ESP32 cannot be used for a long time

Rob Fries

Have you checked the output voltage of each section of your power supply, at the time when the system is unstable? It also seems like it could possibly be a software issue - ? Also, per MakerIoT2020's comments, depending on the power being drawn from your 3.3V output, the 7805 could indeed be getting very hot, and turning itself off due to thermal overload; when it cools down it would turn back on. Measuring the actual voltages would be the best way to isolate the issue. You may even need to look at the voltages using an oscilloscope of the answer isn't obvious (voltage completely wrong or zero).

Jean Redelinghuys MakerIoT2020

I need you to check some things and get back to me.. taking into consideration that the 7805 is current limited to about 1A ( lets say 800mA to not drive it too hard... What is the current consumption of all the devices in your circuit? Taking into consideration that your ESP32 will use about 320mA with possible higher spikes while actively transmitting via Wifi or BT... Then take into consideration the relay (about lets say 80 10 120mA, depending on what type... could be more), and then your fingerprint reader, and all other stuff... You are also powering a 3.3v regulator directly from the 5v regulator... that adds to the load... Without seeing your entire circuit, with a more detailed explanation as to what you are doing... I wont be able to give you a more accurate answer... What I do know it that ESP32's goes into a "brown-out" condition, resetting themselves, or even constantly restarting, when underpowered... so, seems you correctly identified the issue as PSU related...