DIY WiFi Switch: A Complete Guide From Schematic to Setup

Controlling lighting via a smartphone or voice assistant is no longer a fantasy - all you need to do is assemble WiFi switch Do it yourself. Such a project will cost 2-3 times less than ready-made solutions from Xiaomi or Sonoff, and the functionality can be adapted to your needs: from simply turning on a lamp to integration with Home Assistant or Google Home.

In this article you will find Current connection diagrams for 2026, taking into account the new ESP32-C6 and ESP8266-S3 modules, step-by-step instructions for flashing (including alternatives Tasmota And ESPHome), as well as solutions to common problems—from connection drops to router conflicts. We'll cover options for both experienced radio enthusiasts (soldering and MQTT setup) and beginners (ready-made boards from AliExpress).

1. Choosing Components: What to Buy for a WiFi Switch

The basis of the homemade switch is WiFi module And relayTheir choice determines operational stability, energy consumption, and compatibility with smart home systems. The following options are relevant in 2026:

• 📶 ESP8266 (NodeMCU, Wemos D1 Mini) — a budget option for simple tasks. It supports 2.4 GHz, but can be slow when there are many devices on the network.
• 🚀 ESP32 (ESP32-C3, ESP32-S3) — optimal for complex scenarios (for example, with motion sensors). Operates on 2.4 GHz and 5 GHz (in newer versions) and has more memory for firmware.
• ⚡ Ready-made Sonoff Basic or Shelly 1 boards — if you don't want to solder. They already contain relays and connectors, but require reflashing for full control.

For relays, select modules with opto-isolator (For example, Songle SRD-05VDC-SL-C) — they protect the microcontroller from power surges in the 220V network. The relay's power must exceed the lamp/device load by at least 30%. For example, a 10A relay is sufficient for a 100W LED strip, while a 2kW heater requires a 16A module.

⚠️ Attention: If you choose ready-made devices (Sonoff, Shelly), check their compatibility with your router. Some models conflict with networks where 802.11r (Fast Roaming) or WPA3-Enterprise.

2. Connection diagrams: from simple to complex

The scheme depends on whether you will be driving one lamp or several channels (for example, a chandelier with separate groups of lamps). Below are three proven circuits with pin assignments for ESP8266 And ESP32.

Scheme 1. Single-channel switch (ESP8266 + relay)

220V → Relay (NO) → Lamp → 220V (N)
ESP8266:
- GPIO5 → IN (relay)
- VIN → 5V (power supply)
- GND → GND

Scheme 2. Two-channel switch (ESP32 + 2 relays)

ESP32:
- GPIO18 → Relay 1 (IN)
- GPIO19 → Relay 2 (IN)
- 5V → VCC (relay and ESP)
- GND → GND

Scheme 3. Switch with button (for manual control)

ESP8266:
- GPIO4 → Button (with pull-up to 3.3V)
- GPIO5 → Relay (IN)
- When the button is pressed, the ESP sends a command to switch the relay

3. Firmware: Tasmota vs. ESPHome vs. Custom Logic

The firmware determines how you will control the switch: through MQTT, the manufacturer's cloud, or a local network. Let's consider three popular options:

• 🔧 Tasmota — universal firmware with a web interface. Supports Home Assistant, Google Home, AlexaDisadvantage: Requires manual configuration.
• 🏠 ESPHome - ideal for integration with Home AssistantAllows you to write configs in YAML, but is more difficult to set up for beginners.
• ☁️ Proprietary software (For Sonoff/Shelly) - simplicity, but dependence on the cloud and limited functionality.

To flash you will need:

1. Download Tasmota or ESPHome from the official website.
2. Connect ESP to computer via USB.
3. IN Arduino IDE or PlatformIO select board (ESP8266 NodeMCU or ESP32 Dev Module).
4. Download firmware via Tools → Burn Bootloader (if necessary) and Sketch → Upload.

Download Arduino IDE or PlatformIO|

Install drivers for ESP|

Select the correct board in the settings|

Disable antivirus (may block download)|

Connect the ESP to USB 2.0 (USB 3.0 may cause errors)

-->

After flashing:

1. Connect to an access point tasmota-xxxx or esphome-web.
2. Enter your WiFi network details.
3. Set up MQTT (if you use Home Assistant) or cloud service.

