ESP32 Dev Board Micro-SD issue

Learning kit for Arduino
1

The demo code to read and write a test file to the SD card works fine, however, as soon as I connect anything else to the dev board, it fails to init the sd card.

For example - a DS18B20 temperature sensor connected to GPIO 4 and 3.3v and ground, or even just an LED on GPIO13 with a 220K ohm resister to ground seems to make it fail.

This seems to be a power issue, however it happens when connected to USB-5 volt 2.5 amp supply, or the 3.7 volt battery included in the kit.

Any idea on how to fix this?

UPDATE:

I’ve figured it out after taking a deep dive into the libraries, specifically “SD_MMC.h”.
My code assumed the sd card was using pins only 2, 14, 15, the library shows it uses more pins:
* SD Card | ESP32
* D2 12
* D3 13
* CMD 15
* VSS GND
* VDD 3.3V
* CLK 14
* VSS GND
* D0 2
* D1 4

If you use any of these pins, it interferes with the sd card.

I changed my code to use GPIO pins 25, 26 and 27 instead of 4 and 12 and it seems to work ok now.

The program reads an array of five DS18B20 temperature sensors every 10 seconds and writes the results to a data text file on the SD card. A momentary push button starts and stops data recording, an LED indicates the status of the sd card and when it is recording data.

Eventually this will get a touch display, this is just phase one to test the reliability of the ESP32 to perform this function.

Bottom-line: If your SD Card is not behaving as it should make sure you are not using pins 2,4,12,13,14,15

2

Could you please provide a video of the issue? This will help us analyze and resolve the problem for you.

Please confirm that the wiring connections between the modules are correct and consistent.

Follow our example tutorial for wiring and operation. Also, please specify which example you were running when the problem occurred, so we can reproduce and address the issue.

3

Thank you for reaching out.
I found the issue - please see my updated post.
(It would be helpful if the tutorial mentioned what pins the sd card reader uses, or at a minimum, advise when using sd card not to use pins: 2,4,12,13,14,15)

4

Thank you for your feedback, we will update it