My friend Usman and I are collaborating long-distance on an Arduino project. He’s a software guy (by which I mean he’s a guy actually made of software. OK, not really, but almost) and doesn’t have time right now to get up to speed on hardware. So, I send him bits of hardware as needed. This is how we did the RFID iConveyor project.

In order for him to test sending signals to the Arduino’s digital out pins, I built this plug-in cluster of three LED with integrated resistors.

They’re soldered to a set of four right-angle header pins, and all share ground. Usman can plug this into the pins GND, 13, 12, & 11 and he’ll be off and running, with no need for a breadboard and jumper wire.