Speed of ? Slotted Senser/Photo-Interrupter

Hello there,

Simple question about how fast a photo interrupter can perform:

The situtation (simple outline image also attached)

- photo interrupter positioned on a turning shaft (5 cm dia.)
- shaft profiled/formed so a disc profile shaft rotates inbetween the photo interrupter gap (3.2 or 2 mm)
- Disc form, has 5 holes in, equally spread apart by 72 d.
- Holes are approximatley 5mm diameter
- Shaft turns at 35 RPM

I've little experience of Photo Interrupter's and don't know if they operate fast enough at this RPM, or faster (max. RPM is 60). For example, maybe the disc hole passes the photo interrupter too fast to allow it to open/close the circuit?

Maybe this depends on the chip speed?

Maybe Photo Interrupters can operate with uSecond or pSecond speeds?

Appreciate anyones constructive help in advance.

rgds . john

Five holes at 60 rpm equals 300 pulses per minute or 5 pulses per second (200 mS between pulses*). That is plenty slow for phot-interrupters to work.

John

*Edit: For those concerned about detail, the time between pulses will be less, because the pulse has a width, but in any case, it is still not to fast.