The JM Power Meter (JMPM) is a high resolution non-invasive energy monitoring device with support for sensing the current on up to 5 circuits and voltage. Based on the designs by OpenEnergyMonitor, this offers 12 bit analog to digital converters as well as a user selectable measurement range of either 120A or 35A per channel with better than 1 watt resolution at the 35A range. The hardware and software are all Open Source.
I have two general use cases for this in my home.
- Monitor energy production from both solar panel arrays
- Report costs based on current energy rates for various loads.
- Monitor energy usage and costs
- Monitor heath of internal components
- Heating element
- 3 water Pumps
- Monitor Hot Tub temperature
- Control the Hot Tub on/off state
Based on the ESP32 controller by Espressif, this features:
- 5 channels for Clamp On Current sensors
- SCT-013-000 (Amazon)
- Jumper configurable measurement range. No soldering required, just insert a jumper cap!
- 35 Amp Default
- 120 Amp Extended Range
- Support for a near unlimited number of DS18B20 temperature sensors.
- You’re only limited by the quality of the cable you use.
- Onboard high accuracy temperature monitor.
- ESP32 Microcontroller
- (Optional) Relay output
- Can switch loads of up to 2A DC
Eagle Board and Schematic for JMPM:
The firmware is developed with the Arduino toolchain and is available in GitHub.
All functions are exposed as a JSON REST API. A minimal web interface simplifies device utility.
Work in progress
- 2020 05 17 – First revision of firmware is complete.
- 2020 05 08 – The first 15 prototype devices has been sent to be manufactured by JLC PCB
- 2020 05 07 – Design completed.
- 2020 05 06 – Design process started.