Analog pressure sensor on either D1 or D1Mini

Other Hardware Sensors
1

Hi all,
I purchased 2 of the followed Analog pressure sensors, need to measure a 2-3M column of water.
Please assist. I usually play with RPi's (with Python), but they don't natively have analog capabilities.
This (D1 platform and how it is programmed/imaged) is foreign to me so hoping someone can assist.

I am able to physical measure the water depth at say full, and then associate that voltage with a 100% value ... and say reduce the level some, measure again,

I have a D1 and D1 Mini. would eventually connect both sensors onto one board.
Output preferably via mqtt

G

2

One meter column of water is .01Mpa, says Pascal.
https://www.grc.nasa.gov/www/k-12/WindTunnel/Activities/Pascals_principle.html

The red wire is 5vdc. The yellow wire should give readings inside 5vdc-0vdc like this:

Vout = VCC x (0.75 x P + 0.1) // P is Pressure
3

It will not work they way you think. Read line 3 in the spec, it states: " * Output Voltage(Vout): DC 0.5~4.5V" not 5-5. That will make a big difference. To get 0-5 you need to precondition the signal possibly with an op amp circuit.

4

That sensor is a 5volt-logic ratiometric sensor, and won't work very well with a 3.3volt D1 mini.
Get a sensor with an I2C interface. Then you can use it with any processor, including the Pi.

Match the sensor rating to the pressure you're measuring (about 25kPa in your case).
If you don't, then you will have a poor resolution.

These 40kPa sensors could be nice to play with. They use a HX710B chip (not I2C),
which you can find a library for on the Arduino site.
Leo..

1 Like
5

In addition to the above comments, I think you will be disappointed with the results.

3 meters of water is approx 21kPa. Your sensor is 1200 kPa. You would be using < 2% or your range.

Pressure sensors in general tend to have a zero value drift. Your sensor being ~$12 is going to easily have a 1% drift over time (fairly short time).

So unfortunately, this sensor is pretty much useless for your application.

2 Likes
7

Just asking... don't shoot...
hmmm so the sensor want (input) 5V... can I not use a buck converter to step up the voltage ?
re get I2C
... ye all way down here in SA thats easier said (to get) than done...

G

8

... found my problem, I originally added 1 bar to my water of .2 potential to end at 1.2bar... out of a potential range of 12bar... so was thinking, not perfect but it's at the 10% range.

Agree a "smaller designed range" would be better.

... trying to cancel the order.

G

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