Communicating with ESP32 microcontroller to phone via USB cable

zazas321 said:

Hello. In my project, I need to have a wired connection between the phone and the ESP32 microcontroller.

I would like to achieve the same results as if I connect the ESP32 to the PC. When the ESP32 is connected to the PC via the USB, it is recognised as a COM PORT and I can send serial data to my microcontoller via the Terminal and communicate with it without any problems.

On my phone, I have downloaded the following APP : https://play.google.com/store/apps/details?id=de.kai_morich.serial_usb_terminal&hl=en&gl=US

I have connected one end of cable to my phone and the other end of the cable to the ESP32. I have powered up the ESP32 via the external 3.3V. Unfortunately, on the APP, the serial device is not detected.


I would like to know what could be wrong and how to properly do it. Is this possible that both my phone and ESP32 is acting as slave and hence it will not work? How to fix this issue if that is the case?

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I just love how everyone above has totally overlooked the problem. The ESP8266/ESP32 products do not need special hardware/software to speak serially (use the serial prints in Arduino or print() in MicroPython). In the old days, device 1 says "I speak Serially", device 2 says "Me too, lets talk!" Now a days its a little more complicated (PC and USB OTG are similar in this): device 1 "I speak Serially", device 2 "Me too!", device 1 "oh yeah, what's your chip?", device 2 answers, device 1 "well, I don't support that chip (no drivers/not built in)." And that's the problem with the USB Serial terminal apps on the phones - they support the CH3xx family (ESP8266) but not the ones on the various ESP32 devices. I recently experienced this when I switch from the ESP8266 to ESP32, first question from the Android's USB Serial Terminal app was for the other device's chip and the ESP32's USB to Serial chip wasn't listed. Until the apps are updated, you will have to use wifi and/or bluetooth or else add other physical modules and needed software. I don't know the state of the iOS apps but would guess they are in similar status.