We already have support for generating apple wallet passes. For this to be used in the actual event we need to have support for Google wallet passes as well since many people will have android phones. To do this task you need to

1. Understand how a google wallet pass works and find a library that can be used for portal. This is the related documenation: https://developers.google.com/wallet/generic
2. Understand how the applet wallet is integrated with portal since google wallet implementation needs to have feature parity at least for the basic features like having a pass with qr code.
3. Implement google wallet passes and check them with an android phone to see if they work properly. If you don't have an android phone you can use an android emulator to try it out. I will help with testing it on an actual device later.