OpenEnergyMonitor, monitor energy with RaspberryPi

By on November 23, 2015
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OEM is a project to develop open-source energy monitoring tools to help us relate to our
use of energy, our energy systems and the challenge of sustainable energy.

  • Wireless sensor nodes sending data at to a web-connected Raspberry Pi base-station.
  • Supports home energy, solar PV and remote temperature monitoring plug-and-play out of the box.
  • Fully open-source Arduino IDE compatible
  • Easily customized for a variety of applications.

The system is made up of five main units. These can be assembled and configured to work for a variety of applications from home energy monitoring to solar PV import/export monitoring and building fabric thermal performance monitoring. The system is fully open-source: both hardware and software, with documentation on everything from AC theory to sensor circuit design and application programming available in the Resources section.

The emonPi can monitor 2 x single-phase AC circuits using clip-on CT sensors. The emonPi can also monitor temperature & interface directly with utility meters via an optical pulse sensor.

The emonTx can monitor up to 4 × single-phase AC circuits using clip-on CT sensors. A plug-in AC-AC adapter can be used to power the unit and provide an AC voltage sample for real power calculations. 4 × AA batteries can be used to power the emonTx if access to AC power is not available.

The emonTH is powered by 2 × 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 easily be wired into a screw terminal connector to provide external temperature readings.

The emonbase is the internet gateway, relaying readings received via wireless from sensor nodes (emonTx / emonTH) to emoncms, an open-source energy monitoring web-application (see below). The emonBase is based on a Raspberry PI, a popular low cost Linux computer. The emonBase runs a web server with emoncms installed for local data-logging to an SD card, and it can be configured to simultaneously forward data to a remote cloud server. is a powerful open-source web application for processing, storing, visualising energy and environmental data.

Here you can see and download all the various software components for your custom application: Home | OpenEnergyMonitor

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