Getting Feedback on Flow Sensor

[Ryan S]

I'm trying to use a flow sensor to get PWM feedback to be received by a microcontroller. To test the sensor, I've wired the following to get feedback on an oscilloscope so I can get a feel for how the frequency adjusts based on the flow rate.


When I wire the flow sensor (the other grey sphere is a temperature which I haven't started on yet), the oscilloscope does not change voltage or frequency (solid line at 7V) when I have water flow through it. I've adjusted this circuit so that the resistor is in different places (I'm new to this thing so I figured I was doing something wrong) but at this point I'm not sure what I'm doing wrong. Is there some glaring problem I've overlooked or is this part just possibly broken?

 

[Alec_t]

Welcome to EP!
You don't have a ground connection going anywhere useful.
What is the flow sensor spec? Datasheet?

 

[Minder]

The link to the sensor does not show any electrical specs?
M.

 

[kellys_eye]

Suggest one lead of the flow meter goes to ground, the other (signal) lead goes to 12V via a resistor and you take the measurement signal from the resistor leg connected to the transducer.

It's only a two-wire sensor and one must be ground. The only other way to get power and a signal is via a 'load' (the resistor) connected to the supply line.

Note - mis-connection MAY have irreparably damaged the sender.....

 

[Ryan S]

Suggest one lead of the flow meter goes to ground, the other (signal) lead goes to 12V via a resistor and you take the measurement signal from the resistor leg connected to the transducer.

It's only a two-wire sensor and one must be ground. The only other way to get power and a signal is via a 'load' (the resistor) connected to the supply line.

Note - mis-connection MAY have irreparably damaged the sender.....

You are amazing! A replacement part finally came in and I was able to get it working off of your recommendation!!!

Was definitely a difficult challenge given that the company didn't provide any datasheets and weren't willing to help me figure this out... thanks to all that helped out