SPEED GUN with MicroController

[theone_in_themoon]

I need to impelment a SpeedGun with a micro controller. My limitation is that i HAVE TO do it with a ATMEL 89 C 2051 controller.... because its my course project and needs us to do it by that very controller.

Plz guide me with ... the HARDWARE required.......links... ideas...and anyother advice that you think will be useful for me.

 

[Blackhawk]

What you do with your speed gun circuit will determine what you need to do with your microprocessor coding.

I made a projectile chronometer for my Senior Design project. I made two terminals which were 2 feet apart. (D) I used a comparator, and some IR diodes with IRsensing transistors to determine when the object was passing by each terminal. Basically an object was breaking two beams. I fed the pulses into my microprocessor and recorded the times of each. (T) Then since I knew 'D' and 'T' of the equation 'D = R*T' I just solved for R. If there are other circuits out there for speed detection then they may give a better solution for this problem. My method that I described above is kind of a 'dirty' method but it worked enough for me to get an 'A'. I am going to be watching this post to see what others think.

Good luck.

 

[techie]

If you are talking about a speed gun that measures the speed of a moving object using doppler effect then I am afraid it is not as easy as you think. It requires precise frequency shift measurement of RF signal.

Alternate method is to use image processing to determine motion and then analyzing the speed.

 

[chewbecca]

Try this link
**broken link removed**

The stand-alone Automobile Cruise Control is a microwave radar-guided, 68HC908QT4-based cruise control system for all types of vehicles. Using the Doppler effect, the system detects stationary and moving objects 50 to 75 m ahead or behind the vehicle.

--chewbecca