Review on 🔌 SunFounder 2 Channel DC 5V Relay Module with Optocoupler for Arduino R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi: Expand and Trigger with Low Level Control by Mark Gancio

SunFounder 5V Relay Protection Module for Arduino UNO 2560 1280 ARM PIC AVR STM32 (4 Channels) I am very happy with this board. Works with Arduino without any problems. It's responsive and VERY easy to use. However, remember that his logic is active low. So when power is first applied from the Arduino, the low state of the pins will cause the relay to turn on until the Arduino has time to position them. active high, turning them off. I solved this problem by using a 2N2222 transistor and a 1kΩ resistor between the Arduino pin and the 5V input of the relay. Now when the Arduino boots up, the relay board will NOT have power until the program tells it to. GREAT PRODUCT - HIGHLY RECOMMENDED!