This is the app I used to check 2-way communication with my puck, using the free PuckJS plugin.

It offers to enable Bluetooth on the phone if needed.

It then gives you the option to connect to the same puck you connected to last time the app was run or to scan for a different puck.

Once connected it displays a logo button, suggests you press your puck and requests the battery status from the puck.

When the puck is pressed "State: Down" is displayed, the phone squeaks repeatedly and the logo changes until you release the puck.

When the puck is released, the sqeaking stops and the logo reverts to the original. "State: Up" is displayed.

When you press the logo button on the phone, three values are requested from the puck and displayed. The green led on the puck also lights up until the logo is released.