Expandable 6 Channel ESP32 Energy Meter Main Board

Description

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.

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
• 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:

• 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.
  • Libraries for CircuitPython & MicroPython

Backorder status

10/09/19 – Almost all backorders are now filled. Current lead time is 1-2 weeks on main and add-on boards.

9/26/19 – Orders placed between 9/11 and today will be filled in 1-3 weeks.

A small revision to the boards was made to allow a better voltage signal to be read by the meter IC. Some unused pads next to the current connectors were also removed.

9/20/19  – The custom headers finally arrived and more add-on boards are currently being assembled.

9/13/19 – Unfortunately, the headers needed to finish the add-on boards have not arrived despite being promised this week from our supplier. Apologies to those patiently waiting.

9/6/19 – We expect to finish the backlog of 25 orders by the end of next week. Orders shipped between now and then will have a voltage calibration that is much lower at around 7k for 120V and 14k for 240V. They way to tell what board you have: R26 & R28 will be all black. Boards with a higher calibration will have a white dash in the middle of R26 & R28.

9/4/19 – We are currently waiting on some custom connectors to be delivered for add-on boards. They will be here next week and expect to have the remaining ordered shipped by then. Those connectors include the long 20 pin female headers, and the CS pin jumper headers.

8/24/19 – So far 40 orders have shipped with 20 to go. If you ordered an add-on board, 12 have shipped with 10 remaining. There is a slight delay while custom headers for these boards are made. They will be in next week.

For v1.2 of the board your voltage calibration will be high, >64,000. This is normal. Current calibrations will be around 30,000. If you require the voltage calibration to be higher than 65,535, we recommend calibrating to half the voltage needed and then using a scale factor in software to double the voltage value. Keep in mind that if you are also getting power readings from the meter, they will also have to be doubled.

For more updates, please see our Instagram page!

7/24/19 – Testing is complete of v1.2 and everything works as expected. Changes from v1.1:

• Fixed the power output of the on-board power supply
• Fixed voltage reading being lower than expected
• Fixed being able to read a second voltage from the 2 pin jumper – if you have v1.1, do not use the second voltage jumper pins!
• Tied 2 LEDs to CF1, which is a pulse for active power
• Added ability to tie the all voltage readings (there are 3 per IC) together via solder jumpers. This allows for more detailed metering values to be read.
• Moved screw connector terminals back a bit

We expect to start delivering orders that were placed on 7/8 by next week after assembly and testing. It will take 2-3 weeks to build all of the boards that were ordered up to today.

7/13/19 – A revision of the main board and add-on board is currently being worked on to correct an issue with low power output from the on-board power supply. We expect to have a new batch of PCBs in next week. Then another 1-2 weeks to assemble and test the boards.

If you ordered between 7/1 and now, you’ll receive the new revision unless you request the current revision. Orders will be processed in the order that they were received.