It 'a simple application that allows you to use an NFC sticker/tag as clock in/out. Place the tag where you want and whenever you touch the tag with your phone the app keeps track alternately of in/out actions, saving them in a database that can be exported to Excel
Play Store Link
BadgeNFC for Android - Home
With PRO key ( € 0.99) you can save your in/out actions on an online database and share them with a group of people ... for example, a small gym managed by a group of friends could put a preconfigured sticker and record to the online database all the clock in/out actions ... of course everyone has to have an Android phone with NFC chip ... but I guess you do not associate with Apple boys ...
For example, I'm using this app at my office: I placed an NFC stick near my company clock-in machine so I can compare my in/out actions with those registered from my company ...
I accept suggestions and / or criticism ... I'm not a developer by profession, only in my spare time ...
EDIT: Version 3.0 is out: now with new method to register actions; this method allow you to enter custom name, custom action and custom fields using a specific Uri/Url; let's say you are a baseball coach; you can assign to each of your user a custom NFC tag with his name, his category (using action parameter) and some other attribute (using custom_field parameter):
where bold strings can be edited by you to insert the values you want.