ESP32 Forum

Hello lovely people of the forum!

I just finished my first ESP32 project: A temperature controller using a simple temperature sensor and a relay to turn on/off a heating element for my ant-farm.
I have the wiring and all the components wired up and the script does exactly what it should. During development and testing the ESP32 was always connected and powered using USB on my Macbook (also using a USB A to USB C adaptor). Now, that I'm done, I wanted to use a USB charger to power the ESP32, but interestingly it does not work. The display glows up, but the content is not displayed (no script is being executed - Relay not working either) and the ESP32 is blinking its red LED (more or less consistently the whole time).

What I tried already is:
- Many different USB chargers. From smartphone charger with 0.5A up til 3A. USB type A and USB type C with an adapter.
- A 230V to USB power supply (bare pcb with components. This was what I wanted to use in the end)
- I also connected it back to my Macbook with the USB A to USB C adaptor where it was working perfectly fine again.
- Finding the solution in all forums and discussions i could find in several hours of searching.

I don't understand the possible problem. Should the USB power from the Macbook not be exactly the same than the one of a USB charger? I mean, it is just power. Plus and minus. 5 volts.
I don't get it...

Hoping for someone to enlighten me or providing a clue or a way to troubleshoot this. I appreciate every input!

Thanks and greetings from Vienna
Yannick

I am wondering if you tried to power by USB and 5v in at the same time? There is a diode D1 that may have shorted?
I now only power by USB when setting up. For my alarm panel, I use one of the excellent and tiny MP2307 regulators, set at 5v and fed into VIN...

https://www.ebay.co.uk/itm/MP2307-Adjus ... 2749.l2649

Hi Spile2,

thank you for the suggestion. I did not power it with 5V and USB simultaneously. What ground pin would you use with VIN, when not powering over USB?
I did use the USB power, since I have some of those USB chargers around. And most importantly, I really want to find out the reason, why this strange behaviour occurs.

I think I'm gonna order some of those regulators you suggested, since the form factor seems more appropriate, than my USB-chargers

I'll update, if I get new information.
THANK YOU!

Pin 2 was used for 0v
https://github.com/playelek/pinout-doit ... vkitv1.png

Hi, @yannick. I am facing the exact same issue? Were you able to solve it?

Could you measure 3.3 V power supply? If there is no power output of USB charger? Maybe it is the problem of USB charger, we find if the current is too low, USB charger will be switched off due to its protection mechanism.

ESP_LJH wrote: ↑

Wed Sep 22, 2021 3:46 am

Could you measure 3.3 V power supply? If there is no power output of USB charger? Maybe it is the problem of USB charger, we find if the current is too low, USB charger will be switched off due to its protection mechanism.

Thanks for your help.
I solved my issue. It was a grounding problem, solved by replacing ground wire. I suppose it was somehow damaged, even if not visibly cut or broken.