What you're trying to do requires correct speed and timing. A project called Spin FX was published in the Silicon Chip magazine few years back. The article read great! There's still even KITS available for it. (Stock is very limited though)
<a href="http://www.dse.com.au/cgi-bin/dse.storefront/4647d6c8069df9ae2742c0a87f9c074f/Product/View/K3005" target="_blank">Click here to purchase a KIT </a>.