System Overview


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The OpenEnergyMonitor system has the capability to monitor electrical energy use / generation, temperature and humidity.

The system is made up of five main units. These can be assembled and configured to work for a variety of applications. The system is fully open-source, both hardware and software. All hardware is based on the Arduino and Raspberry Pi platforms:

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The OpenEnergyMonitor system can be used as a simple home energy monitoring system for analyzing real-time power use and daily energy consumption.

The hardware options to set up a home energy monitor are as follows:


emonPi

The emonPi is an all-in-one Raspberry Pi based energy monitoring unit making for a simple installation where Ethernet or WiFi is available at the meter location.

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

emonPi

  • Raspberry Pi-based energy monitor
  • Install next to utility meter
  • Local & remote data logging with Emoncms, our open-source web-app for processing, logging and visualising energy and other environmental data, such as humidity and temperature
  • Requires WiFi / Ethernet plus 2 x power outlets
  • Requires pre-built SD card image (included)

Sensors Required:

Power Adapters Required:

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emonTx (optional)

The emonTx is a remote sensor node. Data is transmitted to an emonPi or an emonBase via a low power 433MHz radio.

Note: as an alternative option, the emonTx can be used ‘standalone’ with an ESP8266 WiFi module running EmonESP to post directly to Emoncms without an emonPi / emonBase. See Using the EmonTx v3 with the ESP8266 Huzzah WIFI module

The emonTx can monitor up to four 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. 4x AA batteries can be used to power the emonTx if AC power is not available.

emonTxV3

  • Energy monitoring add-on node
  • Optional add-on if more then two circuits need to be monitored or if WiFi / Ethernet connectivity is not available at the location of the utility meter
  • RF Range is approximately similar to home WiFi and can be affected by obstacles e.g. thick stone walls
  • Up to 2x emonTx can be connected to a single emonPi
  • To connect an emonTx see: Setup > Adding Energy Monitoring Node

An emonTx can be powered by 3 x AA batteries; however, if possible, it is recommended to power the unit with an AC-AC adapter to provide an AC voltage reference for more accurate Real Power and VRMS calculations.

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Optical Utility Meter LED Pulse Sensor (optional)

  • Optional add-on sensor for interfacing directly with utility meters
  • Compatible with all utility meters with LED pulse output
  • Compatible with emonPi & emonTx (one pulse sensor per unit)
  • Reports exact amount of energy (Wh) reported by utility meter
  • Cannot measure instantaneous power
  • Best used in conjunction with clip-on CT sensor(s)

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emonBase (alternative to emonPi)

  • Web connected gateway: Raspberry Pi + RFM69Pi RF receiver board
  • No on-board energy monitoring functions
  • Receive data via low power RF (433Mhz) from emonTx or emonTH
  • Local & Remote Emoncms data logging
  • Runs the same software stack as the emonPi
  • No LCD screen to display local IP address or shut-down button
  • Knowledge of SSH highly desirable
  • Requires pre-built SD card image (optional extra)

View in Shop →


Providing real-time and historic information on your solar generation and demand matching, it will help you make better use of available solar power.

The hardware options to set up a solar PV monitor are as follows:


emonPi

The emonPi is an all-in-one Raspberry Pi based energy monitoring unit making for a simple installation where Ethernet or WiFi is available at the meter location.

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

emonPi

  • Raspberry Pi-based energy monitor
  • Install next to utility meter
  • Local & Remote Emoncms data logging
  • Requires WiFi / Ethernet plus 2 x power outlets
  • Single unit required to monitor solar PV, provided the generation and site-consumption feeds are in the same physical location and WiFi/Ethernet connectivity is accessible at this location
  • Requires pre-built SD card image (included)

View in Shop →



emonTx (optional)

The emonTx is a remote sensor node. Data is transmitted to an emonPi or an emonBase via a low power 433MHz radio.

