Help with NodeMCU based smart switch The project I'm planning is to use a NodeMCU at each electrical board in house to control lights and fans via relays. Each MCU will communicate via MQTT over WiFi to a Raspberry Pi 4 from where I can control all lights and fans in the house. My doubt is:
Can the 3.3V NodeMCU drive a 5V relay like this 1 Channel 5V Relay Module with Optocoupler since I can't find any 3.3 V relays in India. Or must I use a logic level shifter? Or just use an ESP32 board (double price).
The relay I linked to couldn't be operated with 3v3 from the NodeMCU board. I was powering the NodeMCU via a breadboard power supply that had both 3v3 and 5v output (https://www.electronicscomp.com/mb102-breadboard-power-supply-module). I connected the Vcc and GND of relay to 5V supply on that module. the IO pin relay was connected to NoddeMCU. It worked fine and NodeMCU could switch it on and off.