Review on SMAKN® 2 Channel Self Lock Interlock Arduino by Jason Flores

Extremely useful relay module, I will definitely buy more. To be honest, I bought this board because the "product description" was so cryptic that I had to get my hands on it to fully understand its functionality. Basically, I use the module's self-locking feature, which allows for a momentary button. to send a pulse (high or low) to lock and unlock the corresponding relay. The 2 miniature buttons (labeled S1 and S2) come in handy when prototyping or troubleshooting a circuit. They work in all three "modes" (TR: Trigger / IL: Lock / SL: Self-lock). However, it should be noted that they pull the relay's trigger signal low and therefore can only be used if you have the H/L level jumper in the low position. The product description also mentions a DC plug for connecting to a power supply; This board has no DC connectors, it looks the same as the photos above.