Note: as an alternative option, the emonTx can be used ‘standalone’ with an ESP8266 WiFi module running EmonESP to post directly to Emoncms without an emonPi / emonBase. See Using the EmonTx v3 with the ESP8266 Huzzah WIFI module

The emonTx can monitor up to four 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.

emonTxV3

  • Energy monitoring add-on node
  • Required if solar PV generation and site-consumption feeds are located in separate locations or if WiFi / Ethernet connectivity is not available at utility meter
  • RF range is approximately similar to home WiFi and can be affected by obstacles e.g. thick stone walls
  • Up to 2x emonTx can be connected to a single emonPi
  • To connect an emonTx see: Setup > Adding Energy Monitoring Node

An emonTx can be powered by 3 x AA batteries, however this is not recommended for solar PV monitoring application since sensor adapter is require to determine direction of current flow and accurate VRMS & Real Power calculations.

Sensors Required:

Power Adapters Required:

View in Shop →



Optical Utility Meter LED Pulse Sensor (optional)

  • Optional add-on sensor for interfacing directly with utility meters
  • Compatible with all utility meters with LED pulse output
  • Compatible with emonPi & emonTx (one pulse sensor per unit)
  • Reports exact amount of energy (Wh) reported by utility meter
  • Cannot measure instantaneous power
  • Best used in conjunction with clip-on CT sensor(s)

View in Shop →



emonBase (alternative to emonPi)

  • Web connected gateway: Raspberry Pi + RFM69Pi RF receiver board
  • No on-board energy monitoring functions
  • Receive data via low power RF (433Mhz) from emonTx or emonTH
  • Local & Remote Emoncms data logging
  • Runs the same software stack as the emonPi
  • No LCD screen to display local IP address or shut-down button
  • Knowledge of SSH highly desirable
  • Requires pre-built SD card image (optional extra)

View in Shop →



Temperature & Humidity Sensors

Temperature monitoring example


1. Wireless Temperature Hardware

emonTH

The emonTH is a long battery-life, easy to deploy, wireless room temperature and humidity sensor node designed for monitoring a building’s thermal performance.

The emonTH is powered by two AA batteries and is available with a choice of either DS18B20 temperature sensors or DHT22 based Temperature and Humidity sensors. An external DS18B20 temperature sensor can easily be connected to a screw terminal block to provide external temperature readings.

emonTH

  • Wireless temperature & humidity monitoring node
  • Compatible with emonPi & emonBase
  • 6 month battery life (2 x AA batteries not included)
  • Up to 4 emonTH nodes can communicate with a single emonPi
  • Internal temperature & humidity + optional external probe
  • Optional pulse sensor input

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2. Wired Temperature Hardware

DS18B20 sensor on RJ45

  • Compatible with emonPi & emonTx
  • Up to 6 sensors can be connected to a single emonPi / emonTx using RJ45 Breakout
  • Sensor wire can be extended using RJ45 cable and RJ45 Extender

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DS18B20 sensor on wire

  • Compatible with emonTx terminal block
  • Compatible with emonPi using RJ45 Breakout
  • Up to 6 sensors can be connected to emonPi / emonTx using RJ45 Breakout

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  emonPi emonBase emonTx emonTH
Main purpose All-in-one monitor & gateway Web-connected gateway Energy monitor add-on Sensor Node
No. CT sensor inputs 2 0 4 0
No. of voltage sensor inputs 1 0 1 0
No. of pulse counting inputs 1 - via RJ45 0 1 - via RJ45 1 - via terminal block*
No. of temperature sensor inputs 6 - via RJ45** 0 6 - via RJ45** 2 - internal + external
No. of humidity sensor inputs 0 0 0 1
Power supply 5V USB mini-B 5V mico USB 9V AC-AC / 3 x AAA 2 x AA
Local data storage (Emoncms) Yes Yes No No
Requires additional base-station No No Yes Yes
LCD Display Yes No No No

* Requires manual wiring into terminal block

* Requires RJ45 breakout board

Full Documentation on all hardware units in the Technical Resources section.

The emonPi and emonTx are designed to monitor single phase AC up to 100A. The system can work for some set-ups in the USA with some changes to the configuration. See user guide section Use in North America.

The emonPi / emonTx have been designed for single-phase AC monitoring. The emonTx can monitor ‘approximate’ 3 phase (assuming balanced phases) using modified firmware and 3x CT sensors + 1 x AC-AC adapter. Further reading


Video Guide


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