Here is the logo I use for my hardware (electronic) project to show it is open source:

Why I created it is well explained in episode #013.

You can customize and download the logo using the open source hardware logo generator. How it works is pretty well described in the source files.

The generator allows to export in the following formats:

• SVG: a vector image. the primer helps a lot to understand the format
• gEDA pcb: footprint for the electronic CAD software I use. the format is pretty well documented
• KiCad: footprint for the electronic CAD software I used, and which I can only recommend. the newer S-expression module format is ok documented
• eagle: footprint for probably the most popular electronic CAD. since version 6 they release the DTD for the XML library format, but without guideline it's not easy to use.

You can download the files thanks to FileSaver.js. And you can get all formats in a .zip file thanks to JSZip.

a brief history about the OSHA and MY open source hardware logo:

• Open Source Initiative logo, on which the current OSH logo is based
• 2011-02-00: call for logo for the Open Hardware Summit 2011
• 2011-03-03: call for logo closed, with 129 submissions
• 2011-04-05: public vote for 10 selected logos ended
• 2011-04-07: OHW logo selected: Golden Orb by Macklin Chaffee (vector version made by Brandon Stafford)
• 2012-08-02: OSHWA and OSI discussion about logo “issue”
• 2012-09-04: created my own logo
• 2012-10-17: OSHWA and OSI have an agreement (gray raster logo provided)
• 2014-04-30: new logo by Mateo Zlatar make during Open Hardware Summit 2014). only raster version has been provided
  • Brandon Stafford created a vector version (be doesn't know the original font)
  • Robert Spitzenpfeil created a KiCAD footprint
  • Nathan Dumont created another KiCAD footprint
  • no footprint for other CAD software is provided (e.g. gEDA pcb or EAGLE)