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SWAP THE MANUFACTURER'S WIFI DONGLE FOR AN ESP8266 AND THE APPLIANCE RUNS ON YOUR NETWORK

Swap the dehumidifier's cloud Wi-Fi dongle for an ESP8266 and it speaks MQTT on your own network instead — no account, no vendor cloud.

by Hypfer

FULL CAD BOM FIRMWARE DOCS

HomeAutomation

Built withESP8266

difficulty
●●○○○
time
an evening
license
Apache-2.0
repo
repo STABLE (NO CHANGES SINCE 2024)190 stars

WHAT YOU’LL NEED

1
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COMPAREE VERDICT

This is what the open-source smart home was supposed to be: you unplug the dehumidifier, pull the manufacturer's Wi-Fi dongle from its USB port, plug in an ESP-01 adapter you flashed with the project's firmware, and the appliance afterwards speaks MQTT on your own network and shows up in Home Assistant through autodiscovery. No account, no servers that might shut down, no route through someone else's cloud. The adapter is built from off-the-shelf parts — an ESP-01, a level-shifter adapter board and a USB-A-to-terminal plug — and the README shows a photo of the finished one. The companion humidifier project works differently: it reflashes the Xiaomi Mi Smart Antibacterial Humidifier's own Wi-Fi module, which needs a USB-UART adapter and some soldering. The tested list for the dehumidifier project covers the Midea MAD22S1WWT, Comfee MDDF-16DEN7-WF and MDDF-20DEN7-WF, Inventor Eva II PRO and EVA ION PRO 20L, and Midea Cube 20/35/50; the author expects it to work with all Wi-Fi-enabled Midea-made dehumidifiers. If your model is supported, this is a clean evening's work and the payoff is permanent local control.

GOOD TO KNOW

  • —Both repositories include firmware, a parts list and MQTT topics, and Home Assistant picks the devices up via MQTT autodiscovery; the dehumidifier README also shows a photo of the finished adapter.
  • —The dehumidifier project lists five tested Midea, Comfee and Inventor models plus the Midea Cube in three capacities; the humidifier project covers one Xiaomi model.
  • —No PCB — the adapter is an ESP-01 module on an off-the-shelf level-shifter board, connected to the unit's USB-A dongle port through a USB-A-to-terminal adapter.
  • —Both projects are Apache-2.0, allowing commercial use.
  • —The dehumidifier README includes an explicit safety warning for R290 propane units—the refrigeration circuit must never be opened.
  • —No video walkthrough is linked; the README text and its photos of the finished adapter are the documentation.

Parts to buy

5 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • ESP8266 ESP-01 moduleFind
  • ESP-01 serial adapter board with 3.3V-to-5V level shiftersFind
  • USB A to terminal plug adapterFind
  • Dupont cablesFind
  • USB-to-ESP-01 programmer for flashingFind

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Can I build this?

Printnothing required
BuyESP8266 ESP-01 module, ESP-01 serial adapter board with 3.3V-to-5V level shifters, USB A to terminal plug adapter, Dupont cables, and a USB-to-ESP-01 programmer for flashing
ToolsUSB-to-ESP-01 programmer for flashing, screwdriver to open the appliance housing
Skillsbasic soldering, comfortable flashing firmware to an ESP8266, ability to follow a pinout diagram—no prior MQTT or Home Assistant experience required but helpful
Timean evening: an hour to flash and wire, another to configure Home Assistant if new to it
Cost$ — a handful of cheap off-the-shelf parts: ESP-01, adapter board, USB-A terminal plug and Dupont cables.
SafetyMains appliance—unplug before opening. The swap only touches the low-voltage control header. R290 propane units: the sealed refrigeration circuit must never be opened or drilled (leak around ignition sources is a fire and explosion risk); this project does not touch it.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

