Hey. Has anyone here had any experience with the dip-6 MPS20N0040D-D pressure sensor?
I know they make and sell a pressure sensor module that are designed for arduino and has a clock and data pin. But i'm attempting to make one from scratch. I have the pressure sensor itself and a lm358 op amp. I have found multiple, but similar diagrams on how to wire it, but i'm having problems i can't understand.
Each resistor in the sensor in the sensor is about 4.7k ohms. But here's the problem. Below is pic from the datasheet. pin 4 is not supposed to be connected to anything.... but that's not the case. For some reason, pin 4 is actually pin 3 in the diagram, and pin 3 is not connected to anything. So it's like the datasheet is backwards, or they are looking from it's belly instead of the top, which is incorrect but doesn't make any since
pin 1 to 2 is 4.7k ohms........ normal
pin 1 to 3 should be 9.8k ohms, but is nothing
pin 1 to 4 is 9.8k ohms, and should be nothing
pin 2 to 5 is 9.8k ohms.... normal
pin 1 to 5 is 14.3k ohms..... normal
pin 1 to 6 is 19k ohms.... normal.
and pin 3 to any other pin..... nothing.
One way i tried to wire it, it did work to a small degree, but the resolution was very small... like a 10 point difference between no pressure and a couple pounds, So something isn't correct. i've used small pressure sensors in the past and they were sensor and op amp together. But because of covid, the sensors i've used and liked jumped in price from 10$ a piece to over 50$ thanks to all the ventilators they built. so i had to resort to build from scratch. but i'm having issues getting anything to work.
in the pictures it shows what to do to hook it up to an arduino.
I have since messed with some of the resistors on the op amp and got a little more resolution. But it's not as sensitive as it needs it to be yet. but i'm still messing with it.
I'm trying to avoid using breakout or unattached boards. I've already built a working prototype of my project out of modules, but now i'm consolidating everything onto one board, and plan on ditching all modules and eventually the arduino and replacing it with the atmega-328 chip itself.
most of the pressure sensor modules sold use the sensor that i have, but they use the HX710B chip, which is similar to the HX711. But all of the HX710B chips are in china so it will take me a couple weeks to receive them, which i'll probably end up going that route in the future. I just got spoiled with the couple sensors i have which are just plug and read from arduino.
My project doesn't call for precise pressures, but i do need it to duplicate user set pressure from 0 to 5psi. At the moment i'm looking at all of my options and seeing what i need to do. I found another pressure sensor that i can use that is similar to the MPX5050GP sensor that i'm using now, and they are only 15$ a piece. But they are discontinued and eventually will be out of stock and then i'll have to make other arrangements...... which is why i'm trying to put something together with currently available components.
It looks like i'm going to have a couple weeks to play around with the op amp to see if i can get a usable version.
Note that the HX710 doesn't have the excitation voltage regulator that the HX711 has.
You must provide that externally, or accept some instability.
If you want to make your own design, then you could buy boards with the sensor and HX710.
Removing sensor and chip is just a matter of laying them on a (220 degrees C) hotplate, and picking off the parts after a minute or so with tweezers.
Leo..
