Hopefully M5Stack Team is getting close to resolving the issue... I was planning to use the Tab5 project I was working on for the M5stack Innovation contest but it looks like that will not happen due to the issues I am running into with finding an air tube sensor that will accurately work with the Tab5... Oh well... Hopefully the M5stack team will release an upgraded Air Tube sensor soon that will easily work with the Tab5... Until then, I will keep searching for a solution....

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...

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

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

your calculated pressure should be around 140

https://youtu.be/UrqPxwsPWGk?si=4Ho9CQwpoFZstMBk&t=321

In regards to a 3.6V reference, where is that in the documentation?

I think we are getting close to solving this problem!

try below

float raw = analogRead(sensorPin); // Read analog value
float Vout = raw / 4095.0 * 3.6; // Convert to voltage (assuming 3.6V reference)
float P = (Vout - 0.1) / 3.0 * 300.0 - 100.0; // Calculate pressure in kPa

@robski - I went back to my Tube example and the only one that worked was the ADC parameter to pull data. (I used 12bit)

So I looked at the UiFlow1 example for the Tube Pressure and tried to duplicate it. The program now runs BUT I am not sure if I am using the correct math conversion to convert the raw data from the ADC parameter into Kpa. I have searched a couple of sources BUT can't seem to find documentation that fully explains how to correctly calculate Kpa with the ADC parameter to Kpa...

Does anyone know were to get really good documentation on the tube pressure sensor that explains how to properly calculate Kpa using the sensor with ADC option?

I think that is what I wanted to tell you guys with my previous post. The i2c driver install error, which I also get, does not prevent most of my units to work properly.

Out of all my units only two did not work and two I2C units would only work after switching the i2c speed to 400 k.

In other words I do not think the i2c driver install error matters in regard with the Tube Pressure unit, which is not an I2C unit.

@Kenzo : do you have any other units you could try with your M5Tab5? Or any other core(s) you could try the Tube Pressure unit with?

Thanks
Felix

Question: Could this be a possible bug somewhere when it comes to Tab5 and the UiFlow IDE???