i don't know if this is a repost, but this is so cool.

watch the embedded video, for 50 bucks build a retina control open source device .

<object width="425" height="425" align="middle"> <param name="movie" value="" /> <param name="quality" value="high" /> <param name="wmode" value="transparent" /> <param name="FlashVars" value="title=The-EyeWriter"> <embed src="" quality="high" bgcolor="#ffffff" width="425" height="425" align="middle" allowScriptAccess="always" wmode="transparent" FlashVars="title=The-EyeWriter" type="application/x-shockwave-flash" pluginspage="" /></object><br /><font size="1"><a href="">The EyeWriter</a> - <a href="">More cool how to projects</a></font>