Here’s the current version of my Lego interface for the Raspberry Pi. It uses an L298 H-bridge motor controller (covered in a previous post) combined with another of my 74HC541 buffers to protect the Raspberry Pi when connecting LEDs and servos.
The whole thing runs from a 5v plug-top power supply which is adequate for driving the 4.5v Lego motors along with a bunch of servos.
There’s a bit of scope here for making the whole thing more compact but that’s another step once I’m happy with the design. I need to add input connections so that the Lego creations can be fully interactive.
It would be also interesting to see if I could make this into a Lego case, perhaps with a bunch of plates combined with 1 x 4 x 3 Panels.