This is a look at the brain surgery which [Tim] performed on a Happy Meal Toy. The McDonald’s package meal perk comes with one of several different Despicable Me 2 characters. But [Tim] wasn’t a fan of this one since you had to blow in it to make noise. He grabbed a 555 timer and added his own circuit to the toy which turns it up to 11 (seriously, turn your volume down before playing the video).
Disassembly includes removing a screw which needs a 3-sided screwdriver (protip: use a bench grinder and a cheap screw driver to make your own). There’s also some prying to get into the skull and then its time to work on the slide whistle. The blue tube is a regular slide whistle which you blow into from the back and pull on the red goo to change the pitch. [Tim] added a photoresistor to the mouthpiece and an LED on the slide. Moving the light source changes the intensity which is one of the adjustments to make 555 circuit howl.