The new Arduino Esplora has been designed to emulate traditional input devices like a mouse or keyboard, and Arduino has developed to not only be a games controller.

With the new Arduino Leonardo board able to emulate USB keyboards and mice right out of the box, it seems the perfect time for Arduino designers to come up with a proper video game controller.

New Arduino Esplora Provides A Ready-For-Gaming, Customizable, Open Source Video Game Controller Darrell Etherington 5:59 AM PST · December 10, 2012 ...

Electronics maker Adafruit Industries has developed its own Arduino-compatible boards, including one called the Flora--and a few craft projects to go with them.

Teague Labs has created a peripheral any retro video game fan would love – a Power Glove VR controller for the HTC Vive VR system.

I use that in a lot of Circuit VR posts so you can click on a circuit and see it live. However, the simulator does not save the source code in the virtual Arduino. You have to do that yourself.