rotating disk

[athba]

hi

i hav Q about the sensor i want to calculate speed and direction of rotating disk colored by black and white,what type of sensor i have to use and how can i calculate the speed of the rotating disk and direction??

 

[mvs sarma]

If a Rotry encoder can be detected regarding is dirction, a rotating plate also can be.

the circuit assumes two sensors(reflective type ) which sensor is getting interrupted first decides the direction of rotation.
perhps you have to find the algorithm for rpm-- a possibility-- and no of interruptions per a known time can be counted and thre processor can calculate the rpm from a formula.

 

[ericgibbs]

hi,

>> i want to calculate speed and direction of rotating disk colored by black and white,what type of sensor i have to use
Use a reflective IR sensor pair module, TX and RX in one small plastic housing.
There are versions available that give a TTL level ouput.
[Black/White == Dark/Light == Low/High signal]

>> and how can i calculate the speed of the rotating disk
By knowing the distance from the centre of the disk to the point where the detector is located. Circ= 2 * pi * R. you can work out the linear speed.

For the rpm of the disk you count the Light/Dark transistions of the detector over a known time, say 60secs.

>> and direction??
The easiest way is you have a second IR detector pair 90deg [quadrature] from the first detector, from the two detectors you work out the direction.

A PIC would be my first choice for this application.

 

[gramo]

Have you programmed PICs before?

 

[athba]

hi
thanks alot for the help,but i do n't know anything about programming the pic Sorry

 

[athba]

could you please explain more about direction??

 

[athba]

plz i need answer.......

 

[mvs sarma]

plz i need answer.......

i think you shold mention the preson who replied for further clarification--there were three replies

 

[athba]

thanks for this note ,but i need the explaination from ericgibbs