Thanks Ashutosh for your response. After doing some research, I am selecting this approach, to calculate the speed of bicycle in kph
Measure the wheel diameter and then multiplying it PI to get circumference of wheel. This distance is the distance travel by one revolution of the wheel.
If suppose, I am having 30 spokes on my bicycle then setting a counter to 30 in attach interrupt function. If it matched then time is captured and indicating the time travel for one revolution.
Now, with these two measurement I will obtained speed in (m/s) which will be then converted into kph by conversion formula. I hope I am in right direction now. Once again thanks.