Energy measurement with SONOFF POWCT

 With a SONOFF POWCT i tried to measure my energy consumption:

https://sonoff.tech/en-de/products/sonoff-pow-ring-smart-power-meter-powct 

That worked quite well (display is really good). And because this thing had Wifi integration i tried to get the values to import them into my influx db.

But: This device is only talking to the cloud and you have to use eWeLink to see the data:

There is a web portal as well: https://web.ewelink.cc/#/ which is quite nice:

Problem: if you want a real history, you have to pay... 
There is a way to sniff the token inside the portal with the developer tools. Then you end up with a command like:

curl -s  'https://eu-apia.coolkit.cc/v2/device/thing?familyid=TTTTTTTTTTTT&num=30&beginIndex=-999999'   -H 'User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:143.0) Gecko/20100101 Firefox/173.0'   -H 'Accept: application/json, text/plain, */*'   -H 'Accept-Language: en-US,en;q=0.5'   -H 'Accept-Encoding: gzip, deflate, br, zstd'   -H 'Content-Type: application/json'   -H 'X-CK-Nonce: ZZZZZ'   -H 'X-CK-Appid: YYYYYYY'   -H 'Authorization: Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXX'   -H 'Origin: https://web.ewelink.cc'   -H 'Connection: keep-alive'   -H 'Referer: https://web.ewelink.cc/'   -H 'Sec-Fetch-Dest: empty'   -H 'Sec-Fetch-Mode: cors'   -H 'Sec-Fetch-Site: cross-site'   -H 'Pragma: no-cache'   -H 'Cache-Control: no-cache'

This Bearer token XXXX..XXX will expire every 30 days - so you have to get that again.

So i decided to install tasmota on this device. But that was not so easy. 

• Tasmotizer stopped with: Invalid head of packet (0x46)
  and with that i found some pages with
• Esptool / EspFlasher... they stopped with:
  Unexpected error: Error while retrieving firmware file 'https://raw.githubusercontent.com/Jason2866/ESP_Flasher/factory/bootloader/esp32/bin/bootloader_dout_40m.elf': 404 Client Error: Not Found for url: https://raw.githubusercontent.com/Jason2866/ESP_Flasher/factory/bootloader/esp32/bin/bootloader_dout_40m.elf
• So i tried the webinstaller  https://tasmota.github.io/install/ but
• Ubuntu with Firefox: not supported
• Ubuntu with Chromium: did not find the USB port
• Windows 11 with Edge: found USB port but no permissions
• Windows 10 with Edge: found USB port but installation stalled  
• Winner was: a fresh Google Chrome on Ubuntu

With that i installed the default tasmota.bin - and after a restart the SONOFF POWCT was dark. No LED blinked, display completely dark. My first thought: now i broke it....

However: giving up is no option - so i searched with my smartphone for Wifis and there it was: a Wifi named "tasmota". :)

So: configuration of Wifi completed and now i saw many modules - so which should i choose? There was an easy solution (thanks for the guys from tasmota!!!):

With Auto-conf you can just select "SONOFF POWCT" and after that display is showing the voltage etc... 

For getting the values as json, just a curl is needed:

/usr/bin/curl 'http://192.5.7.11/cm?cmnd=status0'

(for looking up the commands you can use https://tasmota.github.io/docs/Commands/#management)

and inside the json there is one substructure:

 "StatusSNS": {
    "Time": "2025-11-11T21:46:33",
    "ENERGY": {
      "TotalStartTime": "2025-11-10T19:32:01",
      "Total": 10.854,
      "Yesterday": 0,
      "Today": 10.854,
      "TodaySumImport": 10.854,
      "TodaySumExport": 0,
      "ExportActive": 0,
      "Power": 3356,
      "ApparentPower": 3413,
      "ReactivePower": 617,
      "Factor": 0.98,
      "Frequency": 49,
      "Voltage": 231,
      "Current": 14.747
    }

From my point of view a much better way to run that really excellent device! 

Robot mops for large rooms, gyms or similar (3)

After testing several robot mops (posting 1) iRobots Roomba did the job (posting 2).

A Roomba Max 705 is running in our gym and after the first weeks here some findings (if you want to run such a robot mop in a large hall/gym/etc.

By the way cleaning a space with >200m² is no problem:

And access routes with >30m to the room, where the robot should clean work as well:

But to get there, the following things have to be considered:

• If your gym has floor-to-ceiling mirrors: You have to cover the mirrors during mapping phase. Otherwise Roomba calculates the room larger than it is and if another room is behind the mirror, it will create doors/openings which are not there...
• Gym walls are typically uniform - and with an empty gym the robot has not landmarks to navigate. So you have to put some stickers on the wall. (Consider the robot is far away from the edges and sees with the lidar only the wall and the camera can not recognize anymore, that is moving forward... the robot can not distinguish if it is slippery or stuck or still moving).
• If you want to mop your gym at night: the stickers should reflect light - in darkness Roomba switches on its LED, so reflectors will guide the robot
  

The video shows that problem quite well - a smartphone camera is may be better than the camera of the Roomba and you can imagine that the robot is really a little bit lost. But if you move down to the level of the robot, the light of the LED is reflected for the smartphone camera as well, and the the landmarks are clearly visible.

By the way: after you created the landmarks you have to run the mapping again, so these landmarks are stored in the map (i created them after the first mapping and it helped but Roomba did not find its way everytime. After mapping the gym again it is now running without any failure.) 

 

 

Robot mops for large rooms, gyms or similar (2)

 After testing these robot mops

• Dreame X40
• Roborock S8 MaxV Ultra
• Eufy S1 Pro

with very bad results for large rooms, gyms or similar (read this article) i tested a small product from roomba:

• iRobot Roomba 205 

and that robot did really a good job:

and it was able to really clean the room even if all walls are more than 6m away:

 

That is really amazing! From my point of view that could be due to

• iRobot is using LIDAR sensors which can work in ranges with more than 6m
• iRobot has better developers, which can deal with the fact: "robot does not detect anyhing" and it just moves on...

For our gym we will now purchase the Roomba Max 705 because vacuuming is not so important - we need mopping :) 

Small Solar Plant with Growatt Nexa 2000: Monitoring...

After my first steps with Growatt Nexa 2000 now the challenge is to integrate this device in my monitoring at home. If you are interested: This is the link to my setup and monitoring via Zigbee or getting data from my FritzBox. 

To get the status of the device there are the following options:

• Mobile app
  Just install the "Shine phone" app and create an account there. With that app you can configure really everything and the data provided there is nicely processed.
• Web frontend
  Via https://openapi.growatt.com/index it is possible to access all the data provided by Growatt:
  
  
  

With these dashboard you have to export the data manually.

But there is a nice software provided here : https://github.com/mtrossbach/noah-mqtt

This does not only work with NOAH - it is although working with NEXA, because it fetches the data from the web APIs from Growatt.

My approach:

• Download the compiled binary for arm64 
  https://github.com/mtrossbach/noah-mqtt/releases
• And run it like provided here: 
  https://github.com/mtrossbach/noah-mqtt?tab=readme-ov-file#option-2-downloading-and-running-a-prebuilt-binary
  (change the variables for username/password!)
• Start the binary noah-mqtt 
  the data is then written into MQTT
• Configure telegraf
  so that the data from MQTT is written into your influxdb

And after that i was able to build my own dashboard in grafana again. With the advantage, that i have hourly graphs as well because the noah-mqtt is sampling every 30s.