Expandable 6 Channel ESP32 Energy Meter Main Board


SKU: EM-6chan Category: Tag:


The Expandable 6 Channel ESP32 Energy Meter can read 6 current channels and 2 voltage channels at a time. 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.

Up to 6 add-on boards can stack on top of the main board to allow you to monitor up to 42 current channels in 16-bit resolution, in real time, all at once!

This product is currently in the prototype stage, so components may change.

See the latest hardware and software documentation in the Github repository.

Backorder Status – 12/04/19 – Orders placed today will ship within a week.


  • Samples 6 current channels & 1 voltage channel (expandable to 2 voltage – requires additional AC transformer to measure additional 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 (CT1-CT3 & CT4-CT5) & 1 voltage per IC
  • For each current 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)
  • Active Power LED pulse for CT1-CT3 & CT4-CT5
  • SPI Interface
  • Measurement Error: 0.1%
  • Dynamic Range: 6000:1
  • Gain Selection: Up to 4x
  • Voltage Reference Drift Typical (ppm/°C): 6
  • ADC Resolution (bits): 16

What you’ll need:

Additional information

Weight 2 oz
Dimensions 4 × 4 × 1 in
CT Connectors

3.5mm, Quick Connect Screw

Change Log

12/16/2019 – v1.4
– Added optional micro-hdmi connection to connect the current transformer remote board. This allows for all 6 current transformer connections to connect to a remote pcb, which then connects to the main board via 1 micro-hdmi cable. Instead of 6 wires coming out of the meter, there can now be 1.
– Removed JP9-JP11 and connected all voltage channels together for each ATM90E32

10/15/2019 – v1.3 rev1
– Added voltage divider on ground for voltage channel 2

10/1/2019 – v1.3
– Added voltage divider on ground for voltage channel 1
– Added 20k pullup for voltage channel 1
– Changed all voltage dividers to 20k and 1k so voltage input from a 12v AC transformer is around 650mV
– Removed C37

8/1/2019 – v1.2
– Added C37 to connect neutral and DC ground
– Added solder jumpers JP9-JP12 to connect all voltage channel inputs together

6/1/2019 – v1.1 – Initial public release


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