Hardware addon for your Android devices.

Hello. Now I'm working on a hardware addon for Android devices to turn it to the real shot timer. This device will cost about 10-20$. Moreover, I'm planning to publish its schema in this blog and you will be able to assemble it at home less then 5$. This addon will work with my application and will probably have a hardware button to start the timer. I think it will be next month.

Thank you.