Getting started with OpenEnergyMonitor
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:
Please select the type of system you are interested in:
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:
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.
- Raspberry Pi-based energy monitor
- 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)
- 1 X Clip-on CT sensors (the emonPi can accept up to two CT sensors; one is included as standard with the emonPi)
- 1 x AC-AC voltage sensor adapter (optional but highly recommended)
Power Adapters Required:
- 1 x USB 5V DC PSU
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.
- Energy monitoring add-on node
- Optional add-on if more than 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.
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)
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)
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
View hardware comparison table