D1 Mini ESP32 Requires USB to Boot

ESPHome
1

Ive got a D1 Mini ESP32 and, like ive done a few times before, ive connected it to a strip of LEDs. The 5v power splits to both the LEDs and my ESP using the 5v pin.

However, it wont start up. I get a solid red light on it, but it doesn’t come online (web interface is down and the light ive configured to work with it in esphome doesnt show as available in HA).

When I plug it in via USB as well it does boot up as expected - with the little blue status light flickering and everything accessible.

If I boot it up in this way, and then disconnect the USB, it continues to run fine. But if I then power it down and back up again, back to square one.

Ive never encountered this before - is there something I can do to avoid having to run a separate USB lead to the D1?

2

Sounds like a brownout?

Can you try another high quality power supply (or is this fixed to the LEDs etc).

Are the LEDs off on boot? (To reduce competing peak demands).

I’ve also seen some instances where people add delays to the boot to spread peaky power demand.

I don’t really know, just ideas you could try.

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3

I had some ESP32 nodemcu32s that would get into a boot loop, possibly due to an under powered 3.3V voltage regulator. I fixed the problem by putting a 47uF capacitor across the 3.3V rail.

You might try to see if you are having a problem like this by monitoring the device using the USB serial interface. It will show you if the system is crashing and rebooting.

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4

I understand cheap clones in particular can be prone to this.

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5

I have encountered this problem as well.
As I traced the USB 5V power net through the PCB I noticed the schematic is not correct. The schematics found on the internet show the USB_VBUS connect through a simple diode and from there to the USB-UART chip VBUS pin. That is not true.
I discovered that the USB 5V VBUS voltage goes directly to the USB-UART chip and from there is goes to the diode and the 3.3V LDO regulator.
What this means is if you power the ESP32-D1-MINI from the 5V pin the USB-UART chip does not get powered and as a result holds down both the RST pin and IO0 pin.
To overcome this you have 2 options:

  1. power the ESP32-D1-MINI only from USB 5V
  2. short the input diode so that the 5V pin and USB VBUS are powered together, no matter the source (USB cable or 5V pin).
    Either way the USB-UART chip will get powered and release the RST and IO0 pins for the ESP to boot.

Hope this helps to others facing the same issue and copying the wrong schematic connection for the 5V external power usage.

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