Arduino Energy Watt Meter with SCT-013 AC Current Sensor

Here is an easy to use solution to monitor the power consumption of your devices with Arduino. Right, you could take a ready to use Energy-Meter,IMG_20160523_014409252_HDR but then you can not transform the data as you want it. With this solution you have 100% control and you can transmit it to a media of your choice. My solution has a feature you can not find in any other library, I’ve fixed the < 100 Watt issue (doubled value). With a precision of +/- 10 Watt you will get a corrected value between 0-100 Watt.  Also you don’t need extra libraries.


What you need:

  • Arduino UNO / Ethernet / Mega + Ethernet Shield
  • 2 x 10 KOhm Resistors
  • 1 x 22uF Capacitor (or 10uF-100uF)
  • 1 x 3,5mm Jack-Adapter
  • SCT-013-XXX AC Current Sensor
  • Optional: Ethernet-Shield with SDCard
  • Optional: Realtime Clock DS3231 (Raspberry Version)


Wide range of options:

  • Request the Data over Ethernet
  • Log the Data into Micro SDCard 
  • Log the Data with Realtime Clock


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

  • readVALUE // * Read Watt Value *
  • getTOTAL // * Total Watt Consumption *
  • resetTOTAL // * Reset Total Watt Consumption *
  • cal // * Calibrate Offset Watt Value (bring it to zero) *
  • 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 *
  • clearLOG // * Clear SDCard Log Lines *


WattMeter Screen App (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.



If you want all, then you need an Arduino Mega 2560 with Ethernet Shield, because the 32K of the Arduino UNO or Arduino Ethernet are not enough. 

IMG_20160523_014542494_HDR      IMG_20160523_014932464      IMG_20160523_014736916            

HINT: The SCT-013 AC Current Sensor you have to clip around “one wire” (L), not the whole cable with 3 wires (L,N,PE)