Puck.js, Raspberry pi camera

I think you've basically got two options:

• Use Puck.js as a device like a keyboard, and use it to send a keypress that your code then acts on: http://www.espruino.com/BLE+Keyboard
  
• Have an app on the Pi that scans Bluetooth and then acts on the data received. There are a few ways to do that, but maybe the easiest is this one: https://www.espruino.com/BLE+Advertising
  
  

Hope that's some help!