Design And Development Of An Automatic Speed Limiter For City Minibus Taxi Using A Microcontroller-Based Electromagnet

Abstract

Ethiopia is experiencing an increase in road traffic accidents, much of which is caused due to human fault like over speeding. Among the frequent participants of road traffic accidents, minibus taxis cover the largest percentage. This study tried to make a speed limiter incorporating a strong electromagnet for restricting the driver by making the accelerator pedal stick to the magnet not to go further beyond the proper speed limit for minibus taxi. Selecting relevant materials for the system, writing the algorithm for the system, designing the circuit, preparing the electromagnet and making a prototype for its functionality are the main methods followed. Since most commercial vehicles in our country do not have a working speedometer, the designed speed limiter has its own speed measuring system using the effective wheel radius of a common minibus taxi. Arduino Mega microcontroller calculates the speed of the vehicle by measuring the period between two pulses from a hall sensor which is utilized to calculate the revolution per minute and velocity of a vehicle wheel. With this reference, the program compares the calculated speed with the nominated speed limit by a push button and activates an electromagnet by using a relay to act on the accelerator pedal of the vehicle. 30, 50 and 70 kmph are the three pre-set speed limits which were added to the limiter to effectively use the speed limiter inside the town zone. The designated speed limit is displayed on a 16X2 liquid crystal display. The display also shows whether speed limit is selected or not. When the driver does not select one of the pre-set speed limits which are mandatory, provided that the car is inside the town zone, a message is sent to the owner of the vehicle or other enforcing authorities. But even if the driver does not select one of the speed limits, the limiter selects 30 kmph as its default speed limit and speeds above 30 kmph is recorded in secure digital card with 1 second time interval. The electromagnet was simulated in solid work electromagnetic simulation software with varying the voltage. The simulation gave the values of magnetic flux density in different areas of the electromagnet. As the result indicated voltage value more than 36V gave a good fixing ability for the ferromagnetic material and a delay of 10 seconds is required in order to inform through a message.Ethiopia Is Experiencing An Increase In Road Traffic Accidents, Much Of Which Is Caused Due To Human Fault Like Over Speeding. Among The Frequent Participants Of Road Traffic Accidents, Minibus Taxis Cover The Largest Percentage. This Study Tried To Make A Speed Limiter Incorporating A Strong Electromagnet For Restricting The Driver By Making The Accelerator Pedal Stick To The Magnet Not To Go Further Beyond The Proper Speed Limit For Minibus Taxi. Selecting Relevant Materials For The System, Writing The Algorithm For The System, Designing The Circuit, Preparing The Electromagnet And Making A Prototype For Its Functionality Are The Main Methods Followed. Since Most Commercial Vehicles In Our Country Do Not Have A Working Speedometer, The Designed Speed Limiter Has Its Own Speed Measuring System Using The Effective Wheel Radius Of A Common Minibus Taxi. Arduino Mega Microcontroller Calculates The Speed Of The Vehicle By Measuring The Period Between Two Pulses From A Hall Sensor Which Is Utilized To Calculate The Revolution Per Minute And Velocity Of A Vehicle Wheel. With This Reference, The Program Compares The Calculated Speed With The Nominated Speed Limit By A Push Button And Activates An Electromagnet By Using A Relay To Act On The Accelerator Pedal Of The Vehicle. 30, 50 And 70Kmph Are The Three Pre-Set Speed Limits Which Were Added To The Limiter To Effectively Use The Speed Limiter Inside The Town Zone. The Designated Speed Limit Is Displayed On A 16x2 Liquid Crystal Display. The Display Also Shows Whether Speed Limit Is Selected Or Not. When The Driver Does Not Select One Of The Pre-Set Speed Limits Which Are Mandatory, Provided That The Car Is Inside The Town Zone, A Message Is Sent To The Owner Of The Vehicle Or Other Enforcing Authorities .But Even If The Driver Does Not Select One Of The Speed Limits, The Limiter Selects 30 Kmph As Its Default Speed Limit And Speeds Above 30 Kmph Is Recorded In Secure Digital Card With 1 Second Time Interval. The Electromagnet Was Simulated In Solid Work Electromagnetic Simulation Software With Varying The Voltage. The Simulation Gave The Values Of Magnetic Flux Density In Different Areas Of The Electromagnet. As The Result Indicated Voltage Value More Than 36v Gave A Good Fixing Ability For The Ferromagnetic Material And A Delay Of 10 Seconds Is Required In Order To Inform Through A Message.