Description:

Our project is to build a household Watt-hour meter which will monitor four circuits from an interface with the circuit panel in a home. The design for the DWM includes sampling voltage and current waveforms, putting the data through algorithms to find the power and energy, and outputting the information to an LCD display, see fig 1. The interface will have two buttons to switch between displaying each of the four circuits that will be monitored, as well as switch between the values of voltage, current, power and energy for that circuit. One of the constraints of this design is that the energy values for each circuit must be saved and stored whenever power is removed from the device. EEPROM and a low power interrupts will allow us to store the information whenever power is removed. As shown in the block diagram, the design makes use of clip-on split core current transformers so no wires will need to be disconnected for current measurements. This not only makes the DWM simpler to use, but also less hazardous.

Remaining work:
A lot of coding
Documentation/posterboard

Picture of Device (11/21/2005)

Fig. 1 [Flow chart of design]

Fig. 2 [sampling diagram]

Fig. 3 [Details of microprocessor connections]

At the conclusion of the project the following items will be complete:

1. The device in proper working order
2. An instruction booklet explaining how to use and install the device as well as safety warnings.
3. Four current transformers (removable)
4. Power ratings and tolerance data