rbx led assembled

The LED Brick is made from a 5mm 3.7V LED found in many Arduino starter kit. 

part 5mm led

The anode of the LED (longer leg) is connected to the microcontroller pinout, while the cathode (short leg) is connected to GND via a low value resistor.

rbx led schematic

Parts list

5mm 3.7V LED 1
100 ~ 220Ω resistor 1
2-pin JST XH connector (male) 4
M2 self-tapping screw 4


Solder the resistor to the cathode (the shorter leg) of the LED.

rbx led circuit 01

Solder the JST XH connector to the assembly. Make sure to get the polarity right (black wire to the resistor).

rbx led circuit 02


Print out the enclosure parts on a 3D printer.

 rbx led 3dview

Insert the LED into the cut-out in the top piece, and arrange the wires in the grooves. Optionally secure the wires with a small amount of hot glue.

rbx led assembly 01

Secure into the bottom piece with 4 x M2 screws.

rbx led assembly 02

Line up two 2x1 brickbases on a faceplate, two rows apart. Surround the brickbases with a few other bricks to assist in alignment.

rbx led assembly 03

Add two drops of super glue on each brickbase and mount the module. Press and hold for 60s.

rbx led assembly 04

The finished module:

rbx led assembled