Switch in time

Next-generation RF intelligent plug aims to monitor power output of individual electrical devices and help cut energy consumption. Siobhan Wagner reports


As millions across the UK begin decorating their homes inside and out with Christmas lights, the extra power used will be adding to the country’s domestic consumption totally unchecked.

In a move aimed at monitoring the output of individual devices while at the same time helping to reduce energy use, two researchers at Essex University’s Department of Computing and Electronic Systems hope within the next few years to develop an intelligent plug.

John Woods and Steve Fitz have been awarded £90,000 by The Carbon Connections Development Fund to create a device indistinguishable from a 13A plug. This will be fitted to all future domestic devices in place of a plug so that all electrical items can be connected to a central control system within the home.

The plug will use a single integrated circuit and its central processor unit (CPU) called an Advanced RISC Machine (ARM) processor, which studies voltage and current in real-time as analogue signals are converted into digital signals.

ARMs are popular in the mobile electronics market because they consumer lower power than other CPUs.

The proposed plug incorporates an RF transceiver to relay information back to a central point in the home.

‘Home-owners will be able to see how much power every single device uses. You will be able to see if a fridge has failed, or if something has been left on that should not have been. It empowers people to make a real difference,’ said Woods.

Another feature of the plug will be its integrated motion sensor, which can detect whether there is not much activity in a room where, say, a desk lamp or a television might be left on. The plug will flag to the central controller that those devices are candidates to be turned off.

‘If something is turned off and you don’t want it to be, you simply flick the switch off and flick it back on again and the central controller will recognise that you don’t like that service being compromised,’ said Woods.

Domestic consumption is responsible for a third of the UK’s total electricity consumption, and the researchers believe their technology could help reduce energy use.

Woods pointed to the government’s ambitious targets on energy saving and emissions reductions, and said domestic technology would play a major part in meeting these.

Woods and Fitz are working on writing an algorithm that will allow users to better budget their consumption. So a user can register the amount of kW of power they would like to use a day. ‘They might register to say they only want to use 2kW hours/day and the central computer will try and balance that budget,’ said Woods. ‘If you start to exceed that, it will start to compromise the services.’

This will be ideal for certain domestic situations, such as when a mobile phone charger is left in the socket. The intelligent plug will be able to kill the power it consumes.

The researchers are also working on perfecting the technology inside the plug, and they say the method for information delivery will be finalised later. For their prototype plugs the pair are proposing to use RF technology, but a manufacturer in the future might ask them to use another method.

Intelligent plugs that relay inform-ation via Ethernet or Wi-fi are already available. ‘Yet they rather defeat the object because they consume a large amount of power while trying to save it,’ he said. ‘The best method will be something that isn’t out there yet.’

The researchers will have a batch of prototypes made by Ipswich company Circad, and they should be ready within six months. They will then be tested in the university’s apartment, iSpace, where hi-tech creations can be trialled in a home situation.

Woods estimates that the plugs would need to cost less than £1 each to be commercially viable, but that should be possible with mass production.

‘The most important thing we need is government support,’ he said. ‘With that we could make sure one of these plugs is in every future domesic appliance.’