There is a develop guide about Camera in the Android Developer. However, if you follow the guide and build an app, you’ll find that the ratio of the image displayed on the screen is wrong. I’ll try to provide a solution about this problem in this article.

There are some problem when running pcscd on MacOSX. Sometimes my macbook cannot detect the ACR122 driver.

For example, the first time I execute the example in libnfc:

I’ve spent some time trying to use Proxmark3 via an Android phone. The information in the Internet were a little disordered or maybe out of date. Therefore, I write the steps down in here.