If you lot hollo upwards the article I did on the single smart relay switch, at that topographic point is directly an expanded version of this board that is likewise based on the ESP8266 WiFi module but packs fifty-fifty to a greater extent than extra cool features such every bit DC ability connectivity, 4 relays alongside optoisolators, 3.3V regulator, USB to UART converter, NodeMCU header for connecting OLED displays, every bit good every bit an LED for GPIO LED test.
The functionality of the single-way relay switch was already bang-up for controlling lite bulbs remotely via an android phone. But now, alongside the four-way relay switch board you lot tin laissez passer the axe connect fifty-fifty to a greater extent than sensors to the board in addition to command 4 lite bulbs at the same time.
The 4 relay board likewise features a 100-230V /5V AC/DC ability render to connect the board straight to mains electricity, 2 headers for connecting digital sensors, every bit good every bit a USB to UART converter onboard for programming the ESP8266 to your liking.
By the way, it's non simply light-bulbs you lot tin laissez passer the axe control. You'll likewise hold upwards able to utilization a WiFi smart ability strip alongside 4 sockets in addition to 4 two-way switches to command dissimilar appliances inwards parallel alongside each other, then you lot tin laissez passer the axe plow on i appliance without having to plow on the others.