Possible issue with Tab5 and UiFlow v2.3.1 - (i2c driver install error)
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So if I assume the ADC 12 bit option will give me 4,096 different points and the ADC 16 bit option will give me 65,536 different points maybe I can come up with a formula ( using the voltage - Pressure graph) of how to calculate Kpa when using ADC option for the Tube pressure... Everyone I am just thinking out loud so don't bash me too badly... LOL!
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what are RAW values you are getting from your sensor? pure analog read value?
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 Thanks for replying! With nothing connected to the Tube pressure sensor, I am getting a RAW value of 3,287 (12 bit option selected in the ADC parameter).
In regards to a 3.6V reference, where is that in the documentation?
I think we are getting close to solving this problem!
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@robski - I stumbled across this youtube video about an Arduino Pressure Sensor and was thinking about testing a version of his method for coming up with a calculation...
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with your raw value as 3287
sensor range -100 to 200
analog range 0 to 4095your calculated pressure should be around 140
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@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?
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@robski I keep coming up with 140Kpa also...
We must be missing something... -
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
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@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...
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This post is deleted! -
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) = 140.7KpaFor 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 -
@robski I sent an email to M5Stack Support about the possible issue with the Tab5 and Tube Pressure sensor BUT no response so far....
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@Kenzo
This is an ADC problem. We are fixing UiFlow2 codes. Please be patient. -
@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.
