I finally got around to modifying my TakaraTomy Transformers Masterpiece MP-36 Megatron. He has a cannon that has a button that makes sounds. I wanted the trigger to make the sounds, too!

The finished product on one side. The other side has no wire, obviously. I picked this side so that my right hand would partially hide the wire when holding it.

What you need: A switch, a soldering iron and soldering paste, a screwdriver, and a lot of force to open the cannon. I couldn’t figure out how to open it cleanly.

The cannon’s switch is peeking out, with two legs.

The other two legs on the cannon’s switch, when shorted, trigger the sound. So I could just add another switch on this.

This is how the switch goes back in, with my new switch’s wires coming out from the slot in the front. It looks like it was meant to be easy to modify, if you could figure out how to open it properly.

I didn’t manage to figure out how to open it, so I melted off the parts highlighted in red so it could go back in.