powertagd

Solution to read electrical measurements sent by Schneider PowerTag sensors. These devices communicate with ZigBee Green Power and require precise control of the timings to work reliably.

A Sonoff ZigBee Dongle-E device (not the -P model!) with custom firmware is used as a gateway. The firmware is based on the NCP-UART firmware provided by Silicon Labs, modified to automatically send a special ACK reply which is specific to PowerTags.

Currently the firmware is tailored for Sonoff ZigBee Dongle-E devices, but can work on any devices using a Silicon Labs EFR32MGxx chip by adapting the pinout and rebuilding.

The powertagd command runs on the host and communicates with the dongle via USB/UART using Silicon Labs EZSP protocol. It processes the readings received from PowerTags. By default, each received measurement is simply printed to stdout in InfluxDB Line Protocol format. This output is intended to be piped to another app to process the data as needed.

The powertagctl command is used to create the ZigBee network, commission and configure the PowerTags.

Quickstart

1. Flash the firmware to the dongle. You can either use the built-in bootloader and upload the ncp-uart-hw-gp-multi-rail.gbl file, or flash the ncp-uart-hw-gp-multi-rail.s37 file directly with a JTAG debugger.
   Warning: Be prepared to hook a JTAG debugger to recover the dongle if anything goes wrong.
   Check out Sonoff firmware flashing to use the bootloader method, just replace the firmware with the one in this repo.

2. Build powertagd and powertagctl by running make in the src directory.

3. Connect the USB dongle and determine where it was mapped in /dev.
   On Linux it should be something like /dev/ttyACM0
   On macOS it should be something like /dev/cu.usbmodemXXXXXXXX

4. (Optional) Run a network scan and choose a channel. The closer the dBm value is to 0, the stronger the signal. In the following example the best picks would be channel 12 or 13.

   $ powertagctl -d /dev/xxx scan
   ...
   Starting energy scan...
   Energy scan result: channel 11: -64 dBm
   Energy scan result: channel 12: -43 dBm
   Energy scan result: channel 13: -45 dBm
   Energy scan result: channel 14: -78 dBm
   Energy scan result: channel 15: -87 dBm
   Energy scan result: channel 16: -87 dBm
   Energy scan result: channel 17: -87 dBm
   Energy scan result: channel 18: -88 dBm
   Energy scan result: channel 19: -87 dBm
   Energy scan result: channel 20: -88 dBm
   Energy scan result: channel 21: -83 dBm
   Energy scan result: channel 22: -59 dBm
   Energy scan result: channel 23: -58 dBm
   Energy scan result: channel 24: -78 dBm
   Energy scan result: channel 25: -89 dBm
   Energy scan result: channel 26: -88 dBm
   

5. Create a ZigBee network on your preferred channel:

   powertagctl -d /dev/xxx create <channel>
   

6. Commission PowerTags:

   powertagctl -d /dev/xxx pair
   

Finally run powertagd -d /dev/xxx to start processing the PowerTags readings.

Units

• voltage: V
• current: A
• active_power: W
• apparent_power: VA
• reactive_power: VAR
• power_factor: -100% to +100%
• energy: kWh

InfluxDB

powertagd has built-in support to send metrics directly to InfluxDB:

powertagd -d /dev/xxx -o influxdb \
  --url http://127.0.0.1:8086 \
  --org <OrgName> \
  --bucket <BucketName> \
  --token <XXX>

Below some sample Flux queries for InfluxDB/Grafana.

Get power values for a specific PowerTag id

from(bucket: "powertag")
  |> range(start: v.timeRangeStart, stop:v.timeRangeStop)
  |> filter(fn: (r) => r.id == "0x12345678" and r._field == "total_power_active")
  |> aggregateWindow(every: v.windowPeriod, fn: mean)

Where "powertag" is the bucket name and 0x12345678 is the PowerTag id.

Get daily energy usage for the past 30 days

import "date"
import "timezone"

option location = timezone.location(name: "Europe/Paris")

start = date.truncate(t: -30d, unit: 1d)
stop = date.truncate(t: 1d, unit: 1d)

from(bucket: "powertag")
  |> range(start: start, stop: stop)
  |> filter(fn: (r) => r.id == "0x12345678" and r._field == "total_energy_rx")
  |> aggregateWindow(every: 1d, fn: spread, createEmpty: true)
  |> timeShift(duration: -1s)

TODO

• Improve ash protocol error handling
• Finish MQTT support