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Open-source tools for energy monitoring and visualisation
Updated: 1 min 7 sec ago

emonPi Vs emonTx V3 Comparison

Sat, 11/04/2015 - 09:46
Here's a quick comparison table comparing the emonPi (currently active on Kickstarter!) to our existing emonTx V3 energy monitoring unit:
emonPiemonTx V3

It is no secret that there is much similarity between the two units, both are cut from the same cloth. Both units use the same ATmega328 Arduino IDE compatible microcontroller and front-end CT channel signal processing which gives identical monitoring accuracy. 
The emonPi is most suitable over the emonTx V3 for home or small business whole circuit energy monitoring and also solar PV where Ethernet or WIFI can reach the consumer unit. Being a one-box-solution and with its status LCD the emonPi is quick and simple to install and maintain. 
For larger systems where there could be multiple transmitter nodes and more channels to be monitored the emonTx V3 could be most suitable. The emonTx V3 transmits it's readings via RF (433Mhz) to an emonBase web-connected base station (Raspberry Pi + RFM69Pi). Multiple emonTx V3's can be used with a single emonBase
The emonTx V3 has the edge over the emonPi when it comes to powering the unit, the emonTx V3 can be powered directly from the AC-AC adapter while also taking an AC voltage waveform sample. Due to the higher power requirements of the Raspberry Pi the emonPi requires an additional 5V DC USB adapter. 
Struggling to decide? It's also worth noting that the emonPi and emonTx V3 can work together. emonPi by default also functions as an emonBase; as well as local monitoring the emonPi can receive data via RF from multiple emonTx V3 and other remote nodes such as emonTH temperature and humidity room node. 
For further details of the units see the Technical Wiki documentation pages.

Categories: Blog

Introducing emonPi: Raspberry Pi based energy monitor

Fri, 03/04/2015 - 09:56


emonPi Raspberry Pi based energy monitor Kickstarter
It's an exciting time for us; this week (on the 1st April, unfortunate timing!) we launched a Kickstarter crowd funding campaign for our emonPi Raspberry Pi based energy monitoring unit
The emonPi has been in development for the past 12 months or so, if you have been lurking on the forums you have probably seen activity on the emonPi's open development forum thread. Thank you everyone who contributed. 
The emonPi has been developed with input from the community, merging the monitoring unit and web-connected base station into a single easy to install and setup energy monitoring solution. 
The emonPi is fully open source hardware and software. It's been designed for maximum hackability and customisation being built on a fusion of two popular open source hardware platforms Arduino and Raspberry Pi.
emonPi Technical Features 
  • Two channel CT monitoring with AC sample input 
  • Compatible with Raspberry Pi model A, model B, model B+ and Pi 2 
  • Arduino compatible ATmega328 with ability to remotely upload sketches vis Raspberry Pi Serial 
  • RJ45 DS18B20 on-wire temperature bus to allow many temperature sensors to easily be added using a RJ45 breakout board for heat pump monitoring applications 
  • PWM and IRQ I/O's on RJ45 
  • Status LCD with function push button
  • Raspberry Pi shutdown button
  • RFM12B / RFM69CW with SMA antenna to receive or transmit data from other sensor nodes
  • Option to add OOK (on-off keying) transmitter footprint for controlling remote plugs etc. 
  • Option to add EEPROM to enable Raspberry Pi HAT compatibility (please get in contact if you have experience setting up Linux device tree). 
  • Open-source hardware, firmware and software 
  • High quality custom made, wall mountable enclosure
See the emonPi wiki for more technical info (currently under development).





We had fun filming a Kickstarter promo video, demonstrating some applications of the emonPi, Emoncms and the OpenEnergyMonitor system installed around where we are based in the mountain of North Wales, UK.  

Here's a video showing the emonPi installed and talking through how setup will work in practice. Having the LCD to show local IP address, status and uptime etc will no doubt make the system much more user friendly and accessible. 


The Kickstarter will be running until Apr 20 2015 9:46 PM BST, if we haven't reach our funding goal by then we will get nothing! Please help us share and spread the word :-)

Please help us by sharing our Kickstarter page with interested parties
We believe the opportunities and benefits of taking an open-source approach to smart monitoring and control challenges are significant; we hope to encourage others to start projects & businesses that also work towards a zero carbon future in an open way. 

Categories: Blog

Energy Display Options...

Thu, 19/03/2015 - 12:24
Sadly as of last week we have run out of emonGLCD kits in the shop and have decided to discontinue the emonGLCD for the moment. Preparing the through-hole kits is very labour intensive and the time and skill required to solder assemble is lagging behind our other pre-assembled SMT units.

Work has begun on a SMT pre-assembled replacement (see forum thread). However this would probably require significant investment in injection moulding tooling and commitment to high volume production. This would not would be a problem if we were sure on the design. However, I'm not sure if a standalone display is the right avenue to go down...

I am aware there that there is certainly value in an 'always on' wall mount / coffee table energy display. Being able to easily glance at the display throughout the day when your home really does remind me to switch off lights and appliances when not in use. As well as checking everything is turned off (base level energy consumption) when leaving the house. An always on display gives users a 'feel' for how much energy various devices use as the display increases or decreases in real-time as a device is switched on or turned off.

The future is mobile, everyone has at least one mobile device and increasingly as these devices are upgraded there are a large number of perfectly working just a bit slow older devices which could easily be given a second life as an energy display. This could help reduce the number of devices which end up being recycled or worse put into landfill, therefore helping to save energy in more ways the one! Old second hand Android phones or tablets can be picked up on Ebay for less than we could make an emonGLCD!

I recently repurposed an old Nexus 7 tablet (2012 model) with a cracked screen as a home energy display displaying Emoncms MyElectric. I installed an app to keep the screen on all the time when plugged in charging. The tablet uses 5W of power. An added advantage of using a mobile device as an energy display is they are 'mobile'! The display can easily be moved around the house to support investigation power consumption of various appliances.

Much work could be done on the software side to make a really nice packaged Android app for Emoncms which would support an energy display mode, useful features might be:

  • Intelligent screen-on-off e.g the display could turn off at night, when energy falls to base level consumption indicating the house is unoccupied 
  • Using the tablets motion / proximity / light sensor to sense movement to turn screen on-off
  • If device has an AMOLED display only certain pixels could be lit up to save power, like on the Moto-x Active Display 
  • Auto start at startup and full screen mode 
  • Home screen widget to be used if user does not want to decicate a devices solely as an energy display or to be placed on current mobile home screen to enable quick checking of power consumption / temperature etc when out and about.    


Emoncms MyElectric on Nexus 7 with cracked screen
A super low power alternative could be to use an old e-reader with an E-ink display. Here's Emoncms MyElectric running on a hacked Nook Touch.

Emoncms MyElectric on Nook TouchHead over to the forums and let us know what you think...
Discussion Thread: http://openenergymonitor.org/emon/node/10353
Categories: Blog