How android weights coin

Hi i want to know that how can i weight the coin in android phone. I want to develop an application in android where i put the coin on the screen of the device and device will weights the coin and show me the results. there are some application in I-Phone who does this work. Is this possible in the android or not? If possible then how can i im开发者_运维百科plement?

I have lots of research in this topic but i don't get any stuff regarding this please help if you solve this problem.

As far as I know, no android phones have a built-in digital scale, which would make this task rather impossible...

There is an Android metal-detector. I've used it successfully for ferrous metals, but coins are rarely ferrous.