ESP 32 ADC problem

hello @carro007 !

After reading your post, I found these links: https://docs.espressif.com/projects/esp-idf/en/release-v4.4/esp32/api-reference/peripherals/adc.html

https://deepbluembedded.com/esp32-adc-tutorial-read-analog-voltage-arduino/

regarding your question about ESP32 ADC problems.. check this out and let us know if this takes care of your problem..

regards,

LouisR

@carro007 Look at the date

Thanks LouisR, yes, I tried those "tricks" mentioned in the Minimizing Noise section but not enough improvement there. However, I only had "slower" electrolyte capacitors available but the results did not convince me to go further on that path. I think I read some time ago that improvement is expected at some point in newer ESP32s. Maybe they are already available on the market if one knows what to ask for. The market is still full of these older designs I bought from Ebay. 

Ron yes, a year is a long time but I can tell you they seem to pass so quickly for us seniors.

Hi @carro007,

  There are a number of ESP-32-xx variations, where xx can be something like C2 or S3, etc, most, if not all being more recent than the 'plain' ESP32... a quick scan around Ali-Express will list them.

However, I recall reading a review of them recently, and whilst some of them are definitely upgrades in some respects (others are cheaper variations, etc.), a moan in the review is that the ADC capabilities had not been significantly improved, in spite of the ESP32 having a reputation for being relatively poor.

I emphasise that this was only one review, which might well have had more than its fair share of fake news and ignorance, but it was not an encouraging sign. Other reviews have also said the ESP32's ADC is poor, but this was the first one I recall discussing the newer models. I think if Espressif had markedly improved the ADC, they would be advertising it clearly and brightly.

It is worth keeping a look out for improvements in the future, but for now it appears a separate ADC is a good direction to take, if you want to use any of the ESP32 family to make reasonably precise voltage measurements. (For applications only needing (say) about 8-bit resolution, maybe the ESP32 would be ok? )

Best wishes,

Dave

All right, thanks Dave. Just for fun I may try to find one of those later versions you mention despite the discouraging reviews there may be. Good ADC tech has existed for who knows how long so it is amazing if they can't/won't copy it on Espressif SoCs at some point. Otherwise the chip is pretty handy in so many respects not to mention price tag. 

Regards,

Carro

Hi @carro007,

   Good luck with your research .. if you are successful, that will be interesting news!

Best wishes, Dave

@carro007 Wait until you are my age, 81.

@carro007 Have you checked out the PICO, can't beat the price either.

Hey guys, I have just seen that this thread suddenly became active and I am surprised to see that I forgot to add update on my issue. 

So basically as the ADC on the ESP32 is not working properly we switched to ESP8266 as our application doesn't need all the peripherals that ESP32 will offer. So as we need more ADC pins we had used an external ADC module which is ADS1115 a 16-Bit ADC- 4 Channel with Programmable Gain Amplifier, which talks with ESP8266 via I2C. 

Sorry for the late update.

Regards ,
Sai

Ron, I'll catch you soon 😉

No, I haven't tried Pico yet. You are right that might be a solution if it has ADC and can send HTTP POST messages. Thanks, I must look into it.

Hello Sai, yes, that's the way I planned to go too and have ordered a couple of ADS1115. However, I did not know about the Pico possibilities, that might be an even better choice with only one unit, must look into it.

Rgs,

Carro

@carro007