Find object speed (Velocity Km/H) Using single Ultrasonic Sensor ((HC sr04)

i am some what weak in arduino programming :cold_sweat: . It's my class assignment given by my staff , he just simply given me a arduino and one ultra sonic sensor (HC sr04) and he told me to find the object speed which is CROSSING through the sensor's path ..he(staff) said that it is possible to find the speed using one sensor itself .. what i all need is object speed in (km/h) ,and coding for this task ..I'm sorry to force you , but i need as soon as possible...i am extremely sorry for my poor english =( :~

If you know the length of the object, and it is quite slow-moving, this should be possible, but bear in mind that you may be only able to perform around 20 measurements per second, so there may be a large margin of error.

If you want code written, I can move this to "Gigs and collaborations" for you.

thanks for your replay , the object crossing through my sensor is small in length and some what slow moving only …all i need is coding for that program …so please try to help me bro…

"small" might be a rowing-boat in comparison to a cruise-liner. "slow" might be a ...rowing-boat in comparison to a cruise-liner. You need to hang numbers on these concepts.

all i need is coding for that program

What have you got so far?