How to measure the reference voltage Vref on the ESP8266-12e for the ADC?

Question

Hi,
I'd like to play around with the ADC in the ESP-12e and I have this little/big problem with the Vref. Theoretically the voltage is 1.0V, but how do I measure it to know exactly how much it is?
Playing with ADC in AVR, ATmega I could measure this voltage and substitute for further calculations, but here I have no idea how to do it ;(

Many thanks in advance for your help.

tmf · Accepted Answer

Apply a known voltage to the ADC, measure the value given by the converter and count how much the VRef actually is.

piotr411 · Accepted Answer

Maybe this link will do Link

tmf · Accepted Answer

I don't think there is a converter in the ESP with any exorbitant performance, and the stability of the reference source also leaves a lot to be desired. Perhaps the cause lies in the circuit itself and interference.

madejpm · Accepted Answer

Firstly, what are you actually measuring. Secondly remember that the ESP is the transmitter and the wires are the antennas, if you can then try to turn off the WiFi during the measurement, or take a few/some measurements one after the other and average the result. I only used the ADC to measure the supply voltage internally and had quite reasonable results.

piterek-23 · Answer

Thanks. All in all a good idea.
And I'm searching all over the internet to see if there's a point in the ESP on the PCB where you can measure it for yourself.

Added after 3 [hours] 24 [minutes]:

Gee, and can you give me a hint on how to convert this?
I have the whole circuit assembled, but it comes out something like this:
- on the ADC leg I have 0.31V
- ESP reading the ADC shows 329

The ADC in the ESP is 10 bits

Added after 29 [minutes]:

Will it be something like this?

Vref=Vin * 1024 / ADC

piterek-23 · Answer

Thanks gentlemen for your help.
Please tell me more why I get these readings when reading the ADC:

I have trimmed the readings to one decimal place because with two decimal places it is even worse. What does this depend on?

piterek-23 · Answer

Hmmm... ESP is certainly not a super design, but I thought it would be better.... My connection looks like this:

piterek-23 · Answer

I want to measure the voltage of a car battery.
With averaging the results I have already tried. By doing 1, 8 or 64 readings and taking an average from that, it doesn't change anything ;(

I will still try with turning off WiFi for the duration of the measurements.

piterek-23 · Answer

Electrode has asked to close the topic so I am closing

[Solved] How to measure the reference voltage Vref on the ESP8266-12e for the ADC?

Post #1

Post #2

Post #3

Post #4

Post #5

Post #6

Post #7

Post #8

Post #9

Post #10

Didn't find an answer? Ask Artificial Intelligence