Car Indicator Design - Designing and Building of a Circuit System - Report Example

CAR INDICATOR DESIGN Name Institution Instructor Date Introduction In this particular project, the design, simulation as well as building of a circuit that functions as a car direction indicator involved comprehensive research and selection of a preferred idea before obtaining a detailed design. The circuit system of the car indicator was expected to employ the use of electronic signals and controls. When the car is about to change direction either to the left or to the right a switch is activated. The activated switch measures the signals and currents in the circuit system, and then the headlights are electronically activated. A computerised electronic circuit system on the dashboard switches on or blinks the indicator lights (Grout, 2008). The indicator circuit system designed in this project was also expected to possess the sensing capabilities to be able to sense the current that flows through the circuit with a very small magnitude. The small magnitude of current is a representation of the resistance fraction, which results into the current referred to as the current sensing resistor. When the flow of current takes place, the development of a fraction of voltage is experienced across the resistor. However, this particular current is not sufficient to lead to the production of an appreciable drop in voltage across the devices in series with it. An op amplifier is used in the amplification of the small voltage into a signal that activates other indicator devices (Candela, 2009). Objective This project was expected to meet the specified objectives as follows: Designing and building of a circuit system to function as a car direction indicator using 555 timer Incorporation yellow lights that blink while indicating the driver’s intention of turning right or left Final design Several design ideas were considered before a final design was arrived at. The final circuit obtained in this project was broken down into smaller subsystems, which were separately described using block diagrams as indicated below. Bi-stable The bi-stable mode is also referred to as the Schmitt trigger mode. This kind of a timer functions as a simple flip-flop. In this particular case, the reset inputs as well as the trigger are held at a higher position through the pull-up resistor while the pin at the threshold input is left in a floating position. The configuration is such that when the trigger is shortly pulled towards the ground, the output pin is transitioned to a high state. When the pulling of the reset pin takes place towards the ground, it plays the role of resets, which is responsible for the transitioning of the output to a low state. In the case of a bi-stable configuration, there are no timing capacitors needed. The pin that controls voltage is linked to the ground through a capacitor with a small value that is between 0.01 uF and 0.1 uF. The pin 7, which is responsible for discharge, remains in a floating position (Grout, 2008). Block diagram of a bi-stable mode A stable In this particular mode, the timer presents a continuous and steady stream of pulses that are rectangular in nature and with a specific frequency. A resistor is linked in the middle of the discharge pin and the voltage VCC. Another resistor is in a position between the trigger and the discharge pin as well as the threshold pins having a common node. Therefore, the capacitor obtains charge through the resistors R1 and R2. The capacitor is then discharged through the resistor R2. The impedance within the pin 7 is low towards the ground and therefore it is discharged via the capacitor. In this a stable mode, the frequency of the pulse stream is dependent on the magnitudes of R1, R2 as well as C (Candela, 2009). Schematic diagram of a standard a stable circuit The final design system for the direction indicator circuit involved the incorporation of four systems of light direction indicator. In this system design, the intention of the driver to changer direction is signalled through winkers of a pair of yellow lights as front indicators and a pair of amber or red lights as rear indicators. The rate of flashing for the indicators lamps in this case were set at between 50 to 100 flashes in one minute. A flasher unit is was designed to ensure the production of current fluctuations thereby causing the blinking of the indicator lamps. The status of operation for the indicator lamps would be shown through the presence of a warning light on the dashboard. The switch for turn indicator was designed to operate as a self-cancelling switch, which is expected to lead the current to either left hand or right hand lamps. Two pairs of blinking lamps were mounted at both the front and rear parts of the vehicle in which case they were combined with the stop lamps as well as the side lamps. However, separate bulb filaments were used in each case (Kamal, 2007). Details of the final design The popular method employed in this electronic circuit design was dependent on a hot wire linear expansion, which is subjected to heating through the passing electric current. The flow of current takes place from the voltage source to the terminal marked as B then to the armature labelled C. From there it flows to through a hot wire to the resistance of ballast then to the contact labelled D through the wire around the iron core to the terminal labelled L. From here, the signal current is expected to flow back to the switch of the indicator. The current size and the resistor limit for the ballast resistance stops the lap from lighting. The hot wire is heated via the involvement of the flowing current (Candela, 2009). This elongated the wire activated the movement of the armature labelled C towards the iron core with the help of springs to close the contacts labelled D. More current pass through the resistance of the ballast and flows directly towards the contact labelled D. This is followed by a selection of a pair of lamps enabling them to flash. Build of final design The building of the final design employed the use of breadboards, which played significant role in demonstrating the detail, and elements of the indicator circuit system as indicated below Final design circuit Indicator Circuits Indicator relays of heavy duty were found to be necessary for the operation of caravan flashers to avoid the standard unit from being overloaded or its flashing rate being affected in one way or the other. It was determined to be a requirement for the vehicles that are involved towing to be equipped with a tell-tale that is operational in both rear and front indicators. This is often described as C1 and C2 which represent the tell-tale for the car as well as an extension for the caravan function. The tell-tale in this particular project was set to be both audible and visible. The use of the mounted buzzer as well as panel light instrument was introduced to ensure a correct functioning of the indicator circuit system. Some circuit indicator systems operate through the alteration of the function of the standard flasher of a certain given warning signal in case of fault detection. This option refers to the extension failure monitoring system that that is responsible for checking built-in bulbs in a vehicle (Kamal, 2007). Tracing and correction of faults In the process of building the final design, the exercise that involved the tracing and correction of any exiting faults was carried out. This involved subjecting the final design to thorough evaluation with regard to its expected functionality as well as components. Three basic approaches were employed in this case and they included physical inspection of the circuit connection and its components. The second approach involved monitoring of the system’s operation to identify any performance or behaviour that was a deviation from the normal one. Thirdly, the designed circuit system was subjected to testing to determine it was able to perform as specified in the design objectives. There were several faults detected which included deviation from the expected performance in the operation of the circuit system. This was corrected through maintaining the design parameters. Evaluation An evaluation of the final circuit of the direction indicator system built involved examining and evaluating it against the desired design objectives and specifications. This was largely performed through a testing exercise where the final circuit was set to perform as was expected. Deviations from the expected objectives were then identified and noted as well as the improvements that would have been incorporated into the circuit system to improve its functionality. The final circuit was largely able to match the specified objectives. However, several points were noted with regard to things that went wrong in the entire design. This included lack of strict adherence to precision and accuracy in designing the circuit and its components as well as failure to follow the specified design procedure to the latter. The above shortcomings were noted as some of the ideas and improvements that would have enhanced the functionality of the design system. References Candela, T. (2009). Automotive wiring and electrical systems. North Branch, MN, CarTech. Grout, I. (2008). Digital systems design with FPGAs and CPLDs. Amsterdam, Elsevier / Newnes. Kamal, R. (2007). Microcontrollers: architecture, programming, interfacing and system design. Delhi, Pearson Education. Read More