Remove one LED from the propeller to add a vibration switch (or directly add to the blade).

First, connect one pin of the vibration switch to the button cell’s cathode, and connect the LED’s anode to anode of the cell.

Then wrap the cell with the electrical tape to avoid the other pins of the switch and the LED touching the button cell.

Next, connect the other pins of the switch and the LED button cell, and fasten by soldering. Then glue this whole button cell to the prop.

Here you need to mind, place the head of the vibration switch facing the center of the propeller. Thus the LED circuit will be on by the small ball in the vibration switch under centrifugal force. Otherwise, the LED will not shine during the spinning.