This is the logo I use for the hardware I design in my electronics projects.
It is simple, and more suited for being included in board layouts as it only uses lines and arcs. Here you can customize it, generate your own version, and save it for your favorite CAD tool (coralEDA pcb-rnd, gEDA pcb, KiCAD, or EAGLE).
I hold no rights on this logo, or withdraw any if applicable, and you can do whatever you want with it. It is intended to be used for open source hardware projects (which ever definition and licence you are using).
The source code for this generator can be found in this git.