IR reflectance sensor pendulum

Has anyone had any experience of using an IR reflectance sensor to measure the swing time of a pendulum?

If so could I have any suggestions such as suitable sensors etc, this is my first solo project and am In need of a little help to get started :stuck_out_tongue:


You might try this: Pololu Carrier with Sharp GP2Y0D810Z0F Digital Distance Sensor 10cm
Reflectance sensors can be slow (in the above case the response time is 3.8 ms maximum) so that limits the accuracy of your measurement. Beam break sensors (LED plus photodiode) are generally much faster.

Thanks for the reply, I should have mentioned the pendulum is a church bell so is probably too big for a beam break sensor, I was going to place a reflective strip on the bell wheel and time when IR light is first reflected off of this until it gets reflected at the end of a complete period. Rather than use the detection of the pendulum crossing the IR beam.

church bell so is probably too big for a beam break sensor

Unlikely. Garage door openers have beam break sensors as safety devices, and can easily detect a house cat or an automobile across a distance of several meters.

I should have probably been more clear, it'll only be doing small oscillations so won't clear the beam of a beam breaker if that makes sense.

tape a narrow stick on the bottom of the bell and place a photo interrupter so that the stick blocks it as it passes by.