I have a number of these in use with ESP Home and Home Assistant, but want to use the same power supply for a LED Circuit.
So the power will be applied to the ESP01 on the VCC and GND as normal, But I also want to use the same VCC and Ground to be switched via the relay to control a Simple 3.0 Volt battery leds from Ikea ( removing the batteries and replacing with the USB Power ).
Everytime I try this layout I get a squeeling relay / flashing relay and / or a bad wifi signal ( assuming a power issue or the like )
Is there a way to use the USB power like this ? Or do you have to keep the power circuits isolated ?
Thanks
You should be able to do this. No isolation required. Assuming your power supply is capable of supplying the two loads (LED and ESP relay board).
Sounds like the load is dragging the power supply voltage down causing the relay to turn off, which then allows the voltage to rise back up which turns the relay on which drags the voltage down, etc…
Just confirmed I am using a 2 A USB Charging Brick.
So the leds were normally powered by 2 x 1.5 Volt AA Batteries ( in Australia Energiser Batteries )
I am now powering the ESP-01 and Relay and the LED’s via the 2A USB Charger like these :
Are those bricks actually capable of powering an ESP-01 / Relay and LEDS full time or are they only for charging phones ??
You mentioned 3V led and use a 5V powersupply?
Maybe that causes a voltage drop when power is turned on…
Can you try to put 2 LED’s in series, so they both will get 2.5v instead of 5v ?
Worth a try 
PS, if you know the power consumption, you can calculate the value of a resistor, and use to to bring the voltage down