Open terminal, and download Node.js package for arm processor. Curently the latest version is v5.5.0.
$ wget https://nodejs.org/dist/v5.5.0/node-v5.5.0-linux-armv7l.tar.gz
Uncompressed the package to any folder. It will create a new folder named node-v4.0.0-linux-armv7l
.
$ tar -xvf node-v4.0.0-linux-armv7l.tar.gz