IMG_20160530_180033202With some old Energy Meters it is not simple at all to convert the Power Consumption into digital datas. In my case I’ve used an old NXT Light Sensor from NXT Mindstorms, to measure the wheel mark of my Analog Energy Meter. One cycle is 1/75 KWh (13,33 Wh). To measure the mark of the wheel I’ve used an Arduino Mega, and to log and request the data I’ve used an Ethernet Shield with SD Card slot.  


What you need:

  • Arduino  Mega + Ethernet Shield
  • 1 x 10 KOhm Resistor
  • NXT Color Sensor from NXT Mindstorms
  • Optional: Realtime Clock DS3231 (Raspberry Version)


Ethernet Commands ( http://Arduino-IP?cmd=… ):

  • readSENSORVALUE // * Read Light Sensor Value *
  • setSENSORTHRES&value=590 // * Set Sensor Threshold Value *
  • getSENSORTHRES // * Get Sensor Threshold Value *
  • getTOTAL // * Total Watt Consumption *
  • resetTOTAL // * Reset Total Watt Consumption *
  • getRTC // * Get Real Time Clock as UNIX Timestamp *
  • setRTC&RTCtime=23:17:00;21.05.2016 // * Set Real Time Clock *
  • getLOG // * Get SDCard Log Lines *
  • getSelectedLOG&timestamp=1486930259   // * Get SDCard Log Lines from Timestamp till end *  NEW
  • clearLOG // * Clear SDCard Log Lines *


WattMeter Screen App for MacOS:

To view the Arduino WattMeter data I’ve written an App. Here you can select some ranges of the data to analyse what happen in the past time. In the future I will add more and more functions to support all possible WattMeter commands. Hint: For this app you need the Real Time Clock DS3231 and you have to set the correct Time.




IMG_20160530_180110117  IMG_20160530_180033202  IMG_20160530_175956355 IMG_20160530_175927614  schematic1  schematic2