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

Delivery: Mine arrived with 3 bent pins sticking out of the plastic packaging. Luckily I don't plan on using all four channels, but the buyer should be careful - the packaging on it isn't particularly secure, as there's no foam or anything else to protect it in transit. My star rating is mainly based on this packaging issue. Functionality: If you use this with a Raspberry Pi, by default they will not start in the "on" phase when booting, but will be about halfway. All built-in LEDs on this device are dimmed, relays inactive, until you set GPIO mode (e.g. putting this in your rc.local file can minimize this problem. The specific two lines you need to add before "output 0 is "gpio write <pin> 1" and "gpio mode <pin> out", where 0 and 1 enable or disable the relay. Tip: If you plan to place this in a remote location, use cheap CAT .-5 cable for low voltage line. You can use 3 out of 4 pairs with almost one wire to fish through walls. Make sure cable length and corresponding voltage drop is not a problem for your application. : Well built.