I am wanting to use the ADC on the nodemcu 1.0 but it's not

I am wanting to use the ADC on the nodemcu 1.0 but it’s not clear what the maximum voltage should be, some docs suggest 1.0v others 3.3v.


Feed him 1V and measure?

I have a chinese clone and it’s 3.3 volt. But I think the adc isn’t high quality, when feeding 3.3v I get a value around 950 (out of 1023).

On a Nodemcu there is a voltage-divider on the PCB for 3.3V -> 1V connected to the pin, so you can use a 3.3V maximum on it. That said, I agree with @chris_cauwelier in that the pin is horribly noisy: it’s okay if you just need some rough indication, but you still need to calibrate your code for your module. If you need something that isn’t as noisy then you should use an external ADC.

Indeed noisy, when taking averages of 100 samples from an attached ldr, the results show still ‘spikes’ in de serial plotter. CTRL+SHFT+L on arduino ide.

I have 4 different Nodemcu-boards and on none of them the ADC actually gives out 0 when connected to GND. Even worse, each and every one of them give a different value when the ADC is connected to GND o_o

Thanks everyone, explains why I see the 2 voltages quoted, sounds like the ADC is the only letdown on these boards

I’ve used several wroom02’s without issue. I gain my mic for 0 to 1 volt and can read 0 to 1023. I’m trying to encode WAV so I can stream out the mic audio.

it’s supposed to be from 0 to 1.0 V.

@Rtzz0 ​ No, it’s not. The 0v-1v range is for plain esp8266, but the Nodemcu has a voltage divider on the pin to get 0v-3.3v range.

@Nita_Vesa Sorry, I missed the nodemcu part. I need to go to sleep haha

@Nita_Vesa I found the schematic for the Nodemcu and it has a 220k/100k divider