[PD] [OT] Using a webcam to measure a wheel's rotation speed

Matteo Sisti Sette matteosistisette at gmail.com
Thu Sep 2 17:54:10 CEST 2010


Hi,

I need to measure the rotation speed of a spoked wheel.

As an alternative to a suitable sensor + arduino, I was considering 
using a webcam placed very close to the wheel and counting the frequency 
at which the spokes pass in front of the webcam.

Has any of you tried anything similar? Do you have any suggestions?


My naïf idea is that if a (natural or artificial) source of light is 
placed in front of the webcam, when the spoke passes in front of it, it 
will reduce considerably the brightness of the whole frame or of a big 
portion of it.

I'm looking for something simple: if this eventually leads to a 
complicated artificial vision task, or if a good calibration is 
difficult to achieve, then I would rather go for a tachometer and an 
arduino...


Thanks in advance
m.



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