Mac OS X CH340 USB driver

The low cost Arduino clones are fitted with the CH340 USB interface chip that will need some software installing for your computer to be able to communicate with it.

It’s a simple matter of downloading the driver from here and running the installer.

The alternative is to buy an Arduino with an FTDI FT232RL chip on. A branded Arduino comes in at around £20. A clone with this chip on can be had for around £10 locally, £4 from China.