Energy Display Options...

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 Touch
Head over to the forums and let us know what you think...
Discussion Thread:
To engage in discussion regarding this post, please post on our Community Forum.