What is it?

The Expandable 6 Channel ESP32 Energy Meter can read 6 current channels and 2 voltage channels at a time, and can be expanded via add-on boards to monitor up to 42 current channels and 8 voltage channels, in real time, and in great detail.

Much like our Split Single Phase Energy Meter, the 6 channel uses current transformers and an AC transformer to measure voltage and power the board(s)/ESP32. The main board includes a buck converter to power the electronics and ESP32 dev board, which plugs directly into the board.

Features:

• Samples 6 current channels & 1 voltage channel (expandable to 2 voltage)
• Add-on boards (up to 6) can expand the meter up to 42 current channels & 8 voltage channels
• Uses 2 Microchip ATM90E32AS - 3 current channels & 1 voltage per IC
• For each channel the following can also be calculated by the meter:
  • Active Power
  • Reactive Power
  • Apparent Power
  • Power Factor
  • Frequency
  • Temperature
• Uses standard current transformer clamps to sample current
• 22ohm burden resistors per current channel
• Includes built-in buck converter to power ESP32 & electronics
• 2 IRQ interrupts, and 1 Warning outputs
• Zero crossing outputs
• Energy Pulse outputs per IC (4 per IC x2)
• SPI Interface
• IC Measurement Error: 0.1%
• IC Dynamic Range: 6000:1
• Gain Selection: Up to 4x
• Voltage Reference Drift Typical (ppm/°C): 6
• ADC Resolution (bits): 16

What you'll need:

• Current Transformers (depending on your application)
  • SCT-013-030 30A/1V
  • SCT-013-050 50A/1V
  • SCT-013-000 100A/50mA (13mm opening - 3.5mm connectors)
  • SCT-016 120A/40mA (16mm opening - 3.5mm connectors)
  • Magnelab SCT-0750-100 (screw connectors - must sever burden resistor connection on the back of the board since they have a built in burden resistor).
  • Others can also be used as long as they're rated for the amount of power that you are wanting to measure, and have a current output no more than 720mA.
• AC Transformer: Jameco Reliapro 9v or 12v. The positive pin must be 2.5mm (some are 2.1)
• ESP32 (choose one):
  • NodeMCU
  • Espressif DevKitC
  • DevKitC-32U if you need better wifi reception (don't forget the antenna)
  • Anything else with the same pinouts as the above, which are usually 19 pins per side with 3v3 in the upper left & CLK in the lower right
• Software (choose one):
  • Our custom version of EmonESP and the ATM90E32 Arduino library
  • The current dev release of ESPHome. Details on integration with Home Assistant are located here. and here on ESPHome.io
  • Libraries for CircuitPython & MicroPython

Why did you make it?

To make energy metering more affordable

What makes it special?

No other energy meter on the market is as affordable, has this many current channels, can be expanded with add-on boards, and output detailed energy metering data for every current channel.