QOB-WFD4103 WiFi Switch power voltage current monitoring support

User question

Did any one successfully enable power/voltage/current monitoring on this device?
WiFi Switch QOB-WFD4103 (WFD4103)

Artificial Intelligence Response

Direct answer to the question

No — I am not aware of anyone successfully enabling power, voltage, or current monitoring on the WiFi Switch QOB-WFD4103 / WFD4103, and based on the known teardown information, it is not practically enableable in firmware.

The WFD4103 appears to be a basic on/off smart switch, not an energy-monitoring smart plug. The known hardware configuration exposes only:

Pin	Function
P7	Status LED, active-low
P24	Relay
P26	Button

The published teardown identifies the device as using a Tuya WB2S module based on the Beken BK7231T, with configuration for LED, relay, and button only. No metering IC or metering GPIO assignments are shown. (elektroda.com)

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Detailed problem analysis

Power/voltage/current monitoring is not just a software feature. A smart plug or switch needs dedicated measurement hardware, typically including:

• A current-sense shunt resistor or current transformer.
• A voltage divider network connected to the AC line.
• An energy-metering IC, for example:
  • BL0937
  • BL0942
  • HLW8012
  • CSE7766 / CSE7777
• GPIO or UART connections between that metering IC and the Wi-Fi MCU.

On devices that support energy monitoring, firmware such as OpenBeken, Tasmota, or ESPHome reads pulses, serial data, or ADC-derived measurements from that metering circuit. Without the analog front-end and metering IC, the MCU has no safe or meaningful way to know load current, line voltage, watts, or kWh.

For the WFD4103, the documented OpenBeken-style setup is only:

P7 = LED_n
P24 = Relay
P26 = Button

That is the profile of a simple relay switch. There are no extra pins assigned to BL0937CF, BL0937CF1, HLW8012, CSE7766, BL0942, voltage, current, or power measurement functions. The teardown also describes the device as having one button, LED, relay control, and a WB2S/BK7231T module, with flashing via UART. (elektroda.com)

So the limitation is hardware, not firmware.

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Why firmware cannot add this feature

A common misunderstanding is that because some Tuya, Enbrighten, Sonoff, or generic smart plugs support power monitoring, a visually similar plug might be unlockable by changing the firmware. That is only true if the metering hardware is already installed on the PCB.

In the WFD4103 case:

• The MCU can switch the relay.
• The MCU can read the button.
• The MCU can drive the LED.
• But it has no documented connection to an energy-measurement IC.
• There is no known current-sense path exposed to firmware.
• There is no known calibrated voltage-sense path.

Therefore, OpenBeken, ESPHome, LibreTiny, or Tasmota-like firmware can give you local control, MQTT, HTTP commands, and Home Assistant integration, but not real voltage/current/power telemetry unless the PCB actually contains measurement circuitry.

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Practical guidelines

If you want to verify your specific unit, inspect the PCB for the following:

Signs that power monitoring exists

Look for:

• A large low-value shunt resistor, often marked something like:
  • R001
  • R002
  • 1mΩ
  • 2mΩ
  • 5mΩ
• A metering IC near the mains path, commonly marked:
  • BL0937
  • BL0942
  • HLW8012
  • CSE7766
  • CSE7759
• Thin sense traces from line/neutral to a small IC.
• Three typical metering GPIO connections: CF, CF1, and SEL, or a UART pair for chips such as BL0942/CSE7766.

Signs that it does not exist

The WFD4103 known layout appears to match this case:

• Relay only.
• Small isolated or capacitive power supply.
• Wi-Fi module.
• Button and LED.
• No shunt resistor.
• No metering IC.
• No metering GPIOs in the firmware template.

If your PCB matches the published WFD4103 teardown, then voltage/current/power monitoring cannot be enabled.

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Possible alternatives

If you need energy monitoring, use a device sold explicitly with that feature. Suitable categories include:

• Smart plugs with built-in power monitoring

  • Sonoff S31
  • Shelly Plug US
  • TP-Link/Kasa energy-monitoring models
  • Athom or Kauf plugs pre-flashed with Tasmota/ESPHome

• Zigbee smart plugs with energy monitoring

  • Often more stable for Home Assistant installations because they avoid adding more Wi-Fi clients.

• External metering

  • Clamp CT sensor around the circuit.
  • DIN-rail energy meter.
  • Shelly EM / Shelly Pro EM.
  • Emporia Vue or similar panel-level monitor.

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Safety note

Do not attempt to add current or voltage monitoring directly inside the WFD4103 unless you are experienced with mains-rated PCB design. Adding a shunt, voltage divider, or metering IC inside a UL/FCC-listed mains device can compromise:

• Creepage and clearance.
• Thermal performance.
• Fire safety.
• Isolation.
• Regulatory compliance.

For practical use, replacing the switch with a proper metering model is much safer than modifying the WFD4103.

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Brief summary

The QOB-WFD4103 / WFD4103 can be flashed and used for local relay control, but there is no known successful method to enable power, voltage, or current monitoring because the required metering hardware is not present in the known design. It should be treated as an on/off-only Wi-Fi switch.

Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.