Is it possible to monitor power usage with just a RPi?

Hello everyone! I have been trying to get some information regarding only using RPi for power monitoring. There isn’t much information out there for someone new like myself to understand. So here is couple of my questions.

  1. Is it possible to use the emonpi software just with the RPi without using the shield? If so, where can I find information regarding connecting current sensors to Rpi?

  2. Is IOTaWATT similar to EmonPi? In short, what is the difference?


  1. No. The Raspberry Pi has no analogue inputs, which you need to be able to measure voltage and current.

  2. My understanding is that the Iotatwatt only measures and displays, it does not record data. To do that, it sends the readings to an emonPi (or a server running emonCMS).
    I suggest The IoTaWatt forum is a better place to ask a question that is specifically about the operation and use of IoTaWatt. That is managed by Bob Lemaire (@Overeasy), and he and the other users there are more likely to have the specific knowledge to help you.

You can find out more about IoTaWatt at the forum mentioned above or better yet in the github repo at GitHub - boblemaire/IoTaWatt: IoTaWatt Open WiFi Electric Energy Monitor

Iotawatt does record data. Up to fifteen years worth, the most recent year at 5 second resolution. It also has APIs to query and use that data with an integrated visualization application.

It is correct that it can also upload data to Emoncms, and also to an influxDB database - or both. Moreover, it maintains context and bulk uploads historical data after a communication outage, or simply on demand to load a new database.

Other differentiators might be:

  • IoTaWatt has 14 inputs vs 2 on the Pi.
  • IoTaWatt will work with any combination of popular CTs with no reprogramming or calibration required.
  • IotaWatt can report, historically or real-time, Volts, Hz, Watts, Kwh, Amps, VA, and PF
  • IoTaWatt can be used with three phase power.
  • IoTaWatt costs less.
  • Emonpi supports optical meter reading
  • Emonpi supports temperature sensors
  • Emonpi supports MQTT and OpenHab

On the back of this question…

If I have a Api and a Analog to Digital converter, (I have 2 x RaspIO ADC’s) and have multiple SCT-013-*'s and SCT-006’s.

Can I run Emonpi on it’s own as a home build, using the SD image, or do I have to use OpenEneryMonitor board ?