[Ladyada] takes some time out of her day to explain the common options available for connecting projects through USB. You may be thinking that you already do this with an Arduino. Well, yes and no. The Arduino uses one of these options, an FTDI chip that handles the USB on one side and spits out microcontroller-friendly voltage signals on the other. This chip can be used with your projects, a topic that [Phil Burgess] covered in great detail.
In the video after the break you’ll also hear about USB to serial converters which connect to the Universal Serial Bus and output the traditional 12-20V serial signals (with the exception of cheap knockoff cables like the one from last week). These need to be stepped down to 5 volts or less using a MAX232 chip to work with your project.