I always forget which GPIO pin is which, and what leg of an LED is ground, so I made a laser-cut mounting board for the Raspberry Pi that tells me which GPIO
Raspberry-Pi-CNC-Board-2 | Protoneer.co.nz
Home-made CNC laser engraver - Raspberry Pi
LightBurn - Raspberry Pi Trick for a Wireless Laser Cutter - Tips and Tricks - LightBurn Software Forum
Convert That Cheap Laser Engraver To 100% Open-Source Toolchain | Hackaday
Arduino CNC Shield Raspberry Pi Enclosure- Stack | Protoneer.co.nz
A Grbl Raspberry Pi Hat at Buildlog.Net Blog
fun of DIY: A Raspberry Pi controlled mini CNC Laser engraver [last update June 6, 2017]
3-Axis 32-bit ARM Based CNC Controller,GRBL 1.1F USB Port CNC Engraving Machine Control Board with Fan Cooling,Support 500W Spindle/NEMA23 Stepper Motor/Laser (A4988+Fan) - - Amazon.com