HardwareRaspberry Pi 4 (3) Unicorn HAT HD Unicorn HAT on top of Raspberry Pi stack. (Yes, there is already an LED failure.) Cable and Unicorn HAT mount so LED array can be on top next to track and Raspberry and servo HATs can be under the layout. Two Unicorn HD HATs Unicorn Header Copyright © 1 June 2019 by No One's Business. All Rights Reserved.