I've been assuming you have checked that pin 22 is not one of the four pins set up in your I²S pin configuration.

I am not using I²S. I'm taking .wav files from ESP32 flash memory, or from the internet via WiFi, and outputting mono audio from one of ESP32's digital-to-analogue converters. Anyway, checking on an oscilloscope, I am not getting any data or clock signal on the D22 pin. However, I've recently had th...

Hi Andy,

Sorry, I've not been able to find what's driving pin 22.

If you completely disconnect the relay board, do you still get that same 1.4V to 1.8V on the ESP32 development board output pin? If so, that proves the issue is nothing to do with the relay board. You seem to have data on that pin during setup and during I²S audio. Have you considered controlling th...

I understand the visible LED is in series with the LED within the optocoupler and a 470Ω resistor. The three items are connected between the +5V supply of the relay board and the input connection to the relay board. So if the visible LED is dimming, either the 5V supply is reducing or the input from...

I have been under the impression from forum posts that the maximum GPIO output current from an ESP32 is 12mA whereas your relay board requires 15 to 20mA. That's partly why I have been suggesting the need to have a buffer capable of supplying up to 20mA. However, I have just checked the datasheet of...

Yes, the octal buffer needs a 5V supply. I would expect you to use the same supply that you use for your relay board. I would be very apprehensive about using USB power. If you are using an ESP32 development board that requires a 5V supply, I would recommend using the same supply. When using separat...

According to information from Amazon and directly from Elegoo, each channel requires 15 to 20mA drive current. It is not clear whether that is for input low or high, but probably low. The data you link to regarding the relay is irrelevant because there is evidently an 817C optocoupler for each input...

all I get is noise on the speaker that is connected to the Adafruit amp. For I²S your data needs to be signed in two's complement form. If not you will get extreme distortion that sounds rather like noise. (If you use one of the ESP32's digital-to-analogue converters, the data needs to be unsigned.)

Using I²S should give you really good sound quality so it's probably well worth trying to get it to work. If you find you can't make progress, I suggest you use one of the digital-to-analogue converter (DAC) outputs of the ESP32. For speech messages, I am using 8-bit samples at 8kHz stored in ESP32 ...