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### Topic: Hygrosens Doppler effect sensor for velocity measurment (Read 1 time)previous topic - next topic

##### Jan 23, 2012, 11:52 pmLast Edit: Jan 25, 2012, 06:38 pm by Aduen Reason: 1
Most of the topics I found (dating before 2011) about this one sensor start of like this:

Hey, I have this sensor from Hygrosens:

Does anyone have any experience with this module...

So hereby.

I have it hooked up to the arduino (nothing to difficult), open-collector works fine with an interrupt.

I've also did some arduino-oscilloscoping and found that the line-in of the pot gives out some more data if used raw in an analog pin (did some multimetering to, all neatly within arduino capabilities). It gives a frequency and a voltage. The frequency should provide some velocity measurment and the voltage the amount of waves returned (e.g. size of object). None what so-ever documented in exact details (Hygrosens is enquired).

I've tried sampling the analog pin with pulseIn() but got the same result every sample. I would agree that it means I should only have to sample one time but, I'd like to know if anyone else tried hooking it up like this...

I've also not tested the velocity yet, "whacking" at it didn't deliver anything beyond 23Km/h (wouldnt know if thats correct  :~ ). Knowing
Quote
"...signal originating at the mixer output is proportional to the speed: 44 Hz corresponding to a movement speed of approx. 1 km/h."

With no more interesting code:

Code: [Select]
`//lowest F 5Hzunsigned long f = pulseIn(A0, HIGH, 200000);//44Hz == 1Km/hf = (1000000/f);float kmh = f/44.0;`

If I find a way of more precisly measuring the outcomes, I will let it know in this thread. For now, anyone, experiences...?

#### robtillaart

#1
##### Jan 25, 2012, 10:33 pm
(no experience with this sensor, but it sounds interesting)

Quote
If I find a way of more precisly measuring the outcomes

You could drive in a car and measure the raw data (scope?) and create a lookup table?

wrt code:
- PulseIn() is meant for digital signals not for analog ones, that will introduce trouble I expect.

Can you post a picture of the signal on the scope?

Can you post your complete sketch? minimal version?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

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