This page and linked pages detailed below document how to build whole house energy monitor that has a display for easy, quick access to current energy use information, usb datalogging for detailed long term data storage and Internet connectivity for online graphing.
First a quick look at the installed setup:
The display unit consisting of 4 large green led 7 segments. On the right is a 6 mode – mode chooser so that you can select by turning the potentiometer (bottom – right) whether the display shows real power, apparent power, power factor, RMS Voltage, RMS Current, frequency or cumulative kWh used. The display is connected to the main unit by a cable that goes through the wall at the back of the display.
The Main unit
The main unit is the small box in the far left of pic below with the white CT sensor wire crossing the shelf over to the sensor clipped on to the main mains wire on the right. The main unit contains the Arduino, voltage and current measurement electronics, power electronics, usb pen datalogging and xbee wireless link.
The Ethernet unit
The ethernet unit is connected to the router, the small box on top of the larger box houses the wireless xbee link.
Web based graphing
For more pictures of the setup check out the picasa album here.
- Voltage measurement with step down AC to AC adapter
- Current measurement with CT sensor.
- Power for sensor board provided with same AC to AC adapter used for voltage measurement.
- Calculation of Real power, Apparent power, power factor, RMS voltage, RMS current, frequency, cumulative kWh.
- Display unit consisting of large green 7 segment display,
- 6 mode – mode chooser and red/green led indicator to indicate when grid is below and above 50Hz.