Telangana, India. My duty was to completed the project and make a presentation to the faculty members.

Background

CE1.2 Fuel has always been a center of debate withrespect to environment friendliness and performance. Liquid Petroleum gas is a very important type of fuel. This is because of the various desirable properties associated with it including being smoke and soot free as well as being a clean energy source. However, it poses a risk to fire hazard when it leaks into the air unmonitored. And accidents associated with it are deadly and often uncontrollable. Systems are continually being developed to address this issue.Existing systems have not fully tackled the issue. This project factors in telecommunications in control of real life parameters.

CE1.3 objective of this project was to determine the levels of in a given environment being monitored. To use the LPG gas sensor to detect high levels ofconcentration of LPG in the environment being monitored. To trigger alarm by sending a signal to actuate buzzer and LED and to send an SMS to the owner via a dedicated number. To display via the LCD and show the necessary actions to be taken. To actuate fans to dispel the air and reduce concentration of the gas to acceptable volumes.

 Figure 1: organization chart.

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CE1.4 During the development of the project I performed various roles including the following;

  1. Research in the existing systems of LPG gas control in order to identify means and ways to improve and come up with a better system
  2. Data collection by visiting various LPG gas distributioncenter=res and hazard management systems
  3. Analysis of the obtained data and to develop an improved system
  4. Design and modelling of the system
  5. Fabrication of the prototype
  6. Testing of the system and hardware
  7. Documentation

Personal Engineering Activity

CE1.5 To successfully execute all phases of project development I prepared adequately by conducting a thorough research into the many forms of controlling and minimizing dangers posed by LPG. This involved reading widely and viewing development and discoveries on the same topic.I also utilized the lecture notes on Cellular and mobile communications, and the Microcontrollers and it applications. The units were very helpful because they constituted the core of the project functionalities. I restricted my working to Indian Standards governing microcontroller based systems and also International Standards to ensure that every stage of development would comply with regulations.

CE1.6 The projects were to be completed within the academic year. This called for proper organization and planning. I hence generated a well-articulated time schedule highlighting major task and the respective timeline for execution. I also set off looking for relevant information. I visited licensed LPG gas distributors and engaged them in surveys and interviews to aid me in coming up with the design. I reviewed various gas detection systems and tools that were already deployed in premises and industries in order to identify areas of improvement. I well noted down the findings which became my basic data for starting the project development.

CE1.7 Upon obtaining adequate data and information, I embarked on designing the system. This was boosted by the relevant information which dictated the design procedures and decisions.

Figure 2: Flow Chart of the System

CE1.8 The flow chart above enabled me to further identify the various components and systems within the design for consideration. The gas sensor serves to monitor the ambient gas levels. Upon detection of LPG gas at some threshold concentration, it would send a notification to the microcontroller LPC2148 microcontroller. The microcontroller is the brain of the system and has been program on the actions to execute chronologically. On receiving a high signal from the sensor, it would actuate the audio visual alarm, to notify the residents within the premise. A signal would also be generated and sent to GSM modem to send a message to the owner. At the same instance, the relay timing circuit would be instructed to switch on the exhaust fan. Eventually, I obtained the overall system block diagram s shown below;

Figure 3: The System Block Diagram

CE1.9 Deriving the above specific and correct components was quite a task. This was due to the calculations involved to ensure that system sensitivity and performance would be optimal.The sensing component would be a resistance based device whose resistance varies according to level of gas in the environment. Therefore, to set the upper and lower limits, it was proper to demarcate the range of resistance variation and to pinpoint the point beyond which the system must automatically activate.The formula below was used to achieve design values;

 Where:

  1. Rs – the sensor resistance
  2. Vc – the supply voltage to load cell
  3. VRL – the voltage across load resistance
  4. RL – the load resistance

CE1.10 The development process was not without a challenge. However, this was part of troubleshooting and determination of best suited components. First was the sensor which would trigger even with non LPG gas concentration. To overcome this serious issue, I had to look out for the most sensitive sensor according to design, where I resorted to use Gas detection module with extra filtering to discriminate the gas for sensing. The other challenge was delay in sending of the message. A delay of about two minutes was recorded. Because time is a crucial factor in LPG accidents, this had to be real time. After troubleshooting, the program was debugged and the system could the respond as required

CE1.11 Upon successful design, I simulated and modeled the system to check performance and achievement of the objectives. After correcting the challenges of false triggering and delay, I obtained the components based on the specification and system requirement. Assembling and fabrication then kicked off. The various sub-units, Sensor, microcontroller, actuators – GSM modem, relay driving circuit, alarm response, and display units. Were assembled and tested systematically and finally combined and the whole system tested for compatibility and response. The hardware was the fabricated and packaged after posts fabrication tests were done.

