Recording number of dig input state changes with Arduino

[A123J]

Hello, looking to connect a rotary encoder (TTL output) directly to arduino, monitoring one channel.

As motor turns 360 degrees, the state changes for one channel will be 1-0-0, or essentially 1 state change per turn.

How can i record how many state changes have been completed? Does anyone have any sample code i can use?

for example if i want to rotate the motor 50 turns, i will enable the motor, and after 50 turns, another digital output will be triggered which will communicate to a servo controller to STOP the motor.

Thanks
A

 

[DrG]

To me, what you are describing is a tachometer. There are many tutorials on using a magnet and a hall effect sensor to accomplish such a task. Here is one.
Searching will produce many more.

If you really want to use a rotary encoder like this one, there are also many such tutorials. Here is one.