Check out this site to build your own Decelerator Helmet and find more detailed technical background!

 

The core of the helmet is a modified netbook on which runs a program written in the visual programming environment VVVV. It receives input from the remote control, regulates the speed of the video stream and sends them to the Head-Mounted Display and the external monitor.

For the video playback of the camera is used a library based on the VLC player. The remote control is a modified wireless mouse, which is connected to a little USB-plug in the inside of the helmet. The slide control knob on the remote-control defines the actual mode of the helmet (auto, press or scroll) by the combination of pressed mouse buttons and interprets the interactions of the scroll wheel accordingly.

The external display is the original monitor of the netbook, mirroring the images the user sees on the video glasses in the inside of the helmet for people on the outside.