CE1.12 Innovation was key in this project. This was necessary because the systems in the market were below bar in sensitivity. The gas sensing module was filtered to ensure that it would only be triggered by LPG only but no other gases. This way false alarms were eradicated. This is because security of such systems must be assured. Alarm must have activated when expected and not activate when not supposed to.

CE1.13 The success of the stages above was closely linked to the tools and software used. Computer aided design in this project included use of Embedded C to develop the command program for the microcontroller. Proteus was used to simulate the input/output responses and debug the system before final fabrication could be done. At some point Arduino Uno was employed specially to improve the time of response for message sending

CE1.14 I ensured that referencing and innovation in the future would be possible by documenting the project. Phase by phase reports were compiled to document the whole project. The various chapters covered included an introduction of the project. Here, objectives and importance of the system were covered. Literature review was put down to appreciate previous related works and to give a way forward in the innovative design. Design and construction was included to give a simplified step by step procedures of analysis and design. Conclusion and recommendation wound up the document whereby the success of the system was evaluated and possible improvements were captured respectively.

CE1.15 A successful project is complete with proper and thorough documentation. I therefore conducted documentation right from start of project through to the end. Beginning with the first chapter of introduction. Wherein I covered the concept matter and explained the objectives and purpose of the project. Literature review followed suit, the analysis and design phase write up. Penning off was by recommendation and conclusion.

CE1.16 I collaborated with fellow classmates from inception through completion of theproject. Their input especially in brainstorming and critiquing became helpful in designing and implementing the project. The assistance of lecturers and the project tutor was sobering into choosing quality and economical components. While conducting the survey and meeting new people, I had to employ the interpersonal skills in order to enhance communication and collection of useful information.

CE1.17 An economical consideration in this project was in the comparison of prices of components as distributed and sold by various dealers. Through consultation and visiting the outlets to make enquiries, I selected the cheap but quality components so as not to compromise on the safety of equipment and users.This is because such a system operation has dire consequences and at all cost, proper functioning must be guaranteed. This however called economic consideration so as not to inflate the costs.

CE1.18 Planning was paramount towards achievement of the set objectives of the project. This ensured that all resources were properly utilized, ranging from time to finances to manpower. By having a projected time schedule, I was able to manage the limited time towards completing tasks phase by phase. By doing so, the project was complete weeks before the deadline of submission.Coordinating the manpower was equally a score because the contributions of the various parties was so harmonious and fruitful. I drew a budget and considered various cost items and cut down unnecessary expenditures. This would help not to burden buyers by throwing cost expenses on them.

CE1.19 I paid special attention to Wireless Communications and Networks and Cellular Mobile Communication Lecture notes and scholarly articles. They became a very vital source of valuable information which guided the design and implementation of the project. I attended workshops and seminars where gas fuels security was being addressed by variousconcerned groups. It was also very vital to consider the Indian National regulations on wireless systems for control inhighly sensitive and hazardous environments.

CE1.20 Safety of personnel and environment was considered by working within the limits of the international and national Indian standards for electronic components and LPG (explosive) gases regulations. While fabricating, the correct tools were used as well as protective gear was regarded.The security of the system, its ability to act when required was tested. Compatibility with other fire alarm systems was evaluated. This is because a falsely triggered can be as dangerous and could cause tragedy due to fear.

Summary

CE1.21 In summary, this project involved various phases of development of a system to detect LPG gas leakage. Beginning with research and brainstorming of ideas after data collection which led to settling upon this particular system. Designing of the various stages and components followed suit. The simulation and modelling was carried out to identify malfunctions of the system and to rectify before progressing to the next stage. The fabrication stage saw the implementation of a working system. When the system worked, it was in order to documents the processes and procedures to facilitate future referencing.