Review on ⚡️ 5V Relay Module for Arduino Raspberry Pi DSP AVR PIC ARM - JBtek 4 Channel by Andy Edwards

They work great with Arduino. Note, however, that they draw enough 5V current that you can't reliably use more than a kit or two powered directly from the Arduino. At three, I was letting the Arduino's internal voltage drop, resulting in random resets. The solution is simple: just supply the pins of these modules with 5V from another source. Make sure the ground is on the same plane as the Arduino as the control pins will use it as a reference. I soldered a thick wire on the bottom to connect all 4 center pins. They are aligned so you can do this without hitting other pins. This allows a single connection to provide output power (e.g. 120 VAC) for all four relays in the set. Of course you have to be careful that nothing of the live wire touches the live wire!