http://chorder.cs.vassar.edu/ 2008-10-11T08:50:34-04:00 http://chorder.cs.vassar.edu/ http://chorder.cs.vassar.edu/lib/images/favicon.ico text/html 2008-05-21T14:51:34-04:00 Greg Priest-Dorman http://chorder.cs.vassar.edu/spiffchorder/sample_layout?rev=1211395894&do=diff1211395894 With around two dozen total components its hard to go wrong.  The chorder can be built on perfboard, stripboard, wirewrap or your can etch a pcb board.  If you create a layout, please send it to us, your layout may be just what someone else needs to help them build their board!  Please be sure to clearly state how you want to be listed when we post it.  From Name and email address (obfuscated by the wiki) to total anonymity, we will do our best to accommodate your request. Component numbers … text/html 2008-05-21T07:02:54-04:00 Greg Priest-Dorman http://chorder.cs.vassar.edu/spiffchorder/hardware?rev=1211367774&do=diff1211367774 The image below shows the schematics for the SpiffChorder hardware. The interface to the USB connection is handled with a few passive components. Since the USB communication is handled by bit-banging in the software, an accurate clock source is needed. A 12.000 MHz crystal provides this. Since the beginning of the SpiffChorder project, the AVR USB stack has been expanded to also work at 16 MHz and 16.5 MHz, but this has not been tested with the SpiffChorder.