8-Channel 5V Relay Module Board

If you want to build a “Smart Home” system where one Arduino controls the lights, fans, and outlets in an entire room, this is the board you need. It features 8 independent relays, allowing you to switch eight different high-voltage circuits on and off individually. It uses “Low Level Triggering,” which means sending a logical “0” (Ground signal) from your microcontroller turns the relay ON. Crucially, each channel is protected by an Optocoupler (a light-based isolator), which prevents dangerous high-voltage spikes from traveling back and frying your delicate microcontroller.