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Topic: Ultrasonic Anemometer (Read 32 times) previous topic - next topic


Hi Carl,
im having some problems here, i would like to know how do you get Zero Crossing Detecting... Here, if I do this I get a Square Wave all the time because of the noise, that keeps crossing zero. How do you detect that the zero crossing isnt a noise? Do you have any graphic that shows the reception wave + the zero crossing at the same time? 
Thank You.


Have you downloaded the projectreport.pdf.

The circuit is shown there and R22 is used as a threshold set.
Adjust this value to give output only when signal is received.

A CRO picture of the ZCD output is labelled "Output from the zero crossing detector with example program CRO".


Sorry for posting here, but when I went to your main thread, I couldn't get to or find the REPLY button.

Oh well.

Hey, great job.

How much would it cost to build one?



Sep 21, 2012, 03:52 am Last Edit: Sep 21, 2012, 03:59 am by carl47 Reason: 1
on a bread board the parts cost me about AUD $60

I will not answer any more questions until 1-11-2012

I will be on holidays, including catching a train from KL to bangkok and I will not check my sites or mail.



I'm currently laying up the digital part of the circuit in Eagle with an Arduino Nano as the plugin CPU. I'll then move onto the analog part, starting with the existing circuit but I expect to move to an all op-amp solution pretty quickly.

I may integrate the wind speed measuring stuff into my BeRTOS Arduino branch https://github.com/g8ecj/bertos stuff as I then get an LCD display "for free" :)

Got a few wrinkles in my wind turbine project to test out in the meantime so I may be a couple of weeks before I get to etch some copper!!
Robin Down Under (or are you Up Over!)

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