Here is every product you need to get your singing pumpkins going:

Projectors - I personally use an Epson brand projector. One with 2,000 lumens and standard definition is ideal.

Media Player - I use a Micca Speck with a USB drive to loop my animation videos. This is the best method for looping your animations on Halloween.

Uncarved Pumpkins - You will need 5 uncarved pumpkins, real or fake. I use Funkins artificial uncarved pumpkins so I can use them year after year!

Speaker - I prefer to use a small portable speaker, such as the one linked below.

Spotlights - I recommend shining some accent light on your pumpkins. It will help your pumpkin faces stand out more. Also it will minimize projector backwash.