The drum mallet is the first switch. Just take it.
I don't have enough force
Maybe the hexipal could play the drum?
How?
You just need to rewire it to another mode. Some mode that would preferably wave the mallet.
Wave?
Didn't the hexipal with Vella wave it's flashlight?
Yes it did!
Great. When Vella has distracted Mother once, the hexipal is reseted to the warning mode. Copy the wiring from that to Shay's hexipal.
The order of the wiring can be seen from how the light moves in the wire.
The hexipal is waving
Great! Now, give it the mallet (It is the first switch in the power room.)
and put it in front of the drum.