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Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Check the README's compatibility list — if your model is not on it, you are testing it yourself (Only the listed models are tested; the author expects any Wi-Fi-enabled Midea-made dehumidifier to work, but anything unlisted is at your own risk.)
  2. 2.Flash the firmware to an ESP8266 board using the flashing guide (Build and flash with the Arduino IDE after adding ESP8266 board support and the four libraries the README lists.)
  3. 3.Assemble the adapter: ESP-01 on the level-shifter board, wired to the USB-A terminal plug with Dupont cables, matching the photo in the README (The guide assumes the USB-A dongle port; some units use a JST-HX connector instead, and the Comfee MDDF-20DEN7 has no USB port at all. Compare your parts with the finished-adapter photo in the README.)
  4. 4.Unplug the appliance, remove the manufacturer's wifi module, plug in the ESP8266(The ESP adapter goes into the USB-A port where the Wi-Fi dongle sat. Some units use R290 (propane) refrigerant — be extra careful not to damage anything while disassembling.)
  5. 5.Connect the adapter to your Wi-Fi and MQTT broker via its setup access point; Home Assistant then discovers it automatically (Home Assistant finds the dehumidifier automatically via MQTT autodiscovery — no YAML needed.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Buying an untested Midea or Comfee model and assuming it will behave exactly like the tested ones — the author expects all Wi-Fi-enabled Midea-made units to work, but only the listed ones are confirmed.
  • Skipping the compatibility check and discovering after opening the appliance that it has no USB-A dongle port — some units use a JST-HX connector, and the Comfee MDDF-20DEN7 has no USB port at all.
  • Confusing the dehumidifier and humidifier projects—they are separate repositories with different firmware and different supported models.
  • Attempting to use this on a non-wifi appliance or one with a different control module (some Midea units use a completely different system).
  • Opening an R290 propane unit without reading the safety warning—the refrigeration circuit must never be drilled or opened, though this project does not touch it.
  • Assuming MQTT will work without configuration—you need a working MQTT broker on your network first, and the ESP needs the broker IP and credentials.

Will this work on my Midea dehumidifier?

The tested list is: Midea MAD22S1WWT, Comfee MDDF-16DEN7-WF and MDDF-20DEN7-WF, Inventor Eva II PRO WI-FI, Inventor EVA ION PRO WiFi 20L, and Midea Cube 20/35/50. The author expects it to work with all Wi-Fi-enabled Midea-made dehumidifiers, but untested models are at your own risk.

Do I need to run Home Assistant?

No — the appliance speaks MQTT after the swap, so any MQTT-capable system will work. Home Assistant picks it up automatically via autodiscovery, and the README shows the JSON commands for everything else.

Can I still use the appliance's physical buttons?

Yes—the ESP replaces only the wifi module, the rest of the control board is untouched.

What is the R290 propane warning about?

Some supported units, such as the Comfee MDDF-20DEN7-WF, use R290 — propane — as refrigerant. The README warns to be extra careful when disassembling, because a leak can cause a fire or explosion. The project itself only swaps the Wi-Fi dongle in its USB port; unplug the appliance before you open it.

Is there a PCB to order?

No — you buy an ESP-01 module, an ESP-01 adapter board with 3.3 V-to-5 V level shifters and a USB-A-to-terminal adapter, and plug it into the port where the original Wi-Fi dongle sat. The README shows a photo of the finished adapter to compare against.

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Discussion1

FROM THE COMPAREE TEAM

The README lists eight tested dehumidifiers from Midea, Comfee and Inventor, including the Midea Cube in three sizes, and the author expects any Wi-Fi-enabled Midea-made unit to work. If you have one, what pushed you to swap the cloud dongle rather than just leaving the Wi-Fi off?

CompareeTEAM2mo agoedited

Practical notes from our verification: both repositories are by Hypfer, the author of Valetudo, and both use the Apache-2.0 licence, which allows commercial use; neither has seen code changes since 2024 for the dehumidifier and 2021 for the humidifier, so treat them as finished rather than actively developed. The dehumidifier adapter needs no PCB and no soldering in the unit: an ESP-01 module sits on a 3.3V-to-5V level-shifter adapter board and plugs into the unit's USB-A Wi-Fi dongle port through a USB-A-to-terminal adapter and Dupont cables, and you flash it from the Arduino IDE. Home Assistant picks it up through MQTT autodiscovery. The README warns that some supported units use R290, which is propane, so take extra care not to damage anything when you open one up. The humidifier project is different: it replaces the firmware on the device's own ESP8285 Wi-Fi module and does need temporary soldered wires for flashing. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Hypfer

Hypfer is the developer behind Valetudo, the open-source project that removes the cloud from robot vacuums and gives them local MQTT control. These dehumidifier and humidifier projects apply the same approach to a different category of appliance — either replacing the manufacturer's Wi-Fi dongle with an ESP8266 adapter or reflashing the existing Wi-Fi module, so the device speaks to your own network instead of the company's servers.

GitHub

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