Where can I buy a Digital Revolution (spin) Meter for like a motor?

[ACvolts]

Ah, don't know where to find one!  Or the right words to do a search. 

[Jon Chandler]

You might look at tachometers.....

[ACvolts]

Yeah I found a bunch of cheap ones and expensive ones on Amazon, thanks.

2 in 1 Digital Laser Photo Contact Tachometer DT2236B
http://www.amazon.com/Digital-Laser-Contact-Tachometer-DT2236B/dp/B00CCZLSQ6/ref=sr_1_2?s=hi&ie=UTF8&qid=1373840686&sr=1-2

-or-

http://www.amazon.com/BestDealUSA-DT2236B-Digital-Contact-Tachometer/dp/B009DARQ0A/ref=pd_sim_sbs_hi_2


Neiko 20713A Professional Digital Laser Photo Non-Contact Tachometer with Accuracy 99,999 RPM Measurement
http://www.amazon.com/Neiko-20713A-Professional-Non-Contact-Measurement/dp/B000I5LDVC/ref=sr_1_66?s=hi&ie=UTF8&qid=1373837321&sr=1-66

[mariush]

You mean something like this :

http://www.digikey.com/product-detail/en/EMS22D51-B28-LS5/EMS22D51-B28-LS5-ND/3694109

?