⚠️ Attention: When flashing Sonoff Basic through TX/RX the pins need to be shorted GPIO0 on GND before applying power, otherwise the bootloader will not activate.

4. Smartphone setup: apps and integrations

After assembly and firmware installation, the switch needs to be connected to the control system. Let's consider three methods:

• 📱 eWeLink application (For Sonoff) is simple, but requires registration and works through the cloud. Supports voice commands for Alice's And Google Assistant.
• 🏡 Home Assistant — local management without the cloud. You need to add the device through Integration → MQTT or ESPHome.
• 🗣️ Voice assistants - for this in the settings Tasmota turn on Enable Alexa or Enable Google Home.

Example of setting in Home Assistant (For ESPHome):

Configuration fragment configuration.yaml
switch:
- platform: mqtt
Name: "Light in the Hallway"
command_topic: "cmnd/sonoff_power1/Power"
state_topic: "stat/sonoff_power1/POWER"
payload_on: "ON"
payload_off: "OFF"

For Tasmota use standard MQTT commands:

• cmnd/<device>/Power ON - turn on;
• cmnd/<device>/Power OFF — turn off;
• cmnd/<device>/Status 10 — status request (every 10 seconds).

5. Installation and assembly: safety rules

Before installing the switch in the electrical network Necessarily Disconnect the power at the panel and check for voltage with a voltage indicator. Even the low-voltage part (ESP and relay) must be isolated from 220V!

Step-by-step installation:

1. Secure the board to the enclosure (socket box or junction box).
2. Connect phase (L) to one relay contact, and zero (N) - directly to the lamp.
3. Withdraw relay output (NO) to the lamp.
4. Connect the 5V power supply to the ESP and the relay (if active).

Accommodation options:

• 🔌 Instead of a regular switch — If you're using the housing from an old switch, you'll need to run a 5V power cable inside the wall.
• 📦 In the junction box — if you don't want to damage your walls. Cons: you'll only have to control it from your smartphone.
• 🖥️ In a separate housing next to the lamp — for table lamps or garlands.

⚠️ Attention: If you are installing the switch in a bathroom or outdoors, use an enclosure with a protection class IP65 and sealed terminal blocks. ESP and relays are sensitive to moisture!

6. Troubleshooting: Why the WiFi Switch Doesn't Work

Typical malfunctions and how to fix them:

If the switch operates erratically (for example, it switches off after 10 minutes), the cause may be:

• 🔋 Router energy saving mode — turn it off WiFi Power Save in the settings;
• 📶 Weak WiFi signal - install a repeater or use ESP with an external antenna;
• ⚡ Interference from other devices — change the WiFi channel to 1, 6 or 11 (manually).

7. Advanced features: timers, sensors, voice control

The basic WiFi switch can be expanded with additional features:

• ⏰ Timers and schedules - V Tasmota configure via Configuration → Timers. Example: 0 8 1-5 ON (turn on at 8:00 on weekdays).
• 👁️ Motion sensor — connect HC-SR501 to GPIO. B ESPHome add:

  binary_sensor:
  - platform: gpio
  pin: GPIO14
  Name: "Movement in the Hallway"

• 🌡️ Temperature control - use the sensor DHT22 and the rule is in Home Assistant:

  automation:
  trigger:
  platform: numeric_state
  entity_id: sensor.temperature
  above: 25
  action:
  service: switch.turn_on
  entity_id: switch.ventilation

For voice control via Alice (Yandex) or Google Assistant:

1. IN Tasmota turn on Enable Alexa in the settings.
2. In the assistant app, add the device via Smart Home → Add Device.
3. Say: "Alice, turn on the light in the hallway" (the name must match Friendly Name V Tasmota).

FAQ: Answers to frequently asked questions

binary_sensor:
- platform: gpio
pin:
number: GPIO0
mode: INPUT_PULLUP
inverted: true
name: "Mechanical button"
on_press:
then:
- switch.toggle: relay_1