The main idea is to have a kit so that we can measure the electricity consumption, the temperature and the humidity in a building. The system should be scalable and be capable of enhancement with an array of different sensors (water and gas consumption, solar production, etc).
We could also think of adding a weather station.
The most appropriate solution for enabling us to do this is the OpenEnergyMonitor project, an end-to-end open-source energy monitoring system. It is Arduino / Raspberry compatible and composed of four key components:
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emonBase: this board collects the readings received wirelessly from sensor nodes. There is a RFM12Pi expansion board which can be plugged into a Raspberry Pi. The data can then be uploaded to an external web site (emoncms) and / or stored on an external harddrive connected to the raspberry (for local use).
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emonTx: is the main sensor node. It usually sits next to the electricity meter box and measures electricity being used or generated via clip on CT (Current Transformer) sensors. In addition to CT based electricity monitoring the emonTx has a pulse counting input which can be used for interfacing with smart meters and certain types of water meters. It also has a DS18B20 digital temperature sensing input which supports multiple DS18B20 temperature sensors on a single bus.
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emonTH: The emonTH is a long lasting, easy to deploy wireless temperature and humidity sensing node designed for use in building thermal performance monitoring. The emonTH is powered by 2x AA batteries and is available with a choice of either DS18B20 based temperature sensing or DHT22 based Temperature and Humidity sensing. An external DS18B20 temperature sensor can then be easily wired into a screw terminal connector to provide external temperature readings.
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emonGLCD: The emonglcd is a table top LCD display that is ideal for showing information such as current power consumption in an at-a-glance fashion. The display is a standard 128px by 64px LCD and so is fully programmable. The standard firmware can either show a simple home energy monitor style display or a solar pv import vs export display with ambient LED’s that glow green when a household is exporting and red when importing.