Possible issue with Tab5 and UiFlow v2.3.1 - (i2c driver install error)

robski

with your raw value as 3287
sensor range -100 to 200
analog range 0 to 4095

your calculated pressure should be around 140

Kenzo

@robski - hmmm.... Well that raw value was with nothing connected to the Tube Pressor sensor. Because nothing is connected to the tube pressure sensor I would assume it would be closer to 0 Kpa... 140Kpa is a big difference from 0 Kpa... I wonder what we are missing?

Kenzo

@robski I keep coming up with 140Kpa also...
We must be missing something...

robski

just connect voltage to sensor and measure what voltage it is giving out between output pin and ground. for 0 kPa your raw Analog value should be around 1300 i think

Kenzo

@robski - I think you hit on something there! I measured the voltage between the ground and the sensor and it came to around 1.1v which according to the graph should be around 0 Kpa. (see attached photos) Something is definitely strange...

Kenzo

This post is deleted!

Kenzo

Also here is the formula I was using to calculate Kpa

So for 12 bit parameter, this gives a kpa resolution of 300Kpa/4096 bits or 0.0732421875 kpa/bit (73.2pa/bit)

x = ( (0.0732421875 kpa/bit * Raw Value bit) - 100Kpa)
x = ( (0.0732421875 kpa/bit * 3287 bit) - 100Kpa) = 140.7Kpa

For the 16 bit parameter this gives a kpa resolution of 300Kpa/65536 bits or 0.00457763671875 kpa/bit (4.6pa/bit)

x = ( (0.00457763671875 kpa/bit * Raw Value bit) - 100Kpa)
x = ( (0.00457763671875 kpa/bit * 52600 bit) - 100Kpa) = 140.8Kpa

Kenzo

@robski I sent an email to M5Stack Support about the possible issue with the Tab5 and Tube Pressure sensor BUT no response so far....

kuriko

@Kenzo
This is an ADC problem. We are fixing UiFlow2 codes. Please be patient.

Kenzo

@kuriko Thanks Kuriko for responding and taking a further look into the issue! Looking forward to testing out the updated version of UiFlow with the fix!

I will now wait quietly and patiently while your team works on an ADC fix.

Kenzo

@kuriko Just finished testing the latest release of UiFlow (v2.3.2 ).

The Kpa readings was better this time but the accuracy is not there yet... See attached photo.

Hopefully the next release will improve the accuracy of the Tube/Air sensor and Tab5...