Comments on: ESP32 ADC – Read Analog Values with Arduino IDE

By: Martin

Martin — Sat, 08 Feb 2025 19:19:51 +0000

In reply to Mark Kelly. Are you using a LIN or LOG potentiometer?

By: lettcco

lettcco — Tue, 26 Nov 2024 22:34:27 +0000

Can you comment on analogReadMilliVolts() vs analogRead()? I am interested in using the former, knowing that max V is 2.865 but is a lot more precise. Thanks!

By: We

We — Sun, 17 Nov 2024 02:49:49 +0000

In reply to Chris. Other comments above convey this same information. When the esp32 looks at an analog input, if attenuation is set to 0dB, then it maps the values 0-4095 to voltages 0-1100 mV. I’ve seen that the default is 0dB. To change the behavior of the esp32 one must change the attenuation. To get full range 0-4095 mapped to 0-3300 mV the attenuation should be 11 dB. By changing attenuation, I think the esp32 routes the signal through internal voltage divider resistors before reading its value.

By: Martin Jakobsen

Martin Jakobsen — Tue, 29 Oct 2024 06:54:55 +0000

In reply to John. Have you tried turning off the WiFi/Bluetooth radio while sampling?

By: John

John — Mon, 28 Oct 2024 03:26:01 +0000

I am getting huge noise problems with the A/D inputs on the Wroom ESP32 revc part. I have a 10K pot, connected to gnd and 3.3v pins. wiper is connected to A6 (34), although it doesn’t seem to matter which port I use. If I run in a loop sampling the port everything seems to work properly, but if I don’t touch the pot knob, my readings are all over the place.. usually within 15-20 but sometimes jumps of over 200. I’ve put .1uF cap on analog pin, tried filter cap on 3.3v supply, fiddled with attenuation, makes no difference. Same configuration on Uno is rock solid. This happens with all three processors I tried. Any ideas?

By: Paul Cas

Paul Cas — Fri, 04 Oct 2024 18:55:08 +0000

I am trying to set up more then 4 Pot meters to the ADC Channels.

I keep getting cross talk and interference between all of the different potentiometers. Can you do a guide for dealing with this?

I know i have a problem with capacitors but this would be helpful!

By: Marcos

Marcos — Wed, 24 Apr 2024 13:56:40 +0000

In reply to Blackneron. Thank you! I will do your steps yet but I was wondering why when I receive 1.72V it interprets as 1.51V, and 370mV as 290mV, when all the inputs were tested in laboratory before...

By: Hamza

Hamza — Sun, 24 Mar 2024 01:05:20 +0000

In reply to Alex L Chalmers. How did you achieved this sampling rate ?

By: sandeep kumar

sandeep kumar — Wed, 29 Nov 2023 03:01:30 +0000

In reply to Futterama. yes these are quite useful but i could not find them in arduino 2.0.1. is there a workaround?

By: Anwaar

Anwaar — Sat, 19 Aug 2023 06:31:32 +0000

In reply to zygfryd. Use very low dropout voltage regulator to provide stable 3.3V (Like MIC5219). That'll keep providing the ESP with 3.3V even when there's 4.2V in battery upto voltage drops below 3.3V.