MPS20N0040D-D sensor not working properly

Thread Starter

awwsome

Joined Mar 10, 2018
3
I am using MPS20N0040D-D sensor for drowning detection application by attaching a pipe on the nozzle of the sensor. The other end of pipe is submerged in the water. Theoretically, the value of the reading should change as we submerge the pipe in water, but it remains constant value at 148 ( I am using 10 bit adc) . I am using the following circuit for the differential amplification of the data.



This is the image of the sensor



I am using a ATmega32a for ADC purposes. Is there any way in which we can check if the sensor is working or not.

Please help ASAP. Thank you in advance.
 

Raymond Genovese

Joined Mar 5, 2016
1,653
Did you try the simple test that is described from the site that the schematic you posted comes from?

Granted, he had some initial problems, but attaching a plastic tube and blowing seems like a reasonable test to see if anything is working. Calibration? No, but a simple test, yes, I would think.

From: http://langster1980.blogspot.com/2014/11/how-to-use-pressure-sensor-with.html

"Once I had uploaded this to the arduino and opened a serial monitor I expected there to be a steady stream of values being output to the serial monitor - there was! Excellent. I then attached a small piece of tubing to the pressure sensor and blew down the tube (provided some pressure)....Nothing happened....I then checked all of my connections and swapped the LM358 OP-Amp for another one....just in case and nothing happened. I then removed all of the connections and rebuilt the entire circuit and reconnected it to the arduino and repeated the test and nothing happened. At this point I was beginning to think the sensor was faulty....I'll be honest - I then gave up and moved on to other things.

I later revisited the circuit and re-tested it once I had it connected up on the breadboard. It now does work and displays both positive and negative pressure. The sensor's resolution isn't great but it does work. I don't have a calibrated pressure source so I can't prove the output is correct. The connections are as drawn above. Here is the diagram of the connections (It's probably easier to follow...)"
 
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