Deluxe Four Relay Shield with External Power for Arduino
This has to be the most incredibly useful deluxe four relay shield for Arduino from PMD Way. We love it, as the designers have covered everything you could want in a relay shield.
First - the four relays are offset from the usual shield surface area. This allows you to stack more shields on top.
Second - the shield has an external DC power connector - with which you can feed in a power supply of a higher current to support all four relay coils being on at once along with powering your project.
Third - the relays are NOT fixed to specific digital pins on your Arduino - you can run female-to-female jumper wires (included!) or solder wires from the fitted inline header pins right to the relay's control pins (see below).
Fourth - an optocoupler is used to isolate the relays from microcontroller, so the Arduino circuit and signal outputs are not switching relays.
Finally, the shield is Uno R3-compatible with the extra I2C pins on the top-left staacking header.
And each relay can switch 250V AC at 10A or DC 60V at 10A.
Oh - and there's a prototyping area to add your own circuitry. And ICSP headers are brought out. A power LED. I think I'll stop now...