This unit, in combination with the USB/I2C interface described elsewhere in this issue, may be used to switch four mains-powered devices on and off via the PC. Eight of these modules may be connected to a single interface, allowing up to 32 loads to be controlled. The system is ideal for a small home bus!Triggered by other articles on home automation in this issue, you may feel like investigating the possibilities of automating, or at least remote controlling, a couple of electrical devices in and around your home. If you do not want to rush off to the high street stores to buy a box full of ready-made modules working on a more or less familiar protocol, then home construction of a small system is a perfectly viable alternative.An I2C system can be used without problems for a small home bus comprising a couple of features for control and switching. Provided extra bus drivers are applied, distances of the order of tens of metres are easily covered. The connecting cable between the modules is reasonably simple as we employ 6-wire UTP cabling with RJ11 plugs. Also, there is a wide choice of ICs with I2C compatibility, serving an impressive number of applications.