Hello everybody,
does anyone know if there is any way to read approximately 40/50 mV with the ESP32?
Thanks in advance!!
Do you just want to know if it's greater than or less than 40-50mV?
Is it just a plain ESP32 and not one of the S or C versions like ESP32-S2?
It's a simple ESP32
The lowest volatge you can accurately measure with the ESP32 is 100mV.
https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html#analogsetattenuation
You need to use a sensor ship, such as a load cell amplifier or a current sensor, which will actually be measuring a tiny voltage without a shunt resistor. It has mV sensitivity. Checkout the HX711 load cell or the ACS712 boards. Also an operational amplifier will do the job. But the easiest will be the HX711. It has two inputs and measures the difference between the two in mV.
50mV is not within the common mode input voltage range, so it will not work.
Can he bring what he is sensing into the common mode range?
Or are you saying the HX711 is too sensitive for 50 mV?
Why ask me? Ask him.
Or are you saying the HX711 is too sensitive for 50 mV?
Sensitivity and common mode range are two completely different things.
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yes there are many ways.
Which is appropriate to your application we wont know unless you tell us WHY you want to do this. And the precision and accuracy you are seeking.
THE ESP32 ADC is a heap of XXXX
not the best.
An external adc might be your best option.
Yes, but you mentioned 50 mV, and that was confusing. You seem to imply that if it were a different voltage, it would fall in the common mode range which is not correct.
So how do you know the HX711 will not work, if you don't know what the common mode is for the input?
Why is it confusing. It's what @student_897 wants to measure.
Maybe you should read the entire post before replying.
if you don't know what the common mode is for the input?
I do know. If you read the datasheet you will also know.
So you know what the common mode voltage is for the input? What is it?
You are confusing the common mode of the HX711 with that of the input. I speak of input while you speak of HX711.
This is what you wrote. You imply that he is not within the common mode range of the HX711 because it is 50 mV. What makes you think that the input common mode is out of range? Nowhere does he say that what it is in the post.
So can you explain that?
I can amplify the signal. But let's say that I didn't realize that a simple ESP32 could not measure such low voltage values.
With my question and by precising "50 mV" I specified the lowest amplitude I needed to measure from my system. I can have many intermediate values and the maximum value can be approximately 2V.
I don't need an extremely high accuracy and precision because then I will calibrate the system.
The lowest voltage is still 100mV no matter what you do.
Ok perfect, thank you very much!
Your are welcome!
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